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OLD_S294: Postharvest Quality and Safety in Fresh-cut Vegetables and Fruits

Annual/Termination Reports (SAES-422): [06/28/2006] [04/29/2007] [05/04/2008] [04/21/2009] [03/01/2011] [07/13/2011]

Date of Annual Report: 06/28/2006

Report Information:
  • Annual Meeting Dates: 04/26/06 to 04/30/06
  • Period the Report Covers: 06/2005 to 06/2006

    • Participants:
    Brief Summary of Minutes of Annual Meeting:

    URL: Copy of minutes
    Accomplishments:

    Impact Statements:
    Last Modified: unknown

    Date of Annual Report: 04/29/2007

    Report Information:
  • Annual Meeting Dates: 04/27/07 to 04/29/07
  • Period the Report Covers: 10/2006 to 09/2007

    • Participants:
    Brief Summary of Minutes of Annual Meeting:
    Minutes of S-294 Business Meeting Pueblo A/B Rooms, Wyndham Hotel Palm Springs, CA Saturday, April 28, 2007

    Project: S-294 Postharvest Quality and Safety in Fresh-cut Vegetables and Fruits

    Offices (2006-2007)

    Chair: Peter Toivonen Vice-chair: Aubrey Mendonca Secretary: Xuetong Fan

    Peter Toivonen called the meeting to order at 12:40 pm, and asked attendees for a brief introduction. All attendees introduced him/herself.

    Peter asked for approval of the 2007 meeting agenda. The agenda was unanimously approved.

    Peter asked for suggestions of date for next years S-294 meeting. Because the schedule for the FreshTech meeting has not been finalized yet, S-294 meeting time can not be decided. Peter said the next S-294 leadership will decide the time and duration (half or whole day) for next year S-294 meeting.

    Peter asked for comments on the minutes of April 2006 meeting in Baltimore, MD. Aubrey Mendonca said the minutes were posted on the S-294 UC Davis website. Peter requested an approval of the minutes. John Beaulieu was the first to call the motion and Bill Hurst was second. The minutes were unanimously accepted. Report of administrative adviser, Reuben Moore Reuben praised S-294 group for the productivity. He said S-294 is the most productive among all groups in the Southern Association of Agricultural Experiment Station Directors projects. He welcomed industry representatives attending the meeting and was happy to see several people from the produce industry in the room. He said there are 76 members for the S-294 project, one of the largest ones. He raised concerns about the uncertainty of Hatch fund and budget for agricultural research. He anticipated an increase in the number of regional projects involving multiple institutions. He visited Dr. Gail Buchanan, Undersecretary of USDA, a few weeks ago. There are many uncertainties about 07 budget. The elimination of earmarked funds is a concern. Budget cut affects Universities and USDA. There is uncertainty about 08 budget. USDA has proposed to consolidate ARS and CSREES into a single agency, named Research, Education and Extension Service (REES). A Chief Scientist would be in charge of the REES. REE would become office of Science. The USDA also proposed in the Farm Bill a $50 million for bio-energy research Initiative, $100 million Specialty Crop research Initiative and $10 million for organic research. Reuben suggested that S-294 scientists may apply for the Specialty Crop research fund when available.

    Reuben wanted to make sure that we are working on each objective of the project and asked whether we need to make any change on the objectives. He would like to be notified about significant impacts. Documenting impact is important, and should appear on the annual report.

    Remarks from David Gombas, Vice President of UFPA David asked for thoughts and opinions about the meeting. There are 1200 members after IFPA combined with United Fresh Fruits and Vegetables Association. David reminded attendees that scientists should continue to work in the area of produce quality, even though produce safety is important. David said he is happy with the quality of the science symposium and food irradiation symposium. He would like to see more people attend the two symposiums. About 1500 people are at the meeting, but only about 300 people attended the 4 technical sessions held simultaneously. There are lots of people in the food safety summit session.

    Bill Hurst asked the reason for running so many sessions simultaneously. Diane Barrett wanted to know the number of technical people attending the meeting. David said he did not know but the FreshTech meeting was primarily for technical people. John said that the topics in the food safety summit research insight forum were too diluted, needed more focus. David asked about opinions about the poster section and research pavilion. Alan Lefcourt proposed to change the location and orientation of posters to attract more people. Mikal Saltveit suggested setting up the posters in the lunch area. John believed that having the ARS booth was a big success, giving industry people a place to go for information, so that we did not have to look for people. Jeff said he spent the whole time manning the booth, no time to participate in other sessions. There is a challenge to find enough people to man the booth.

    Yaguang Luo suggested an S-294 booth for next years FreshTech meeting. Diane agreed. Alan suggested that a message board (or similar mechanisms) should be established so that those with specific requirements about technical problems can meet with scientists with expertise and solutions. The posters are too close to each other, need more room between the posters for people to see the posters.

    David said we had 19 posters presented this year. The quality of posters is very good. The judges had a difficult from making the decision on the best poster. This years winner of best poster goes to Yaguang. David reflected a comment from one judge saying that one of the posters was not well prepared. He reminded scientists to spend time and effort in preparing the poster, and not just to get the free access pass to the meeting. Jeff and Xuetong asked about availability of presentations and poster abstracts on website. David said the presentation should be on the website (either on FreshTech or United Fresh) within a month or so. David said next years FreshTech meeting will be in Las Vegas, May 5-7 (Mon-Wed), which will be run concurrently with the Marketplace meeting. John was concerned with the visibility of S-294 at the Las Vegas meeting when the two meetings are combined. David said there would be two separate shows at the same time, should not affect the visibility of S-294. John suggested the Food Safety and Technology Council meeting not be held on Sunday.

    Peter asked for nominations of new secretary. John nominated Ann Plotto to be next secretary. Peter asked for more nominations. There was no more nomination. Mikal motioned to approve Anne as the new secretary. Anne was unanimously confirmed as new S-294 secretary.

    Peter reminded people to send their Station reports to him so that he can compile S-294 annual report. Also, he reminded everyone to update his or her profile on the UC Davis websites.

    Jeff said that Randy, Jeff and Liz submitted a NRI proposal on enzyme and volatile of melons.

    Oral Reports from S-294 Participants The following participants presented reports on research at their reprehensive institutions for the 2006-2007 reporting period.

    Anne Plotto reported on quality and flavor research at USDA, ARS Citrus & Subtropical Products Lab. John Beaulieu reported on antimicrobial activities of CPC and ASC on cantaloupes at USDA, ARS, SRRC. Diane Barrett reported her work on analysis of texture and measurement of tissue integrity at UC Davis. Jeff Brecht reported on quality and postharvest physiology research at Univ. Florida. Xuetong Fan reported work on quality and microbiology work at USDA, ARS, ERRC. Randy Beaudry reported work on 1-MCP absorption and gas permeability model at Michigan State Univ. Aubrey Mendonca reported work on microbial detection and combination of irradiation and sanitizers at Iowa State Univ. Jinhe Bai reported work on package and ethanol vapor at Oregon State Univ. Peter Toivenen reported work on 1-MCP releasing, and ATP at Agric. Agric.-Food Canada. Mikal Saltveit reported work on reduction of lettuce browning at UC Davis. Marita Cantwell reported work on vitamin C and reduction of sunchoke browning at UC Davis. Bill Hurst reported work on pathogen ecology and reduction at Univ. Georgia. Jorge Fonseca reported work on pre-harvest factors and quality at Univ. Arizona. Roberto Avena-Bustillos reported work on antibrowning coating at USDA, ARS, WRRC. Moon Kim reported work on imaging technology at USDA, ARS, BARC Yaguang Luo reported worked on sanitizers and hot water at USDA, ARS, BARC.

    Following Davids suggestion, Peter asked the remaining industry representatives to make brief remarks. Art Davis of Green Giant Fresh said he used to work with Bacon industry, and there were much more collaborations between industry and academics. Industry provided research funds. He thought that fresh produce industry was more loosely constructed. He encouraged scientist to meet with people and listen to the needs of industry people, and find a person who needs solutions. Produce industry was more diversified, but produce industry can learn from meat industry. Jeff suggested that United Fresh establishes an advisory committee for the S-294 group so that the need of industry could be heard by S-294 scientists. David said there were 4-5 S-294 members on the Technology Council who should report back to S-294 scientists. Peter said the apple research group meeting held for last 3-4 years provided a platform to get research priorities on apples.

    Barry Eisenberg, co-chair of the UFPA Technology Council said the industry had written research proprieties. One of the areas is food safety. There are regional process facilities throughout the country. He said that Western Grower maintains a list of experts. He also said many practices in the industry have no scientific justification. Many need back-up from scientific data. He said a large number (~70) of people on the Technology Council can not achieve anything. A smaller work group consisting of 3-5 people is desired. The industry as a whole should figure out how to raise funds for research. He said that individual companies have funded research. For example, Fresh Express established a $2.5 millions research fund. If the industry works together, much more funding will be raised for research. Research should focus on technologies that can be commercially applied. The industry needs to establish a mechanism to raise money and ask other members to support. Each research institution has own expertise. We can learn from the alliance between McDonald and Disney which benefits each party.

    John asked David about the Research Center established at UC Davis using the funds from Industry and PMA. David had no comment.

    Reuben thanked the presence of Industry representatives, and encouraged them to join the meeting next year. He also asked industry to support research.

    Bill said that National Cattlemans Beef Association has a mechanism to raise money by taking $1/ cattle for research. Xuetong said that the Washington State Apple Commission also raises research money ($0.25 per box of apples). Art Davis said Dole is tacking on food safety surcharges, charging $0.20 more each carton beginning April 29, 2007. However, for UFPA, it is hard to collect even 2 cents. California Department of Agriculture charged $0.02 /carton for inspection. He reminded the consequence of spinach outbreaks: 25% of loss in spinach consumption. UFPA needs a change so that research funds can be raised. Anne asked about the difference between PMA and UFPA. David said that PMA is for marketing/retailers while UFPS is for processors. David said the industry is very surprised by the overhead charged by University. There are also many activities scheduled to lobby congress to support produce industry. John suggested that S-294 scientists wear a uniform or hat to identity themselves.

    At 4:30: Aubrey took over from Peter (who needs to catch a plane) to chair the session.

    Ozgur Koc of Earthbound Farms said he has been working with Earthbound for 7 months. Before that, he worked with Crunch Pak. Crunch Pak funded a research project to Gerald Sapers about de-contamination of antibrowning solutions. Jeff said someone needs to take a lead to put ideas together to apply for funds.

    Yaguang said the idea of raising money for research has come out before and has support form Jim and David, but never went through. Barry said we should know whether there are research funds available very soon.

    There is not enough time to discuss activities and plans coordination efforts, grand proposals.

    Aubrey adjourned the meeting at 5pm.

    Accomplishments:
    Accomplishments:

    Objective 1. Develop, evaluate, and standardize subjective and objective quality evaluation methods in intact and fresh-cut fruits and vegetables.

    " The catechol and nitroso visual assays of Kader and Chordas (1984) were adapted using fresh-cut mango slices to visualize the distribution of PPO and phenolics, respectively, within the mesocarp. (Brecht)

    " Digital images of several fresh-cut products were associated with previously developed rating systems for inclusion in the database developed by project participants at UC Davis. (Brecht)

    " A rapid method for extraction and determination of lycopene content has been developed and verified. (Barrett)

    " A book chapter for the Ingersoll Rand Encyclopedia on methods of measuring fruit and vegetable quality has been written and should be published in 2007. (Barrett)

    " Methods for comparing analytical and sensory methods of analysis of tomatoes and oranges has been initiated. (Baldwin and Plotto)

    " A comparative study for antioxidant contents and flavors in tropical fruits was completed. (Baldwin and Plotto)

    " A trained panel developed and implemented for study of flavor and aroma profiling of 1-MCP treated versus non-treated tomatoes. (Baldwin and Plotto)

    " Rank testing (an approach not requiring a trained panel) was utilized to compare mangoes, oranges and tangerines with different coatings and effects of enzyme peel pre-cut treatments of oranges.(Baldwin and Plotto)

    " Off-the-shelf ATP swab kits are being evaluated for their utility in rapid assessment of maturity in apples. Initial results indicate a dramatic drop in measured ATP levels at the time of induction of ethylene climacteric in Granny Smith apples (Toivonen).

    Objective 2. Develop new strategies to maintain fresh-cut product quality

    " The influence of the ethylene action inhibitor, 1-methylcyclopropene (1-MCP), on shelf life and deterioration of fresh-cut cantaloupe during storage was determined. Intact 3/4 to full-slip cantaloupes were treated with 1-MCP, then fresh-cut cubes and intact fruit were stored for 12 d at 5C. The more physiologically advanced distal tissue developed significantly more watersoaking than the less advanced portions. Firmness retention was better in 1-MCP treated intact fruit, but the effect of 1-MCP on firmness retention and watersoaking of fresh-cut cubes was variable. 1-MCP did not significantly influence flesh color or soluble solid contents of either intact cantaloupe fruit or fresh-cut cubes. (Brecht & Huber)

    " The effectiveness of 1-MCP applied continuously to fresh-cut tomato slices during storage for 10 d at 5C in a modified atmosphere package (MAP) was no better compared to slices from whole fruit treated with 1-MCP prior to slicing and storage, however, all 1-MCP treatments reduced gel loss and juice leakage compared to controls not stored in MAP. (Brecht & Huber)

    " Ripe papaya fruit were treated with 1-MCP, immediately processed into fresh-cut slices or left intact, and stored for 10 d at 5C. Ethylene production by mesocarp tissue was not significantly affected. Firmness of slices and intact fruit mesocarp was significantly better retained by 1-MCP. Electrolyte leakage remained low and changed little in intact fruit while increasing in slices after 4 d; after 6 d control slices were higher than slices from 1-MCP-treated fruit. Microbial counts in stored slices were generally unaffected by 1-MCP. Informal sensory analysis indicated that the edible shelf life was 6 d in slices from 1-MCP-treated fruit compared with 2 to 3 d for slices from control fruit. (Huber)

    " Low temperature blanching was found to inactivate pectin methyl esterase and thus firm tissues of 10 different vegetables. (Barrett)

    " Heating the cut ends of leaves in cored iceberg lettuce reduces subsequent phenolic accumulation and tissue browning. (Saltveit)

    " Development of a decision-support tool for MA packaging (Beaudry). MS-Excel program which allows user to select an appropriate MA-film for a particular fruit or vegetable product.

    " Evaluated 1-MCP sorption by target plant materials and found that those containing cellulose absorbed significant quantities of 1-MCP, which might compromise efficacy (Beaudry).

    " Antimicrobial phytochemicals with distinctive flavors can be incorporated in compatible fresh-cut fruits and vegetables achieving similar flavors as already accepted by consumers in salad dressings and fruit-based desserts (Avena-Bustillos).

    " Hot water treatment of whole cantaloupe on reduction of microbial populations and quality of subsequent fresh-cut cubes was evaluated. (Beaulieu and ERRC).

    " Risk of furan formation in fresh cut produce in response to irradiation treatment was evaluated. There is no risk of furan formation in irradiated fresh-cut products (Fan).

    " Alternative technology relying on rachis removal, sanitization, hot water treatment and modified atmosphere packaging was found to maintain quality of clustered grape without need for sulfur dioxide to control decay (Luo).

    " A hybrid orange-fleshed melon was evaluated and found to be excellent for whole storage and also excellent in terms of shelf life and nutritional quality retention once transformed into fresh-cut cubes (Saftner)

    " A two stage approach (preharvest sanitizer spray, followed by postharvest chitosan coating) was found to significantly reduce decay in strawberries.(Narciso, Baldwin and Plotto)

    " A combined treatment technology has been developed and a patent application submitted. This technology controls ripening and microbial growth in intact and fresh-cut fruits and vegetables (Toivonen)

    " Humidity control combined with ethanol vapor improves quality retention of intact and fresh-cut cherries. (Bai)

    " Brown rot (Monilinia fructicola) was significantly reduced by a pre-packaging dip with saprophytic yeast (Cryptococcus infirmominiatum) and ethanol pads at 1 and 20°C, respectively. (Bai)

    Objective 3. Improve understanding of biochemical, physiological and molecular mechanisms that affect fresh-cut product quality.

    " The optimum ripeness stage for preparation of fresh-cut mango was investigated using fruit harvested at the same maturity stage (minimum SSC = 15%). Ripening was initiated by 24 h ethylene exposure and fruit were selected for slicing after progressively longer periods of ripening. Fresh-cut mango shelf life at 5C was determined to be better correlated with flesh color than with peel color, TTA, SSC or flesh firmness. The 46C water treatment required for phytosanitary purposes was found to have no significant effect on fresh-cut mango quality or shelf life. The response of fresh-cut versus whole mango fruit to chilling temperature (5C) compared to non-chilling temperature (12C) storage was investigated. Aroma retention was reduced by chilling.

    " Watermelon fruit were exposed to 1-MCP prior to storage as intact or fresh-cuts for 7 d at 10C. Respiration but not ethylene was significantly enhanced by cutting. Tissue from 1-MCP-treated fruit had higher 1-aminocyclopropane-1-carboxylate synthase (ACS) activity, suppressed respiration, and undetectable 1-aminocyclopropane-1-carboxylate oxidase (ACO) activity during storage. CaCl2 dips had little influence on ACS activity, but significantly enhanced ACO activity and maintained firmness of fresh-cut tissue during storage. 1-MCP treatment of intact watermelon is alone unlikely to benefit the storage duration of fresh-cut watermelon. (Huber)

    " Several tropical fruits including guava, mango, acai, and passionfruit, were shown to have a unique chemical makeup and that those chemical compounds provide health benefits related to their antioxidant and anti-cancer activities. Fractionation of these foods into related families of chemical compounds do not provide the same degree of health benefits as the whole food. Guava induces caspase-3 and caspase-8, two enzymes in the apoptotic pathway resulting in death of cancer cells. A dose related increase in caspase activity was shown. (Talcott)

    " Identification of a wound signalling compound in extracts of wounded lettuce leaves that stimulates phenolic metabolism in healthy, undamaged tissues. (Saltveit).

    " Randy Beaudry, Jeff Brecht and Elizabeth Baldwin have submitted a NRI proposal on enzyme and volatile of melons.

    " Randy Beaudry has initiated a project to determine the impact of atmosphere and temperature on the gene expression of sliced and whole tomato.

    " Jorge Fonesca evaluated the effect of UV-C, chlorine and hydrogen peroxide on key nutritional compounds of fresh-cut tomatoes.

    " New statistical correlation method (Trosset plots) applied to analyse two years of volatile and maturity data for melons (Beaulieu).

    " Solid phase extraction method developed for assessing volatile analysis of fresh-cut watermelon (Beaulieu).

    " The ratio of acetate to non-acetate ester ratios was confirmed as a good approach to interpreting flavour balance in fresh-cut melons and apples (Beaulieu).

    " Have identified two accessions from Kazak Malus spp. Which are immune to Penicillium. The quality and disease resistance of these accessions will continue to be studied.(Saftner)

    " Resistance to cut-edge browning was found to be low when Granny Smith apples were harvested two weeks or before the initiation of climacteric ethylene production (Toivonen).

    Objective 4. Standardize methods for recovering pathogenic and spoilage microorganisms from intact and fresh-cut produce including tree nuts.

    " A method using flow-through immunocapture with real-time PCR was developed and demonstrated for detection of several human microbial pathogens in selected foods within 8 hours. (Schneider)

    " A method involving flow cytometry and fluorescent molecular probes to rapidly detect Samonella in bean sprouts is being developed (Mendonca).

    " Confirmed that prior reports of reduction of volatile loss on exposure to UV light by cantaloupe cubes were not true. It is safe to use UV to treat cantaloupe since it has no inadvertent effect on flavor (Beaulieu).

    " MS Thesis collaboration completed, Allison Dumas, LSU, November, 2006. Antimicrobial Activity of CPC and ASC Against Foodborne Pathogens and the Physiological Effect on Fresh-cut Cantaloupe at Refrigerator Temperatures. (Beaulieu)

    " Developed a protocol to sample microbial populations on only the cut surfaces of fresh-cut product. This allows study of the effect of transfer of microbes from the peel to the cut surface during processing. (Narciso, Baldwin and Plotto).

    Objective 5. Evaluate and control unintentional and intentional microbial contamination of intact and fresh-cut produce.

    " Survival and growth of Bacillus atrophaeus and Salmonella spp. and effectiveness of sanitizer treatments in inactivation of Salmonella on fruit or vegetable surfaces was shown. (Bartz & Schneider)

    " Effect of last irrigation timing on the microbial populations on harvest lettuce was determined (Fonesca)

    " Antimicrobial phytochemicals with high volatility have been incorporated as coatings on fresh-cut produce or films. These compounds diffuse into the vegetable tissues and package headspace to control pathogenic and spoilage microflora (Avena-Bustillos).

    " Effects of food grade sanitizers in combination with irradiation are being investigated for synergistic control of microbial populations in fresh-cut fruit (Mendonca).

    " Mixtures of organic acids and surfactants are being evaluated for their effectiveness in killing human enteric pathogens on fresh produce and tree nuts.(Mendonca)

    " Acidified calcium sulfate and Sanova are effective at reducing microbial populations of whole cantaloupes without causing any detrimental effects on quality (Fan).

    " Hot water pasteurization of whole cantaloupes resulted in lower total plate counts in fresh-cut product made from heat-treated fruit and there was no negative effect on quality. (Fan).

    " Despite sanitation treatment, cantaloupe must be stored at low temperatures following treatment to suppress regrowth of any viable contaminant on the rind surface (Annous).

    " A pilot scale enhanced Biosafety Level Two containment facility for evaluation of produce disinfestations technologies has been validated (Annous).

    " Chlorine dioxide gas treatment was found to be effective at inactivating Salmonella attached to inaccessible site of cantaloupe rind or within biofilms. The treatment also reduced spoilage organism populations and did not have adverse effects on quality. (Annous).

    " Physiological and environmental factor studies have shown the nutrient composition along cut edges and package atmosphere interact and can affect pathogen virulence. (Saftner)

    " Ongoing recovery and isolation of non-pathogenic micro-organisms which are then assessed for potential antagonists activities against other microbes.

    " Conducted a study on the comparative microbial loads on various fruits and vegetables (cantaloupe, mango, citrus, potatoes and small fruits). (Narciso, Baldwin and Plotto)

    " Studies are showing that E. coli O157:H7 grows rapidly at 15 ºC on fresh-cut Romaine lettuce and slowly at 8 ºC. The growth at 15 ºC is variable, depending on the lot of lettuce. (Delaquis and Bach)

    " Starvation of E. coli O157:H7 and Salmonella can induce a viable but non-cultural state (VBNC). (Delaquis and Bach)

    " Studies are ongoing regarding survival of E. coli in dairy manure, soil, after transfer to Romaine lettuce and in fresh-cut Romaine. (Delaquis and Bach)

    " Review paper concluded that prevention of preharvest contamination is essential to minimize the risk of illness caused by consuming raw produce because Postharvest treatment of the produce with sanitizers cannot be relied upon to eliminate pathogens. (Beuchat)

    " Hypochlorite form (calcium or sodium salt) does not affect the level of microbial control or flavor of fresh-cut lettuce of diced tomatoes. (Beuchat)

    " Information on the effectiveness of various sanitizers on the killing of Bacillus spores on apple surfaces and stainless steel has been developed (Beuchat).

    " Survival and growth of Enterobacter sakazakii on fruits and vegetables and factors affecting growth and survival were documented (Beuchat).

    Impact Statements:
    1. Impacts: 1. S-294 scientists working in food safety have provided the fresh and fresh-cut fruit and vegetable industries with critical information resolve ongoing food safety issues which challenge existence of the industry.
    2. 2. S-294 scientists are investigating the potential commercialization of a sanitizer and sanitization strategy for use on fresh-cut fruit and vegetables with a US-based company already marketing a processing aid to the fresh-cut industry.
    3. 3. Members of S-294 have developed a food security audit program specifically for fresh produce growers and processors and fresh-cut processors in the Southeast U.S.
    4. 4. Members of S-294 have been co-authors of a while paper entitled Infections associated with cantaloupe consumption: A public health concern.
    5. 5. S-294 scientists are negotiating the licensing of a new combined release technology for controlling ripening and decay in fresh and fresh-cut products with a US-based company already marketing a ripening control product to the industry.
    6. 6. Several S-294 members participated in the United FreshTech Food Safety Symposium in April 2007, providing leadership to the industry on food safety issues for fresh and fresh-cut produce.
    7. 7. Several S-294 members participated in the Science Symposium and the Food Irradiation Workshops hosted at the United FreshTech Conference in April 2007.
    8. 8. The S-294 meeting attracted five produce and fresh-cut produce industry representatives, providing a forum for discussion of research priorities and how to develop better interactions between researchers and industry.
    9. 9. The S-294 members presented 19 posters at the United FreshTech trade show. These posters generated interest from industry and led to follow-up interactions with researchers.
    10. 10. Members from the USDA and the University of Florida developed and manned booths at the trade show, facilitating interaction with members of the fresh and fresh-cut produce industries.
    Last Modified: 07-Jun-2007

    Date of Annual Report: 05/04/2008

    Report Information:
  • Annual Meeting Dates: 05/04/08 to 05/04/08
  • Period the Report Covers: 10/2007 to 09/2008

    • Participants:
    Brief Summary of Minutes of Annual Meeting:
    The meeting convened at 9:45 a.m.

    Review of agenda - accepted as submitted

    In an introductory statement, the Chair thanked United Fresh for their support to the S-294 working group and helping organizing the meeting.

    In a welcome statement, Dave Gombas, United Fresh, emphasized how important research is to the industry, how industry turns to research for answers. He wishes to continue a long-term relationship with the research group. He then discussed the state of the industry, with mixed news. On the "good news" side, the industry has been working actively with Capitol Hill on the new Farm Bill to convince Congress to support specialty crops - may be as much as $230,000,000 for specialty crop research. Most of research emphasis is on food safety, but some support for diversity, sustainability, shelf-life and food quality research. On the negative side, the industry members feel they do not get all the support for the research: they need solution-based research. Even though S-294 helped organize the Science symposium, the industry does not feel they are getting an answer to their questions. One issue is in the area of food safety to set standards for produce handling: when they wanted to set food safety standards, they did not have the science base to set the standards. They need assessment of risks to understand microbial cycles. To overcome these difficulties, a research work group is starting this year. A prioritized list has been made: intervention strategies #1 priority - information on priorities found on website. John Beaulieu (LA) will assist in developing/coordinating research priorities on the Food Safety and Technology Council for UFPA. Additional notes of welcome and a description of eligibility of S-294 members for registration at UFPA were provided. Next year, the meeting will be held at the Venetian April 22-24.

    Some discussion followed with respect to the relationship between S-294 and industry: Jim Gorny: the comments about academia teaming up with industry is appropriate, however, the exchange needs to go both ways. It is important for scientists to understand confidentiality, and how to establish a trusting relationship between industry and research. Examples of positive relationship between industry and academia were given by Barry Eisenberg (River Ranch Fresh Foods) and Pat Millner (USDA,ARS).

    2007 minutes approval: Tabled until end of meeting to allow all to read the minutes.

    Reuben Moore, the Administrative Advisor, complimented the group for its productivity (publications and scholarly activity). Impact is usually greater when there are publications. The Farm Bill is good news for the group. Researchers will have to apply for grants through NSF, NRI or others to get some of these research dollars. He admitted that competitive grants do not have the same priorities than industry solution-based research, but he hopes the researchers follow through to the industry for results. About Create 21, a few of the components are still in the bill. However, the merger with CREES will not happen. Hatch funds will likely all go competitive, which will negatively impact multistate research projects in the future. He offered assistance if needed. Gorny asked about multistate research funds for travel to this project - 7 or 8 of the attendees indicated they receive travel funds. He noted that UCD did not allocate funds for travel and asked the group how funds were handled. Moore indicated that AES Director has discretion regarding travel and other support. Moore indicated he could find out how much Hatch $$ were sent to each land grant university and offered to send a letter to the Director of the Experiment Station.

    Election of new secretary. Bassam Annous nominated Mikal Saltveit. Carried unanimously.

    Planning 2009 meeting: Mendonca requested input for UFPA Science Symposium topics. He described current process for identifying topics. Beaulieu suggested that request for speakers go out at least 6 months prior to date of meeting (Sept/Oct). This does not exclude the possibility that an outbreak or crisis occurs, which will need to be addressed. Annous asked about inviting international speakers (example of FAO/WHO project looking at chlorine issues). Lefcourt suggested that technological issues may be more appropriate from in-country speakers. Gombas suggested no limits be placed on Symposium as long as it involves the best of the best research that we as top researchers think the UFPA needs. Gorny asked if UFPA had travel funds for speakers. Gombas indicated it was negotiable. Mendonca indicated that executive committee will take up the process earlier, 6 months prior to the meeting as suggested. Motion was made to this effect and carried.

    Brecht suggested the executive committee commit to updating membership list. Moore asked that those not on the list (he provided this) leave their name on the document. The membership list was passed around.

    Research Division - UFPA Beaulieu described his activities with the research division of UFPA and initiated a discussion of the relationship between UFPA and S-294. He indicated that UFPA directors group was large and unwieldy, so working groups were developed. There are now 5 working groups, one of which is the research division. The other four working groups are: education and outreach, microbiology, audits, and standards harmonization. The Center for Produce Safety at UCD will become a clearinghouse for research information; he indicated his interest in assisting that effort. He suggested the contacts with UFPA be utilized for various research-related agendas. He asked that S-294 provide some input as to his role with UFPA. Lefcourt mentioned the difficulty with getting growers (primarily growers) and people using equipment and other technologies used in the fresh produce industry. Gombas indicated that there really is a good deal of representation across the industry and that within the UFPA, there are 4 sectors: a grower shipper board, fresh-cut processors board, retail food service board, and whole food board. Each board will have their own issues/agenda. Gombas offered his resources to enable appropriate interactions and Beaulieu will work with all 4 groups. Eisenberg provided some descriptions of the realities of the disconnection between researchers and industry, especially with regard to timelines that we both work on. Lefcourt commented on the lack of industry financial support. Brecht reminded that S-294 was created to identify projects and pool our brains/resources to take it to the industry. He thinks the Research Division is a great improvement. He suggested UFPA act as a lobbying group to change funding structure at the governmental level. Gorny suggested the UFPA may provide letters of support for various projects. Moore indicated that government support likely will not directly address UFPA priorities. Gombas agreed, but described success in terms of investment on dollars spent via lobbying. Discussion ensued of the nuances of industry/scientist research relationships. Gombas noted that even political discussions are long-term. Lefcourt indicated there may be a risk regarding the Farm Bill not returning if impacts are not evident.

    News from UC-Davis: Gorny described the development of the Center for Produce Safety (Fernandez Exec. Dir.) at UCD including funding ($4.5M) from industry ($4.0M) and California Department of Food and Agriculture ($0.5M). They will have their first advisory board meeting on June 19th, and the Research Committee on May 23rd.

    Station Reports: Annous (USDA-ERRC)  NRI grant with UCD to develop effective treatments on leafy greens: They succeeded a 5-log reduction with chlorine dioxide, but noted visual quality effects. He also described surface pasteurization of cantaloupe using hot water (76.1°C for 3 min) and chlorine dioxide. They will take it to a pilot scale. Results are promising in terms of flora remaining. Also mentioned the development of recommendations published for a level 2 biosafety facility.

    Fan (USDA-ERRC) - Described use of 1 kGy radiation treatment to reduce E. coli on 13 commodities commonly used in fresh cut. No negative effects were apparent, but some improvement in decay reduction was noted. A reduction in vitamin C content in response to radiation was noted. Another project looked at reducing Salmonella on whole cantaloupe using chemical sanitizers.

    Hurst (UGA) - Described funding of $2M in awards to UGA from Fresh Express (from a total of $9M) for control of E. coli. He noted five different food safety studies on E coli O157:H7 underway. He described four projects underway by M. Harrison. The published activities regarding E. coli and Salmonella were described including E. coli transmission in ice and a non-pathogenic strain with similar attachment properties to pathogenic strain.

    Orton (Rutgers) - Has only had recent interest in fresh-cut research. Described activities and industries involved in postharvest area, noting that interest is waxing. He noted that a facility for business incubation (26,000 sq. ft.) for food proc. being built.

    Beaudry (MSU) - Looked into packaging of sliced melon and pear. There was no impact of MAP on color or texture of 'Rocha' pear (collaboration with Portugal), but it made a difference on melon. Other projects: Evaluation of gene expression of chilled and heat-treated tomato fruit. Look at the genes associated with the generation of aroma esters by using transformed yeast and Arabidopsis.

    DeEll (OMAFRA) - Reported on reduced browning apples and their potential for fresh-cut apples, including 'Eden'. Discussed slow-release 1-MCP in packages, which benefited sliced apple storage. She described a study evaluating "Empire" storage and internal browning: when 1-MCP was used, decay increased in short-term storage; however, 1-MCP benefitted in long-term storage. Noted work underway on the effect of thermal processing of fruit juices.

    Saltveit (UC-Davis)- Described simple (field) test for titratable acids using a filter paper similar to a litmus test for pH. Described method to measure CO2 efflux immediately after cutting.

    Mendonca (Iowa State) - Used electron beam irradiation to sanitize cantaloupe surface: it was more effective when used after a wash, and fruit surface still wet. Wetting with citric acid + surfactant improved log reduction due to washing and a subsequent radiation treatment. He also described efforts for detection of human pathogens. One method uses flow cytometry and fluorescent tagging.

    Plotto (USDA/ARS) - Described research with sensory panels on 1-MCP treated tomato, strawberries and citrus juice. She mentioned work going on to substitute a lab test for sensory panels. Peroxyacetic acid use in field enhanced long-term storage of strawberry. She described research on a new clamshell package (Bai).

    Beaulieu (USDA/ARS) - Has plans to begin work on amino acid metabolism as it pertains to aroma synthesis. He is establishing a new method or aroma measurements, using SBSE instead of SPME (more volatiles can be extracted from the sample - less variation due to the absorbent). He will start work on molecular techniques in collaboration with UCD, as they relate to aroma formation of melon and cucumber. Has intent to work on inhibition of ripening in MAP. Will begin work on E. coli contamination on spinach.

    Forney (Agrifood-Canada) - Evaluating/discriminating aroma impact of processing steps, packaging, and biological changes on onion, pepper, squash, and colored carrots. Challenges keep a low microbial load on butternut squash: incorporation of antimicrobial compounds such as microgard and potassium sorbate in edible coatings worked. Another project looking at volatiles involved fresh cut onions in packages made of PLA and found aroma was retained as long as the packages were non-perforated. He reported on studies underway looking at microbial ecology as it relates to food safety with projects including liquid dairy manure and potential bioterrorism agents. He reported on Toivonen's research: apple slices packaged in microperforated films had fruitier aroma when compared with slices in conventional solid films MAP. Research underway to slow-release ethanol using yeast and sugar, + MCP in packaging, might benefit many commodities.

    Lefcourt (USDA/ARS-BARC) - Described efforts evaluating human pathogens and food-borne illness. They develop genetically-labeled E. Coli to see if and how it is incorporated in the produce. They are primarily using spectroscopy with a goal to develop hand-held devices. Looking at developing probes for purposely contaminated foods for the military. Some efforts to try to scanning apples for contamination in real-time; reported that the capacity to do quality and contamination assessment is at commercial readiness. Looking at the use of Raman spectroscopy as a laboratory tool to detect virulent organisms. Also looking at fluorescence of the rate of quenching of chlorophyll that passed through E. coli gut.

    Brecht (UFla) - Described assay for browning to visualize PPO and phenolic distribution. Reported on expansion of digital image library for fresh cuts. Found that immature fruit tended to be more sensitive to hot water treatment-induced browning. Huber showed that 1-MCP reduced water-soaking associated with senescence and apoptosis-like events in senescing tissues. Found that hot-water treatments had a relatively minor impact on aroma and quality in mango  more impact when the fruit is immature. He presented Bartz data on use of RT PCR detection technique. Noted that high-temperature treatments did not stimulate spore germination of Bacillus (instead of Anthrax) and that ethylene did not enhance Salmonella proliferation.

    Woods (Auburn) - In cantaloupe, he found that hot water + irradiation delayed ripening as well as good microbial control. He found that low dose irradiation directly applied to cut cantaloupe had an adverse effect on carotenoids. A significant reduction in contamination by Salmonella was found. Is now evaluating the impact of peeling on sweet potato quality. Attempts will be made to improve mandarin orange segment storage and appearance.

    End presentations

    Discussion:

    Brecht asked about industry acceptance of irradiation treatments. Fan described recent workshop on concerns and challenges remaining for implementation. Gombas mentioned that consumer resistance may still be significant ad that cost is a significant issue. Mendonca described advantages of irradiation on leafy greens in packages, especially with regard to E. coli and its susceptibility to radiation under moist conditions. FDA approval still somewhat of an obstacle. It was noted that incoming product quality had to be high. Right now, it is cost-prohibitive because of the logistics of the treatment.

    New Business:

    There was a motion to keep the S-294 meeting before the UFPA meeting. S-294 meeting to be scheduled on April 21st, 2009, at 9:00 a.m. 2009 meeting is again here in Vegas. Next years CA Conference and Postharvest Conference are in Turkey in the first two weeks of April.

    A Gordon conference on Plant Senescence will be held in June 2008.

    Saltveit noted that the final version of the Handbook 66 is at the editors.

    Brecht noted that the attendance at the S-294 is declining, and lack of funds is an issue. He suggested that a regularly scheduled conference call be developed to enhance interaction, attendance, and planning and offered to organize it. Beaulieu suggested he will take the request for support of the call by UFPA. This was moved (Beaulieu, Beaudry) and motion carried. Milner suggested UFPA contact land grant university deans to lobby for their making unit involvement a priority. Gorny suggested that National Program Leader on the topic area be included on the call. He provided an update on progress on strategic planning for vegetable industry.

    Saltveit (Beaulieu) moved acceptance of the minutes as they are. Motion carried.

    Motion to adjourn (Saltveit, Beaudry) carried (4:30 pm).

    Accomplishments:
    Objective 1. Develop, evaluate, and standardize subjective and objective quality evaluation methods in intact and fresh-cut fruits and vegetables.

    . The catechol and nitroso visual assays of Kader and Chordas (1984) were adapted using fresh-cut mango slices to visualize the distribution of PPO and phenolics, respectively, within the mesocarp. (Brecht-FL)

    . Digital images of several fresh-cut products were associated with previously developed rating systems for inclusion in the database developed by project participants at UC Davis. (Brecht-FL)

    . Methods for comparing analytical and sensory methods of analysis of tomatoes and oranges are on-going. (Baldwin and Plotto-ARS-FL)

    . A sensory panel was trained to evaluate tangerine juice from a breeding trial. 54 hybrids were studied by sensory evaluation and volatile analysis, sugars and acids. (Baldwin and Plotto-ARS-FL)

    . A sensory panel was trained to study of flavor and aroma profiling of 1-MCP treated versus non-treated tomatoes. The same sensory methodology will be used to study chilling effect on stored tomatoes (Baldwin and Plotto-ARS-FL)

    . Untrained/consumer panels were performed to evaluate new selections of strawberries. A briefly trained panel was performed to compare results with consumer panels (Baldwin and Plotto-ARS-FL)

    . A method was developed to easily measure the acid content of commodities in the field (Saltveit-CA).

    . A new method of volatile analysis using SBSE (sorptive bar solid extraction) instead of SPME (solid phase micro extraction) is being developed to analyze volatiles in cantaloupe (Beaulieu-ARS-LA)

    Objective 2. Develop new strategies to maintain fresh-cut product quality

    . The effects of the mango hot water quarantine treatment on the visual and compositional quality factors, aroma volatile production, respiration rate, and electrolyte leakage of fresh-cut Kent mango slices stored at 5°C for 10 days was investigated. The results suggest that the quarantine hot water treatment does not significantly affect the quality or shelf life of fresh-cut mango. (Brecht -FL)

    . New packaging was designed that significantly decreases weight loss of fruit and nearly doubles the fruits shelf life in cherry, strawberry and blueberry fruit. (Bai & Baldwin-ARS-FL)

    . Post-cutting shelf life and nutritional quality were evaluated for kiwifruit, pineapple, cantaloupe, strawberry, mango and watermelon stored at 5 °C. Light exposure promoted browning in pineapple pieces and decreased vitamin C content in kiwifruit slices, but increased in mango and watermelon cubes (Kader-CA)

    . Incorporation of antimicrobial compounds in starch-based edible coatings in combination with MAP increased the shelf-life of fresh-cut squash. (Forney & Fan-Canada)

    . Aroma of fresh-cut onion and apples is strongly affected by packaging. Research is in progress to understand mechanisms of action of packaging and internal atmosphere on flavor retention. (Forney, Fan, Bezanson-Canada/ARS-PA)

    . Effect of cutting and dipping treatments on quality, volatile recovery, SEM surface appearance, and freshness in cut melon (Beaulieu-ARS-LA)

    . Respiration behavior of fresh-cut pears under modified atmosphere and different temperatures was studied. Data provided a basis to predict package permeability to gases and will help choosing optimum MAP and temperature combinations to prevent anaerobic conditions and maximize shelf-life of fresh-cut pear. (Beaudry-MI)

    . Cut pears were treated with ascorbic acid, sodium hexametaphosphate, and calcium chloride solutions. Response to treatments on texture and color varied according to which cultivar was used, Kiefer Seedling, Beurre D'Hardenpont, or Passe Crassane. (Pilizota- Croatia)

    . Two strawberry cultivars were treated with different concentrations of H2O2, ascorbic acid, citric acid, K-sorbate, or CaCl2 and in different combinations. After 12 days at 4 °C, colour was best maintained with 2.5 % AA, 2.0 % CA, and 2.0 % K sorbate, and texture with 2.5 % AA and 2.0 % and 2.5 % K-sorbate (Pilizota  Croatia) . The effect of low-dose electron beam irradiation (0, 0.5 and 1.0 kGy) on fruit quality (pH, % citric acid, Brix and total carotenoid content) and populations of Salmonella was studied on fresh-cut cantaloupe stored at 5oC for 12 days. In general, there was no adverse effect of irradiation at low dosage. However, at higher dosage (1.0 kGy), undesirable changes in quality and antioxidant levels may occur. (Woods & Mendonca-AL/IA)

    . Irradiation technology is being evaluated to know whether it should be used exclusively in whole fruit prior to fresh-cut process or post sanitizing methods. (Woods & Mendonca-AL/IA)

    . The effects of 1 kGy radiation on the quality of thirteen common fresh-cut vegetables was investigated: Iceberg, Romaine, green and red leaf lettuce, spinach, tomato, cilantro, parsley, green onion, carrot, broccoli, red cabbage, and celery. In general, there was no difference in appearance, aroma and instrumental texture between irradiated and non-irradiated samples for most vegetables. When there were differences between samples, appearance was often improved by irradiation. The vitamin C content was similar for most vegetables, except that irradiated green and red leaf lettuce had 24-53% lower vitamin C contents than the controls. (Fan - ARS-PA)

    Objective 3. Improve understanding of biochemical, physiological and molecular mechanisms that affect fresh-cut product quality.

    . The role of ethylene-action in quality changes and shelf-life of intact versus fresh-cut melon fruit was investigated using pretreatment with 1-methylcyclopropene (1-MCP). Inhibition of ethylene action by 1-MCP reduced tissue watersoaking, improved firmness retention, and suppressed electrolyte leakage. The development of watersoaking or tissue translucency was accompanied by an accumulation of lipases, carbohydrate-degrading enzymes, and up-regulation of genes encoding these and other, unidentified proteins. (Huber-FL)

    . The apparent lack of chilling injury symptom development in fresh-cut tropical and subtropical species in terms of more basic physiological responses of the tissues to chilling stress such as textural alterations and aroma volatile production is being investigated using whole and fresh cut Kent mangoes stored at chilling (5°C) and non-chilling (12°C) temperatures. Aroma volatile did not differ among whole fruit and fresh-cut slices stored 5 or 12 °C with the exception of ethanol, which was lower in whole fruit and slices stored at 5°C. There was no difference between storage temperatures for electrolyte leakage. Reduced ascorbic acid content and increased softening at 5°C suggest that the fresh-cut slices did experience chilling stress (Brecht -FL)

    . A model was devised to segregate the efflux of CO2 from segmented tomato fruit into the four components previously described to measure the contribution of each component to the efflux measured. A substantial, but transient increase in CO2 efflux occurred immediately after segmentation. The rate of efflux did not return to the initial rate but stabilizes at a slightly elevated rate presumably caused by increased respiration resulting from enhanced diffusion of oxygen into the tissue. This method should allow isolating wound-enhanced respiration from other respiratory changes brought on by altering the diffusion of gases into and out of the segmented tissue. (Saltveit-CA)

    . Identification of the wound signal in fresh-cut lettuce and measures of physical and physiological effects of wounding on the rate of carbon dioxide efflux are two major studies under progress. (Saltveit-CA)

    ‡. Effects of the last irrigation schedule, nitrogen fertilization and sunlight prevalent during the week prior harvest were studied on the quality parameters of intact and fresh-cut lettuce processed in lab and commercial settings. Also, studies are performed involving the effect of sanitizing treatments on chemical/nutritional composition of fresh cuts. (Fonseca-AZ) ‡. Bioaccessibility, a measure of what components are soluble and therefore available for absorption in the gut after digestion, is measured for antioxidant fractions in fresh cut fruit and vegetables. A method for performing an in vitro digestion of tissue has been developed. Subsequent to digestion, the samples are fractionated to evaluate the antioxidant value of phenolic and non-phenolic fractions of digestate. Results to date indicate that slices from different cultivars of apples have differing characters and that they may show differing responses to application of anti-browning dips. The bioaccessibility of antioxidant constituents is only a fraction (up to 30%) of what is extractable using solvent extraction. This work will help to better quantify relative biological value of fruit or vegetable tissues, based on what can potentially be absorbed as opposed to the current solvent extract analyses which indicate what is present in the tissue before digestion. (Toivonen, Delaquis, Bach & Bezancon-Canada)

    . A new project was recently funded to study postharvest flavor loss of whole and fresh-cut fruit and vegetables. The effects of atmosphere modification, interactions with packaging materials, and postharvest treatments on flavor will be assessed to determine mechanisms of flavor loss and develop technologies to preserve flavour (Forney, Fan & Bezancon-Canada).

    . Research is under way to determine how and why certain Cucumis melo melons (climacteric, western shippers, eastern shippers, Charentais, Peil de Sapo, Galia etc.) are considered highly aromatic whereas other melons like Cucumis inodorus (non-climacteric, honeydew, casaba, some LSLs) are considered non-aromatic or have low volatile production. Methods include amino acid analysis, analysis of volatile precursors, and enzyme assays. (Beaulieu-ARS-LA)

    . The apple cultivar Eden has reduced browning upon cutting but is chilling sensitive. Optimum storage conditions need to be determined in order to have these fruit available to industry throughout the year. Studies on Eden under various storage regimes in 2007-2008 were not conclusive. Additional years of postharvest studies are needed to better understand this cultivar and to develop successful storage recommendations. (DeEll & Toivonen-Canada)

    . Agriculture and Agri-Food Canada developed a 1-MCP-based new technology (NT) for the packages of fresh-cut apple slices that substantially reduced decay development in all cultivars evaluated. The NT treatment also improved firmness and reduced color change in apple slices, but the level of effect was dependent on cultivar and time in post-slice storage at 5ºC. (DeEll & Toivonen-Canada)

    . Storage conditions, pre-storage treatments and maturity at harvest (temperature, time, atmosphere, MCP or DPA treatments) of whole apples affected quality of slices made from stored apples. For short-term CA stored apples, fruit from earlier harvest resulted in slices with less decay than later harvests or fruit treated with MCP. For long-term storage, apples treated with MCP or DPA resulted in slices with less decay and browning. In addition, a few days of holding apples in refrigerated ambient air after CA storage improved slice quality. (DeEll & Toivonen-Canada)

    Objective 4. Standardize methods for recovering pathogenic and spoilage microorganisms from intact and fresh-cut produce including tree nuts.

    . A method using flow-through immunocapture (FTI) with real-time PCR was developed and demonstrated for detection of several human microbial pathogens on smooth tomato surfaces and in potato salad and ground beef within 8 hours. Food samples were inoculated with an appropriate dilution of a five-serovar Salmonella cocktail and enriched for 5 h. Following enrichment, samples were analyzed by the FTI-XLD and FTI-PCR methods. Food samples were also analyzed by a modified U.S. Food and Drug Administration Bacteriological Analytical Manual (BAM) Salmonella culture method for comparison. The FTI method demonstrated the ability to isolate presumptive Salmonella colonies up to 48 h faster than did the modified BAM Salmonella culture method. (Schneider-FL)

    . The ecology of human enteric pathogens in packaged fresh horticultural products is being studied using spinach/lettuce and Listeria/E. coli 0157 surrogates as model systems. Conventional culture based methods, in vitro enhancement/inhibition assays, fluorescent-stain microscopy, and microbial community profiling are being used to determine the role of plant tissue, its condition (whole, cut) and its native bacterial population in the colonization, persistence, and multiplication of human pathogens on vegetables. (Bezanson et al.-Canada)

    . Novel microbiologic and molecular methods to assess the safety of leaf lettuce are being evaluated through lab and field studies designed to detect and estimate the persistence of fecal contamination events by monitoring variations in the ratios of atypical to total coliform or fecal bacteria present on spinach and lettuce and the relative proportions of six major E. coli genotypes on plant tissue and in irrigation water and soil (Bezanson, as part of a team funded by the Ontario Ministry of Agriculture, Farming and Rural Affairs-Canada)

    . In a program exploring spectroscopy techniques for detection of trace bacteria and biological toxins in foods, efforts continue to develop a Surface Enhanced Raman Spectroscopic (SERS) method as a rapid and routine detection technique, and to fabricate and characterize SERS nano-probes to provide localized and non-destructive SERS identification on surfaces of bulk samples. (Lefcourt, Kim & Chao-ARS-MD)

    . Efforts continue in development of sensing technologies for detection of evidence of bacterial and bioagent contamination on food surfaces. Primary targets of interest are produce and food preparation areas. (Lefcourt, Kim & Chao-ARS-MD)

    . Development of technologies screening and sorting apples with evidence of fecal contamination. Work continues on the orientation track system: when apples are rolled down a track consisting of two parallel rails, they move to an oriented position where the stem/calyx axis is perpendicular to the direction of travel and parallel to the plane of the track. In addition to the ability to orient apples, the track system could be used to transport apples during processing, thus replacing the current commercial conveyor systems. Work also continues on developing imaging systems and detection algorithms to simultaneously identify quality problems and contamination of apples during processing. (Lefcourt, Kim & Chao-ARS-MD)

    . A method involving flow cytometry and fluorescent molecular probes to rapidly detect Samonella in bean sprouts is being tested (Mendonca, Boylston, Brehm-Stecher, Reitmeier & Wilson-IA)

    . A method was developed, combining a simple adhesive tape-based method of surface sampling with fluorescence in situ hybridization (FISH) for the rapid detection of Salmonella spp. on tomato surfaces. Salmonella spp. were easily detected on tomato surfaces in less than 2 h, with a sensitivity of 103 - 104 Salmonella cells per cm2. Additional enhancement in sensitivity was obtained after short (8 hr) solid-phase enrichment on selective (XLT-4) agar. This proof of concept work highlights the potential for tape-FISH to provide rapid, cost-effective and specific detection of Salmonella spp. on fresh produce surfaces, even in the presence of non-target organisms such as saprophytic yeasts. (Mendonca, Boylston, Brehm-Stecher, Reitmeier & Wilson-IA)

    . While stomaching samples dilutes the microbial population, but includes any that have penetrated into the flesh, washing samples results in less dilution, but may miss some microbes that penetrate the flesh. Surface washes of cut products are preferred at the US-CSP lab. (Narciso, Baldwin & Plotto-ARS-FL).

    Objective 5. Evaluate and control unintentional and intentional microbial contamination of intact and fresh-cut produce.

    . Survival and growth of Bacillus atrophaeus and Salmonella spp. and effectiveness of sanitizer treatments in inactivation of Salmonella on fruit or vegetable surfaces was shown. The effect of moist heat treatment on infesting bacterial endospores was investigated. Recovery studies suggested a less than 2-log10 unit reduction of inoculated B. atrophaeus spores after a 3-minute, 85ºC moist heat treatment, and no heat injury symptoms developed on cantaloupe melons during storage for 2 weeks at 5ºC. Increasing treatment temperature from 75 to 95ºC resulted in no increase in efficacy in terms of recovery of indigenous vegetative bacteria. The results suggest that aqueous heat treatment is not a suitable method for reducing populations of the resting structures of spore-forming bacteria from the surface of netted muskmelons. (Schneider&Brecht-FL)

    . The effect of ethylene on the survival of Salmonella cells residing on unwounded surfaces of tomato fruit was investigated. Fruit were held at 20ºC and 95% relative humidity after surface inoculation with the low virulence and rifamycin-resistant pathogen S. enterica ssp. enterica serovar Typhimurium strain LT2 (S. Typhimurium). Tomato fruit were treated either with air or with 150 ppm ethylene in air. The results suggest that although Salmonella can survive on the surfaces of tomato fruit in typical ripening rooms, proliferation of Salmonella is neither promoted nor inhibited by ethylene exposure. (Schneider&Brecht-FL)

    . New strawberry selections were evaluated for post-harvest decay. The effect of genetics on strawberry shelf-life was obvious. On the other hand, some selections, very sensitive to rain damage, could be improved post harvest by growing under protected cultivation. (Baldwin, Plotto & Narciso-ARS-FL)

    . Effect of preharvest practices and irrigation water quality and subsequent intervention mechanisms are examined on microbial population of harvested product (Fonseca-AZ)

    . The effect of different sanitizers on the reduction of Escherichia coli O157:H7 and Salmonella on baby spinach leaves was studied. Inoculated spinach leaves were subjected to a water wash followed by treatment of one of the following sanitizers: 2% lactic acid at 55 C, calcium hypochlorite, peroxyacetic acid, ozonated water, or chlorine gas. The reductions of E. coli O157:H7 and Salmonella on spinach leaves were similar to each other and the sanitizers had an average log reduction of 1.1 CFU/g. The treatment that produced the greatest bacterial reduction was lactic acid. This treatment significantly reduced E. coli O157:H7 by 2.7 and Salmonella by 2.3 log cycles. (Castillo-TX)

    . The reduction of inoculated E. coli O157:H7 and Salmonella on baby spinach by the application of e-beam irradiation was tested. Inoculated samples as well as controls were exposed to 0.79, 1.16 or 2.48 kGy electron beam irradiation and stored for 8 days at 4 C. For E. coli O157:H7, the log reduction was 4.1, 6.3 and 6.4 log CFU/g when irradiated at 0.79, 1.16 and 2.48 kGy, respectively. For Salmonella, 0.79 kGy resulted in 4.0 log reduction, and 1.16 or 2.48 kGy irradiation reduced initial counts of 7.3 log CFU/g to below the detection limits (< 10 CFU/g). Irradiation did not affect the survival of the remaining microorganisms stored over eight days (P < 0.05). (Castillo, with collaboration of the Wintergarden Spinach Producers Board and the Texas Produce Association-TX)

    . The impact of wounded generated oxygen radicals on microbial survival and growth will be assessed using both biochemical analyses and confocal microscopy. Initial studies are planned to quantify and localize the production of hydrogen peroxide on cut surfaces over time, after processing. The data generated will allow analysis of the impact of measured hydrogen peroxide levels on specific bacteria in culture systems. Subsequent analysis will be performed, using confocal microscopy to determine whether chronological changes in bacterial populations can be directly associated with levels of hydrogen peroxide. (Toivonen & Pascal Delaquis-Canada).

    . Studies will be continued to determine the fate of E. coli from manure in soil and Romaine lettuce on two experimental sites. Sampling strategies and methods for the recovery of E. coli from lettuce and soil will be adjusted for seasonal differences in plant development and rates of survival for the target bacteria in soil. Test plots will receive liquid dairy cow manure in the spring at least 90 days before planting. Generic E. coli and VTEC populations in manure, soil and on lettuce plants will be determined. Lettuce will be examined for internalized E. coli; other samples will be cut, washed and packaged to examine the fate of E. coli during processing and storage of the crop. Isolates will be retained for characterization to examine the association with and persistence of specific genotypes in each sampled environment. (Delaquis, Bach & Bezanson-Canada)

    . The assessment and management of risk to human and environmental health from microbial contamination from animal and human wastes is being assessed through soil and plant applications of liquid dairy manure and naturally contaminated irrigation water to romaine lettuce plots. Standard and chromogenic-media detection and quantification coupled with isolate DNA typing are being used to follow migration, colonization and persistence rates of E. coli under field conditions (Bezanson et al.-Canada).

    . A project titled Mitigating dissemination of bioterrorism agents in Canadian food systems was recently funded by the Canadian Department of National Defense Research and Technology Initiative Program. A part of this project will assess the stability and behavior of candidate surrogate bacterial, viral and protozoan strains in soil, water and romaine lettuce plants. Selected strains will be introduced via inoculated liquid dairy manure and irrigation water. Substrate optimized isolation, enrichment, and concentration protocols will be developed to provide material for surrogate detection and quantification via culture, immuno-magnetic separation and quantitative PCR-based methods. Trials will be duplicated in BC using different soils, microclimates, plant and cultivar. (Bezanson et al.-Canada)

    . Research has been conducted on the efficacy of washing Romaine and Iceberg lettuce with chlorine solutions, and acidic electrolyzed water containing 50 ppm chlorine to reduce surface contamination with E. coli O157:H7. None of the wash treatments studied thus far have yielded a log reduction significantly greater than that achieved by simply washing the lettuce with deionized water. Chlorine dioxide gas was tested to reduce surface contamination of Romaine lettuce with E. coli O157:H7. No significant log reduction was observed at the concentration-time tested, however less browning of treated leaves over the 8 days of treatment was observed as compared to leaves which were not treated with ClO2. Further research is currently underway to investigate the efficacy of different concentration-time exposures with chlorine dioxide gas. (Annous & Keskinen-ARS-PA)

    . Research was conducted on lettuce plants watered with E. coli O157:H7 to determine the possible uptake of the microorganism by the edible portions of the plant via direct plating and via scanning electron microscopy. It was determined that this method of artificially contaminating plants would not be ideal for initial studies evaluating the effectiveness of inactivation of internalized E. coli O157:H7 due to the low numbers of bacteria that are taken up by the plant, if any. (Annous & Keskinen-ARS-PA)

    . Spinach inoculation study are underway, collaborator with LSU, Beilie Ge: Interaction of Escherichia coli O157:H7 with Growing Spinach Plants (Beaulieu-ARS-LA)

    . It was found that ice made from water contaminated with E. coli O157:H7 can spread the pathogen to other heads of romaine lettuce in a shipping container as the ice melts. (Harrison & Kim-GA)

    . It was determined that lettuce leaves or roots grown in soil contaminated by E. coli O157:H7 or Salmonella spp. did NOT internalize the pathogens. Conversely, these pathogens on the surface of the lettuce leaves were quickly internalized. (Erickson, Doyle & Beuchat-GA)

    . The methods of attachment on romaine lettuce by non-pathogenic E. coli ATCC 25922 was studied. This non-pathogenic strain of E. coli would be a useful surrogate for E. coli O157:H7 for studies involving attachment and recovery from chilled produce. (Harrison & Kim-GA)

    . Studies to determine how Salmonella attaches itself to raw Roma, round and grape tomatoes. Salmonella grew in the stem scar and pulp tissues of all three varieties of tomatoes at 12° and 21°C, but not at 4°C. It would not grow on the skin of grape tomatoes at any temperature. (Beuchat & Mann-GA)

    . The effect of washing practices at Georgia cantaloupe packing houses on microbial contamination is being examined. Although hot water sanitizing was slightly more effective than chlorinated dump tanks in reducing counts, temperatures in the dump tanks could not be sustained. Microbial populations on melons increased slightly after removing melons from the dump tank, suggesting post-process contamination after washing. (Hurst & Harrison-GA)

    . In a project to determine subsurface contamination and internalization of E. coli O157:H7 in pre-harvested lettuce, studies will determine (1) strain differences among E. coli O157:H7 isolates to internalize, colonize, survive and grow on and in lettuce plants; (2) the degree of internalization of E. coli O157:H7 and its subsequent survival and growth in different types of lettuce and at different phases of the plants growth cycle; (3) the role of environmental stress (heat or water) and soil fertility on the level of internalization of E. coli O157:H7 in lettuce; the effect of level of contamination on the extent of internalization, colonization, and survival/growth of E. coli O157:H7 in and on lettuce plants; (5) the effect of insect damage to lettuce leaf tissue on internalizing E. coli O157:H7 and its subsequent survival/growth; (6) survival and possible internalization of E. coli O157:H7 in lettuce as a function of location of contamination (abaxial or lower leaf surface vs. adaxial or upper leaf surface); (7) the contribution of soluble organic matter (simulating materials in which E. coli O157:H7 can be found) on survival of E. coli O157:H7 on lettuce surfaces; and (8) the level and site of contamination of iceberg lettuce when cored by an E. coli O157:H7-contaminated knife. (Doyle, Beuchat & Erickson-GA)

    . In a project to determine the fate of E. coli O157:H7 on fresh and fresh-cut iceberg lettuce and spinach in the presence of normal background microflora, studies will (1) determine the ability of E. coli O157:H7 to multiply in the presence of normal background microflora on iceberg lettuce and baby spinach; (2) simulate commercial conditions and practices for handling spinach and lettuce to allow the evaluation of the fate of E. coli O157:H7 on produce during typical handling operations; (3) isolate naturally-occurring microorganisms that may be present on spinach and lettuce under different handling conditions that may show inhibitory activity toward E. coli O157:H7; and (4) provide insight into how E. coli O157:H7 interacts with naturally-occurring microflora on lettuce and spinach such that the knowledge can be used in analyzing what produce handling and packing routines might be beneficial or detrimental in reducing contamination related to this pathogen. (Harrison & Hurst-GA)

    . Research is being conducted on applying food grade chemical sanitizers, and low dose irradiation for killing pathogens on the skin surface of cantaloupes to reducing contamination of the fresh-cut fruit. Hydrogen peroxide, selected surfactants or organic acids, alone or in combination, are being tested for destroying human enteric pathogens on cantaloupe, apples, lettuce, seed sprouts and almonds. Sequential applications of various chemical sanitizers and electron beam irradiation are also being evaluated to destroy pathogens on the outer rind surface of cantaloupe. (Mendonca, Boylston, Brehm-Stecher, Reitmeier & Wilson-IA)

    . Research is in progress to determine the fate of pathogens on the outer rind surface of cantaloupe and whole apples following sequential application of chemical washes and low dose irradiation. (Mendonca, Boylston, Brehm-Stecher, Reitmeier & Wilson-IA)

    Impact Statements:
    1. S-294 scientists working in food safety have provided the fresh and fresh-cut fruit and vegetable industries with critical information resolve ongoing food safety issues which challenge existence of the industry.
    2. Knowledge generated from studies is being used by S-294 scientists in outreach activities for a change in attitude among students towards food safety in general, and food irradiation as an environmental-friendly and safe alternative for food safety.
    3. S-294 scientists received two of nine Fresh Express competitive research grants awarded in May 2007. This funding targets studies on E. coli O157:H7 contamination of spinach and iceberg lettuce.
    4. S-294 scientists are looking for industrial partners to commercialize the patent pending technologies of orienting apples based on their inertial properties.
    5. S-294 scientists submitted a utility patent application for a hyperspectral/multispectral linescan imaging system that can simultaneously acquire reflectance and fluorescence images using a single camera. Industrial partners are sought to develop the technique at a commercial level.
    6. S-294 scientists have signed an agreement with an industrial partner to develop a commercial surface enhanced raman spectroscopy detecting instrument and for collaboration on imaging technologies.
    7. S-294 scientists are working with an industrial partner to develop a hand-held device to survey food processing areas for detection of bacterial and bioagent contamination on food surfaces.
    8. S-294 members organized the United FreshTech Science Symposium in May 2008, providing leadership to the industry on food safety issues for fresh and fresh-cut produce.
    9. The S-294 working group has been involved in the discussions with the Research Division of the UFPA. Research priorities and how to develop better interactions between researchers and industry are being discussed.
    10. The S-294 members presented 15 posters at the United FreshTech trade show. These posters generated interest from industry and led to follow-up interactions with researchers.
    11. S-294 member are collaborating with industry. Example: Wintergarden Spinach Producers Board
    Last Modified: 18-Jul-2008

    Date of Annual Report: 04/21/2009

    Report Information:
  • Annual Meeting Dates: 04/21/09 to 04/21/09
  • Period the Report Covers: 10/2008 to 09/2009

    • Participants:
    Brief Summary of Minutes of Annual Meeting:
    The meeting convened at 9:17 a.m.: there was a round of introductions

    Review of agenda - Diana Barrett made a motion to accept the meeting agenda, seconded by Ann Lefcourt and passed

    Approval of 2008 minutes: The minutes were discussed and a few changes and additions suggested. Changes and correction will be sent to Anne Plotto. Alan Lefcourt made a motion to accept with revisions; seconded by Diana Barrett and passed.

    Introductory statement: The Chair thanked United Fresh for their support to the S-294 working group and helping organizing the meeting.

    Reuben Moore, the Administrative Advisor: He said we must maintain NIMS website because it is the site viewed by evaluators. Names must be updated: there are 57 participants currently listed on the website. Project summary is on the web. Next year is the termination, so the termination report and the project must be rewritten by September 2010. Need objectives that people are working on.

    S-294 was nominated for award excellence. Great publication record and deserves recognition for the great work. Need better acknowledgment of collaboration for award

    Question of HATCH funds available for travel. All land grant universities get HATCH funds. These funds may go all competitive, but not a good idea since many small projects will not be adequately funded. Twenty-five percent of HATCH funds must be spent on multi-state activities. S-294 is an approved multi-state activity, so the experiment station administrators should be made aware that funds should be made available for travel and multi-state activity. However. he noted that UCD did not allocate funds for travel and asked the group how funds were handled. Moore indicated that AES Director has discretion regarding travel and other support.

    Ratings by NSF of agriculture expenditures were UCD was #1 for many years, but last year (2007) Florida was #1: UCD was #2, with George #3, and, Texas A&M #4.

    There is not much spending on agriculture in the stimulus bill, so we must hang in through these tough economic times until things turn around.

    Diana Barrett asked how productivity is gauged. Supporting grants and published papers in referred journals are used in evaluating productivity. Not many people are receiving speciality crops grants, but not all the grants have been awarded.

    Ram Rao: CSREES Representative: He suggested that we focus on outcome of research; how can this group contribute to solve important practical problems.

    He discussed the future direction of research and showed a set of slides with a lot of information outlining the changes that were occurring in the Agriculture and Food Research Initiative (AFRI) replaced National Research Initiatives. The slide set will be made available to S-294 members.

    On October 1, 2009, the name was changed to National Institute of Food and Agriculture (NIFA). CSREES authorities will be incorporated into NIFA and a new head appointed to a 6-year term by the President. Its authorization will be increased from 500 to 700 million. CSREES is developing vision, mission goal and core values for the new organization

    He briefly described the change from 4 NRI topics to 6 AFRI topics. He listed competitive grants programs that could be of interest to S-294 members. 1. NIFSI National integrated food safety initiative ($14.7 M). 2. Agriculture and food research initiative (AFRI - previously described above) ($9.0 M). 3. Higher education grants; Nanotechnology portfolio; and Improved food quality and value (Basic and applied research in food quality). Small Business Innovation Research (SBIR): Food safety and nutrition (Phase I: Explore novel ideas ($80 K), development phase ($350 K). 4. Specialty Crop Research Initiative (SCRI) must have 100% non-federal matching funds. Work with stake holders from formulation of problem to completion. Multi-state and multi-institutional (231 applied 27 awarded). The five areas we may be interested in are 1. Threats from pests and disease, 2. Production efficiency, 2. New technology, and 4. Prevent detect monitor control respond to potential food safety hazards.

    Dave Gombas: made the following comment: UFFV is not pleased with SCRI because research did not result in solutions to problems, but just concluded that additional research was needed. He did not know where the matching funds part would come from. He is heartened that the direction of research is to answer practical problems and that advisory boards are being asked their priorities. He stated that many stake holds are hungry for researchers to answer their problems. Mikal Saltveit inquired if there is a website where researchers could contact stake holders to initiate mutual research. Diana Barrett asked about matching funds. Matching funds are dictated by congress and there is not much room for flexibility.

    Dave Gombas: He welcomed us and emphasized how important our work was to the industry. He said that the industry does not do any research and relies on us to answer practical problems.

    There are 17 registrants and 15 poster presentations. The posters will be setup at 12:00 and viewed for 3 to 6 on Wednesday. The applied research shown in posters is just what the industry wants done. Mikal Saltveit was selected to represent S-294 as one judge.

    There will be two breakout sessions and the science symposium on Wednesday. The meeting next year will be here at about same time; April 20  23, 2010.

    Discussion: In a discussion that followed, recommendations were made to improve the interaction between members of S-294 and UFPA. While UFPA has no money for research, the industry representatives at the show are interested in discussing possible collaborations. Since the meeting deals with both fresh-cut and whole produce, the question was raised if S-294 should also address whole produce. Bill Hurst commented that the objectives of S-294 are mainly for fresh-cut, but some of the objectives also are to do with whole produce. There was general agreement to modify the objectives of the rewrite to include whole fruits and vegetables. Alan Lefcourt asked if there was still a reason to separate pre and post harvest. Discussion was that there is increasing blurring of the distinctions. We should market the s-294 to include more members and to expand the base to include other specialties to broaden our research base

    New secretary: Mikal Saltveit nominated Jeff Brecht, seconded by Sunny (Yaguang Luo) Jeff was unanimously elected. There was some question about his duties and it was concluded that past officers will be involved in writing the termination report and the rewrite of the new project.

    Topics for Science Symposium: Alan Lefcourt suggested the topic oc biofilms as they have been responsible for a few disease outbreaks. Discussions during the conference call included many industry representatives (around 40) who listened to the discussion about the topics and speakers for the science symposium. How can we get better communication between industry and researchers? Diana Barrett talked about the "speed dating" to get UCD academics to talk to industry representatives for 15 min each. Dave encouraged S-294 members to interact with UFP members at the beach party this evening.

    Station Reports:

    Alan M. Lefcourt (USDA, Environmental Microbial and Food Safety Laboratory ARS, Beltsville) - She described the development of a rapid screening method for bacteria using colloidal silver. Online imaging methods were also presented for apple inspection for quality and contamination with fecal material.

    Anne Plotto (USDA, ARS, CSPL, Florida) - Laser etching of fresh produce did not increase decay of water loss from citrus, peppers or tomatoes. Tested alkaline surface washes on whole fruit to reduce microbial contamination of fresh-cut. Studied the use of heat treatments to reduce the impact of chilling injury on volatile production and flavor of tomatoes.

    Aubrey Mendonca (Iowa State University) - Studied effective way for the control and detection of pathogens in fresh produce. Anionic acidic solutions were effective at reducing pathogen levels on peppers. High pressure treatments were better at reducing pathogens moist than on dry nuts.

    Bill Hurst (University of Georgia) - Listed the personal changes in the microbiology group during the past year. Vapor treatments with three antimicrobials were effective in controlling pathogens on sliced and whole tomatoes. System studies determined the fate of E. coli O157:H7 on fresh and fresh-cut iceberg lettuce and spinach from harvest to packaging. Naturally micro floras were identified that inhibited E. coli. The effectiveness of the concentration and duration of exposure to various sanitizers on controlling cross-contamination was evaluated. Methods were studied to eliminate surface pathogens in studies of internal microbial contamination. These methods were used on studies on internalization in lettuce, spinach, and leafy greens.

    Diane Barrett (University of California, Davis) - Effect of heat, high pressure and pulsed electrical fields on integrity of onion tissue. Instrumental methods to determine textural properties of watermelon in the field. Development of new methods to determine mold in tomatoes.

    Eva Almenar (Michigan State University school of packaging) - The effect of packaging and temperature were studied on the aroma compounds from fresh-cut romaine lettuce.

    Jeff Brecht (University of Florida) - There was interest in reported results that Salmonella bacteria can grow on fresh cut tomatoes at 7 to 10 C. There was a discussion of the need for data on temperature of displayed fresh-cut and the design of display cases to maintain the correct temperature.

    Jennifer DeEll (OMAFRA, Ontario Ministry of Ag) - Postharvest treatments of whole apples to reduce browning of fresh-cut slices. Maturity had a significant effect as did the holding time after CA and before slicing. Browning increased in fruit held at lower temperatures (chilling injury?), those treated with 1-MCP, and those sliced sooner after CA than those held for 7 days in air..

    Bo Beaulieu (USDA, ARS, Southern Regional Research Center) - Continued his work on quantifying volatile components in melon, and how they change during CA and MAP storage. Cantaloupe cultivars were evaluated for volatile production. Extend work to berries.

    Marita Cantwell (University of California, Davis) - Described the 3-day workshop on Fresh-cut produce at UCD: the next is on September 22-24, 2009. Described how ammonia can be used as an indicator of stressful atmosphere for intact and fresh-cut vegetables. Evaluated methods to control browning of processed potatoes. Evaluated a range of modified atmospheres on packaged vegetable trays. Evaluated various treatments for microbial control on fresh-cut cantaloupe. Studied the effect of modified atmospheres on ascorbic acid content of fresh-cut lettuce.

    Mikal Saltveit (UC Davis) - Presented an update on hand-book 66. Outlined methods to measure titratiable acidity in the field. Instruments were assembled to exam the efflux of carbon dioxide from fresh-cut fruits and vegetables in order to resolve the sources: 1) carbon dioxide dissolved in cellular fluids, 2) carbon produced by immediate enzymatic and non-enzymatic reactions, and 3) carbon dioxide produced by induced increases in metabolism. Studies were also undertaken to examine changes in the anaerobic compensation point of fruits and vegetables with maturity and duration of storage.

    Roger Stanly (Primary Industries, Queensland, Australia) - Presented studies on anti browning coatings, coatings to maintain active compounds below phytotoxic levels, studies of maintain volatile from tropical fruit under cold storage, adding volatiles back to improve quality, and NMR to select maturity of mango and tomato for fresh cut.

    Xuetong Fan (USDA, ARS, ERRC) - Anti-browning and anti-microbial properties of sodium acid sulfate were evaluated on apple slices. Treatments that were effective in reducing flesh browning caused skin browning. Studied the tolerance of lettuce and spinach to radiation. Studied the effect of various commercially available formulations to reduce contamination on cantaloupe.

    Yaguang Luo (USDA, ARS, BARC Food quality lab) - Natural micro-flora can compete with E. coli. Temperature abuse can cause product deterioration and a rise in E coli to dangerous levels, however, E coli can survive in presence of large natural micro-flora and grow faster that natural micro-flora; e.g., grow 2 log when product still looks good.

    Studied the transference of contaminate with knifes and the effect of tissue damaging in field core lettuce. Coring knife can be a source of microbial innoculum because of poor weld connecting the blade with the handle has small holes where the bacteria colonize. Studied internal microbial contamination: contamination goes down stem scar to about 1.5 cm into the fruit. Removal stem scar and columella would only reduce 3 % of fresh weight, but would greatly reduce contamination.

    Yanyum Zhao (Oregon State University) - Effects of decontaminating high hydrostatic pressure on the activity of enzymes associated with reduction in quality of blueberries. Coatings were studied that will reduce water loss in vented clamshell containers.

    Yong Li (University of Hawaii, Manoa) - Use PCR to finger print microbial contamination

    New Business (Plans coordination efforts, grant proposals deadlines,etc.) Many people expressed interest in collaborating on research projects. John Beaulieu suggested having the reports distributed earlier so we could come here to discuss collaborations and not just read the reports. There could be a site where we could share ideas and initiate collaborations. Mary Reid maintains the site where S-294 could be used to exchange information within the group.

    Bo Beaulieu suggested that more S-294 members become members of UFPA. Only members of UFPA ($250) can be on the food tech and safety committee. UFPA strength is in their lobbing efforts to get money into our research rather than fund the research themselves. Other institutes and trade associations fund research, but it appears to be a historical. Could the UFPA act as a clearing house where S-294 members would write a short proposal and then a consortium of a few businesses would come together to fund that project. Funding match maker to fund research to get preliminary date to write grants for specialty grants. A successful mechanism to get funding for research to answer a problem and create a useful product.

    Bo Beaulieu proposed a motion to form a taskforce to formulate possible methods to get UFPA to act as a clearing house to bring together scientists and funding sources (industry) to support research. The taskforce will be made up of Jeff Brecht, Alan Lefcourt, Xuetong Fan, and Bo Beaulieu.

    It was suggested to have the next meeting a day before the UFPA next year (April 19, 2010).

    The final rewrite of S-294 is needed by August 31 2010. Jeff Brecht proposed to have a draft of the rewrite sent in early so that it can be distributed and read before the meeting so we can devote the time to more constructive activities.

    The meeting was adjourned at 4:51

    Accomplishments:

    Impact Statements:
    Last Modified: 02-Mar-2011

    Date of Annual Report: 03/01/2011

    Report Information:
  • Annual Meeting Dates: 04/20/10 to 04/20/10
  • Period the Report Covers: 10/2009 to 09/2010

    • Participants:
    Brief Summary of Minutes of Annual Meeting:
    The meeting convened at 8:12 am with a welcome by Anne Plotto and a round of introductions.

    Review of agenda - the agenda of the 2010 meeting was approved by voice vote without discussion.

    Approval of 2009 minutes - the 2009 minutes were approved by voice vote without discussion.

    Remarks from Dave Gombas, UFPA Vice President - Dr. Gombas discussed how United wants to foster engagement between scientists/students and industry members. He suggested that UFPA needs an official liaison from S-294. He further suggested creating a forum for scientist-industry communication, maybe a research advisory board with the structure to be determined later. Gombas stated that the industry can help identify both immediate & long term research needs for S-294. Regarding funding for such research, Brecht suggested that S-294 propose to AFRI a conference grant for a symposium with industry.

    Report from the Administrative Adviser, Reuben Moore - Dr. Moore discussed the budget situation at Land Grant Universities and ARS.

    Remarks and presentation about SCRI by CSREES Representative, Ram Rao - Dr. Rao reported that the SCRI grant program has been transferred to NIFA. AFRI was authorized at $700 million - he discussed the approach by AFRI in prioritizing research in terms of the focus, scale, and impact. There will be five program areas, including Food Safety. Dr. Rao indicated that AFRI expects greater collaborations and stakeholder involvement. There will opportunities for larger grants (up to $25 million) and greater duration (5 yr).

    SCRI was approved with $230 million of mandatory funding for 2008-12; project must include both research and extension, with priority going to multi-state/multi-institutional projects; there must 100% non-federal matching funds; proposed projects must address critical needs of the specialty crops industry. Focus areas (at least 10% to each) 1. Breeding/genetics; 2. Pests/diseases; 3. Production efficiency/product/profit. 4. Innovation and technology; 5. Food safety (food safety has been the least funded - including food safety in your proposal increases the chance of funding).

    NIFSI 2010. Integrated approach (2/3 RTE); from theory to practice. Priority: 1. Education & training for all stakeholders; 2. Safety of fresh and fresh-cut fruits and vegetables. Zeroed out for 2011 and $$ shifted to AFRI.

    Planning for the 2011 meeting - The next UFPA Fresh Summit convention will be in New Orleans, May 3-5. It was agreed that S-294 should meet prior to that on May 2.

    Election of new Secretary - Charles Forney was nominated and unanimously elected as Secretary for 2010-11.

    Poster Competition - The topic of discussion was whether to continue this tradition or discontinue it. There was discussion of the effectiveness of posters in communicating research activities to Fresh Summit attendees from industry; Lefcourt mentioned lack of promotion in program. UFPA is trying something new this year by having a discussion area and has scheduled scientists to discuss their work. Brecht suggested working with UFPA to come up with more innovative approaches, e.g., video posters. Suslow suggested submitting abstracts of proposed research in addition to reporting on completed research.

    Science Symposium -Plotto mentioned previous topics that have been covered in Science Symposia. She suggested as a topic, targeted nutrition based on individual genome. Rao mentioned the Childhood Obesity priority area related to nutrition and FFV. Cantwell suggested the interaction of sensory quality and nutrition. Lefcourt suggested exploring socioeconomic aspects of FFV consumption. Beaulieu suggested the effect of sanitation treatments on flavor and nutrition. These ideas and others suggestions from the S-294 participants will be communicated to UFPA during preparation for the 2011 Fresh Summit.

    Station Reports Details of these reports are available in the annual reports posted at http://postharvest.ucdavis.edu/S294

    FL - Brecht reporting. FL contributed to the quality rating scales compiled by Kader and Cantwell (CA). A MAP system was developed and tested for fresh-cut mango at higher temperatures. Best practices for application of aqueous 1-MCP were determined for tomato and carambola (carambola work in collaboration with ARS-FL). Responses to low temperature stress (tomato) and ethylene-mediated stress (cucumber and watermelon) were investigated. It was determined that the quarantine heat treatment being applied to mangoes does not affect fresh-cut quality, if the fruit are not unripe when treated. Common fresh-cut mango handling temperature of 5°C reduces aroma synthesis, but still is better for maintaining adequate shelf life than higher temperatures.

    ARS-FL - Plotto reporting. ARS-FL is continuing to use experienced consumer and trained descriptive panels and chemical analysis to evaluate strawberry and tomato germplasm from FL. Post-cut dipping of carambola with Ca-ascorbic acid reduces browning, maintains texture, and reduces sour, astringent and bitter tastes. Sanitizing blueberries with acid sanitizer does not remove bloom; coatings with volatile oils reduce decay and sweeten the fruit. Antioxidant responses in tomato, orange and carambola challenged with chilling or heating were investigated; tomato volatiles and flavor in response to heating and chilling were studied.

    ARS-MD - Lefcourt reporting. Improvements are continuing to be made with industry collaboration on an on-line multispectral detection system for apples that covers both quality and safety tasks. Work has been initiated with an industry partner on development of a handheld sanitation inspection device. A transportable hyperspectral imaging system for detection of pathogens on apples was developed with US Army. FT-Raman spectroscopy was used to detect melamine in meal and flour samples. Working on theoretical aspects of fruit orientation during movement.

    ARS-LA - Beaulieu reporting. SPME and Tenax trapping are being used to recover pomegranate volatiles. Amino acid profiles are being surveyed for berries and juices. Measuring pomegranate polyphenolics. Measuring blueberry composition, including volatiles. Volatiles from cantaloupe and honeydew melons in CA and MAP were compared. Collaborated with LA on testing for E. coli on spinach and Salmonella on other produce.

    MI - Beaudry and Almenar reporting. The quality and microflora of fresh-cut Romaine lettuce in polypropylene versus poly(lactic acid) packages was compared and found to not differ. The dynamics of volatile evolution following tissue cutting or disruption was characterized for apple, showing that differing kinetics of production/degradation for different compounds likely influences flavor perception.

    BC - Bach reporting. A protocol was developed to measure oxygen radicals and quinones on cut surfaces of Romaine lettuce. Work with E. coli was performed related to persistence and survival on and around leafy greens. Assessed the VBNC state of human pathogens on leafy greens under different conditions.

    NS - Forney reporting. Lactic acid bacteria and bacteriocins, and MicroGARD® 730 are being evaluated as bio-preservatives and antimicrobials for fresh-cut vegetables. The influence of packaging on the flavor retention of fresh-cut apple slices and whether aeration of CA stored apples can enhance the flavor of fresh-cut apple slices was determined. Volatile compounds responsible for apple and blueberry flavor are being identified and characterized. Effects of cutting on respiratory metabolism and volatile production of fresh fruits and vegetables are being determined. The role of metabolic and diffusional mechanisms contributing to the loss of aroma and flavor of fresh-cut produce is being assessed using carrots and apples as model systems. A novel protocol for the recovery, enrichment and confirmation of carriage of verotoxigenic E. coli other than serotype 0157:H7 by intact field-grown Romaine lettuce was assessed and modified. The possibility that E. coli-contaminated irrigation water and liquid dairy manure may serve as reservoirs of enteric pathogens for field grown spinach and lettuce is being assessed. Variation in ratio of typical to atypical coliforms and relative incidence of E. coli phylogenetic groups is being evaluated as a means of estimating time and source of fecal contamination of field-grown Romaine lettuce.

    GA - Hurst reporting.

    CA - Cantwell and Saltveit reporting. The 2nd edition of Produce Quality Rating Scales and Color Charts was completed. Ammonia was evaluated as a MA stress indicator in a range of fresh and fresh-cut vegetables in comparison to fermentative volatiles. The best handling conditions for fresh-cut specialty Brassicas are being determined. The performance of lettuce cultivars, including Iceberg x Romaine hybrids, as salad-cut products was compared. Work has continued to study the wound signal that initiates increased phenolic synthesis and tissue browning in lettuce. The signal has been partially characterized as a product of lipid breakdown. Research is underway to characterize the sources of carbon dioxide evolution form fresh-cut lettuce and tomato, which appear to be, in order, 1) out-gassing, 2) carbon dioxide produced upon decompartmentalization, and 3) increased respiratory system capacity.

    HI - Brecht reporting for Li. The stability of DNA in dead Salmonella cells was studied in order to develop an approach for detecting viable Salmonella cells on lettuce. DNA from the dead cells was found to remain intact on lettuce for at least 8 days. Propidium monoazide (PMA), a dye that can selectively bind to DNA of dead cells and prevent its amplification by PCR, was combined with real time PCR to selectively detect only viable S. Typhimurium on lettuce. The detection limit of this method on lettuce was approximately 103 CFU/g, or 101 CFU/g after 12 h of enrichment.

    Termination report - Brecht reported that the Termination Report for 2005-2010 will be due in March 2011, after the project end date. Plotto will write the Termination Report after soliciting member input on the most important accomplishments and impacts. Discussion ensued on the meaning of results, knowledge used, actions, and conditions. It was agreed that adoption of new practices by industry and marketing of new fresh-cut products would be great examples.

    New 5-year Project Proposal - Brecht reported that there is an August 31st deadline for submitting a new project proposal in order to avoid a gap in the project. He presented the draft project outline and discussed what has been done so far. After some discussion, it was decided to remove molecular activities. Objective 1 was re-written to cover comparison of methods and to include nutrition. Suslow volunteered re-write Objective 4. Brecht agreed to circulate a draft within one week of the meeting and to solicit modifications and indicate who will work on which areas. Ten potential peer reviewers were suggested.

    Brecht instructed the Participants that they will need to sign in again to participate in the new project. When signing in, it will be necessary to indicate a percent activity, it is recommended that not exceed 25%. The University Administrator/Experimental Station has to approve institutional and individual participation; the Administrative Advisor for the project must also approve participation. There was a question about who approves for ARS folks. The group has to let members know that they need to re-register.

    Brecht suggested that, for the new project, we should propose an SCRI grant to cover collaborative activities and annual meeting travel.

    New Business - None.

    The meeting was adjourned at 3:00

    UFPA will pick up the tab for food and beverage service. Thank you UFPA!

    Accomplishments:

    Impact Statements:
    Last Modified: 02-Mar-2011

    Date of Annual Report: 07/13/2011

    Report Information:
  • Annual Meeting Dates: 05/02/11 to 05/02/11
  • Period the Report Covers: 10/2010 to 09/2011

    • Participants:
    Brief Summary of Minutes of Annual Meeting:
    The meeting was convened with a welcome by Mikal Saltveit and a round of introductions.

    Review of agenda  the agenda of the 2011 meeting was approved by voice vote.

    Approval of 2010 minutes - Change to the Michigan State University report were noted. John Bealieu then moved and Eva Almenar seconded the approval of the 2010 minutes, which was approved unanimously.

    Report from the Administrative Adviser, Reuben Moore  Dr. Moore stressed the importance to do a rewrite of the S-294 project, which is the most productive project of the 5 projects he advises. The project is currently under a 1 year extension. Jeff Brecht is chairing the rewrite. Anne Plotto was thanked for compiling the termination report for the past 5 years. Dr. Moore discussed the current budget situation and observed that federal funding has become more competitive based and less supportive of capacity.

    New 5-year project proposal, Jeff Brecht  A timeline for submitting the re-write of our project proposal was distributed. The rewrite must be submitted by May 13, 2011 by downloading it into NIMSS. Jeff has a draft that is missing some parts in food safety. He will email a draft to everyone asking for volunteers for items missing in the outline. If no interest is shown, areas can be removed and the draft can be submitted as is. A shift in emphasis to include whole produce in addition to fresh-cut was suggested. Names of people willing to serve as reviewer of the project proposal were collected. We have received special allowance to retain our S-294 designation if approval is received from NIFA by September 15, 2011. The project has maintained an association with United Fresh for 12 years and maintaining the S-294 designation was felt to be important to retain industry recognition.

    Termination Report  Anne Plotto prepared a termination report for the past 5 years. However, since the project was extended 1 year the termination report is not due until the end of this year. Jeff Brecht will look after submission of this report.

    Remarks and presentation about SCRI from NIFA Representative, Ram Rao  Dr. Rao provided an update on the funding programs in the Specialty Crops Research Initiative (SCRI). The 2012 farm bill is currently being formed and he indicated that there were opportunities for input. Available grant programs are posted on the NIFA web site.

    Opportunities for conference/planning grants to support S-294 research interests were discussed. Grants of up to $50K to support workshops, conferences or development of research proposals are available within different programs. Dr. Rao will send us additional information on these funding opportunities.

    Current funding limitations being a problem for scientist to attend S-294 meetings were also discussed.

    Election of new secretary - Eva Almenar was nominated and unanimously elected as Secretary for 2011-2012.

    Remarks from UFPA Vice President, Dave Gombas - Dr. Gombas thanked the group for their participation including the poster presentations that help to communicate research results and new innovations to the industry. He encouraged our continued interaction with the industry and expressed interest in a more formal relationship with United Fresh. Dr. Gombas suggested that he could help to coordinate the development of research grant proposals and facilitate industry collaboration. He is available to aid in soliciting industry input for projects. To facilitate greater interaction with industry he suggested that video conferences could be arranged. As industry research needs arise, he also offered to communicate them to the S-294 group.

    Science Symposium  A science symposium, which has traditionally been well attended in past meetings, will be part of the United Fresh 2012 meeting. Topics for the symposium were discussed. Alan Lefcourt suggested the topic of risk analysis. He suggested that there is poor understanding of risk in the industry and it would be a timely topic to address how science can be used to assess risk. Additional topics will be solicited by email.

    Poster competition  It was noted that this year there would be no competition among the scientific poster presentations.

    Station reports  Details of these reports are available in the annual reports posted at http://postharvest.ucdavis.edu/S294.

    ARS-MD  Lefcourt reporting. A multi-task online fruit inspection technology was upgraded to increase line speed in collaboration with industry partners. A Raman chemical imaging system is being developed for analysis of food samples. A hand-held image-based sanitation inspection devise is being upgraded and commercialized. A hyperspectral fluorescence imaging method has been utilized to detect bacterial biofilm formation.

    MI  Almenar reporting. The effects of primary packaging, sanitizers and heat treatments on the marketable quality of fresh peeled yellow onions were characterized. Antimicrobial films made from natural resources are being developed and evaluated. The role of lipoxygenase gene expression on aroma biology during apple fruit maturation was characterized.

    ARS-LA  Beaulieu reporting. Volatile compounds found in several pomegranate and rabbiteye blueberry cultivars at different maturities have been characterized. Attempts to look at secondary volatile genesis in these fruit is in process. Methods for the analysis of polyphenolics including anthocyanins in these fruit have been developed.

    CA  Saltveit reporting. Wound induced responses were found to increase the susceptibility of fresh vegetables to microbial growth. Altered metabolism associated with tomato heat shock is being studied. The mechanisms of increased carbon dioxide release as a result of cutting fresh produce is being determined.

    FL  Brecht reporting. Procedures to maximize quality of fresh-cut mango were developed. Hot water quarantine treatments did not affect quality of fresh-cut slices stored at 5 C. Modified atmosphere of 2.5 kPa O2 plus 10 kPa CO2 prolonged shelf-life of fresh-cut mangos 1 day at 15C but shelf-life was superior at 5C. Wound induced respiration and ethylene production was studied in Romaine lettuce. The effects of hot water treatments and pH of rinse solutions on browning of potato slices was determined. High internal ethylene concentrations inhibited the effectiveness of 1-MCP in tomato fruit. Responsiveness of cucumber and watermelon to ethylene was also explored. The effectiveness of chlorine dioxide gas, ozone, and chlorine in reducing Salmonella on cut tomato are being evaluated. The impact of laser labeling and various handling conditions on the survival of E. coli O157:H7 and Salmonella on whole and fresh-cut produce are being studied.

    NS  Forney and Fan reporting. The effectiveness of lactic acid bacteria, bacteriocins, and MicroGARD® 730 on the microbial populations and quality of fresh-cut vegetables was evaluated. Modified atmosphere packaging extended the shelf-life of diced red onions. The effectiveness of aeration of apples following CA storage on flavor of apple slices is being determined. The effectiveness of hydrogen peroxide to enhance shelf-life, nutrient quality and microbiological quality of fresh-cut spinach is being assessed. Aroma active volatiles produced by apples and high bush blueberries are being determined. Novel protocols for assessing carriage of verotoxigenic E. coli other than serotype O157:H7 in intact Romaine lettuce are being developed. Evaluation of sources and survival of E. coli contamination on field grown lettuce and spinach are being conducted. BC  Bach reporting. Biochemical and physiological characteristics including oxygen radicals and quinones of lettuce and their effects on pathogen physiological state and survival are being determined. Studies are being conducted to assess the biochemical mechanisms underlying the effects of post-controlled atmosphere aeration of whole apples on the subsequent quality retention of fresh-cut apple slices. Methods to detect viable but non culturable E. coli O157:H7 and Salmonella are being optimized. PCR phylogenetic grouping schemes are being used to detect changes in the diversity of E. coli following applications of manures. The persistence of commensal and pathogenic E. coli in various matrices such as soil, manure and lettuce is being evaluated. A system based approach for the assessment of risks associated with infectious organisms in food is being demonstrated.

    Italy  Colelli reporting. Modified atmosphere packaging, anti-browning agents and cultivar variation are being assessed for their effects on the shelf-life of fresh-cut artichokes, potatoes, bell peppers and broccoli raab. The effects of temperature and exogenous ethylene on the postharvest performance of purslane leaves are being assessed. Image analysis of cut surfaces is being conducted to quantify surface browning. Changes in external appearance using multispectral image analysis are being correlated with internal quality parameters in apples, pineapples, and melons.

    ARS-MD  Lester reporting. Studies are being conducted on the volatile composition of pepper cultivars and polyphenol content of eggplant. Radical scavenging in fresh-cut produce is being assessed as a natural microbial defense mechanism. The effectiveness of free chlorine in wash solution was assessed for its effectiveness in decontaminating and prevention of cross-contamination of lettuce with pathogens. The effects of light and photosynthesis on the vitamin content of lettuce is being assessed.

    USDA Handbook 66  Saltveit reported that Handbook 66 will be going to press with the addition one chapter on 1-MCP. It has been proposed to be available on line with all other online publications.

    New business

    A Motion was made by Jeff Brecht and seconded by Eva Almenar that with each station report there be a listing of current and future research relevant to the S-294 project to be circulated to all members to foster collaboration. The motion was passed unanimously.

    Dr. Rao encouraged us to strengthen our impact statements in our annual reports. He noted that progress of the project will be judged on: Outputs  results including, publications, patents, etc. (generation of knowledge)

    Outcomes - where the knowledge has been applied

    Impact - extent of use, long term effect, effect on society. Impact is a long term effect and may require some speculation.

    Next years meeting will be held in conjunction with UnitedFresh 2012 in Dallas, Texas

    Meeting adjourned at 2:35

    Our thanks to UFPA for providing food and beverage service and a room for the meeting. Thank you UFPA!

    Accomplishments:
    Objective 1. Develop, evaluate, and standardize subjective and objective quality evaluation methods in intact and fresh-cut fruits and vegetables.

    " Continuation of experienced consumer or trained descriptive panels and chemical analysis (volatiles, sugars, acids) to evaluate strawberry and tomato germplasms from University of Florida. 10-years of tomato data are being analyzed to establish a model for tomato quality.

    " Study interactions of limonin and nomilin, two bitter compounds in oranges harvested from trees having Huanglongbing (citrus greening) disease, and their effect on orange and orange juice flavor.

    " Quality evaluation of fresh-cut products through visible and multi-spectral image analysis.

    Objective 2. Develop new strategies to maintain fresh-cut product quality

    " Fresh blueberries are field packed and subject to exposure to food and decay pathogens that are passed directly on to the consumer because the fruit are not cleaned. Preliminary studies with blueberries show that sanitizing the berries with an acid sanitizer does not remove the bloom and coatings with volatile oils reduce decay and sweeten the fruit.

    " Fresh blueberry field sanitation or nutritional treatments to increase fruit quality at harvest.

    " Determine optimum harvest time for new mandarin cultivars.

    " Testing of new clamshell design that reduces water loss of small fruits without increasing decay, thereby extending shelf life

    " Optimum conditions (pH, culture media, and temperature) for LAB growth and bacteriocins production were determined. Heat stability, molecular weight and bacteriocins activity was investigated.

    " The addition of selected LAB to fresh-cut salads and diced onions inhibited the growth of yeasts and molds, Pseudomonas sp. and total coliforms naturally occurring on fresh-cut vegetables. LAB also significantly inhibited the growth of L. innocua inoculated on fresh-cut salads and diced onions.

    " Synergistic effect of MicroGARD® 730 incorporated in NatureSeal® PS-10 was found. Treatments with 0.5 or 1.0% MG plus 2.5% NS were recommended to treat fresh-cut squash prior to storage at 4°C.

    " Heat treatment times for boiling and steam were determined in relation to microbial quality and browning of fiddleheads.

    " Diced red onions packaged in sealed polylactic acid (PLA) containers reduced rates of microbial growth compared to vented packages but dips with Potassium sorbate or ClO2 had no significant effects.

    " The effect of aeration of CA stored apples in increasing concentration of flavor esters was dependent on cultivar and duration of aeration.

    " Ester content of immature Jonagold apples subjected to heat treatments of 4 or 8 h at 46 °C increased about 2-fold 24 h after treatment, but 12 h treatments or treatments on more mature fruit reduced ester content. No enhancement of ester content of Cortland apples was observed regardless of heat treatment duration or fruit maturity.

    " Volatile terpene content of carrots decreased with increased nitrogen fertilization in the field and with early harvest.

    " Survey of suitable varieties of Artichokes, Potatoes and Peaches for fresh-cut processing

    " Optimal gas compositions identification to be applied during storage of fresh-cut broccoli raab and artichokes

    " Postharvest performance of Purslane leaves in relation to temperature and ethylene

    " Postharvest management activities for fresh-cut bell peppers

    " Definition of optimal MAP for high convenience Kiwifruit

    " PLA pouch along with SAS performed the best in maintaining freshness in the peeled onions based on physicochemical, microbiological and sensory results. The SAS sanitizer successfully reduced bacterial growth but not yeast and fungal growth and was better at reducing bacterial growth than the FV sanitizer. The PLA pouch successfully reduced microbial growth and outperformed the PE pouch. Interactions between sanitizers and packaging materials can cause off-odor development.

    " Better understanding of impact of weather factors on nutritional quality and shelf life of leafy greens.

    " Clear panorama on how labor workers may influence quality and safety of leafy greens

    " A ripeness stage equivalent to an initial fruit firmness of 30 N was the optimum for processing Kent mangoes into fresh-cut slices.

    " The hot water quarantine treatment applied to whole, mature Kent mangoes did not significantly affect the quality of the fresh-cut slices stored at 5C.

    " Extremely rapid deterioration of fresh-cut mango at non-chilling temperature was not overcome by MAP, meaning that storage at a lower, putative chilling, temperature such as 5C should be recommended to achieve optimum quality retention.

    " The relative changes in CO2 production and O2 consumption that occur in the 24 hours after cutting suggest that non-respiratory oxidative reactions play a significant role in the post-cutting wound response of fresh-cut Romaine lettuce.

    " Hot water treatment prevented the synthesis of total soluble phenols in fresh-cut potato slices. A 24 hour delay between hot water treatment and potato processing reduced color changes of the fresh-cut product during storage at 5C for 6 days. "

    Objective 3. Improve understanding of biochemical, physiological and molecular mechanisms that affect fresh-cut product quality.

    " Volatiles derived from fatty acid oxygenation and the oxylipin pathway related enzymes were studied for gene expression and enzyme activity levels in tomato fruit. Chilling tomatoes reduced aroma volatiles, gene expression, and in most cases, enzyme activity for lipoxygenase, hydroperoxide lyase and alcohol dehydrogenase whereas heating had the opposite effect.

    " Tomatoes stored or treated with either low or high temperatures were evaluated for flavor using trained descriptive panels and chemical analyses.

    " Several polyphenolics in an acidified assay protocol have been recovered in pomegranate and blueberry, and we are capable to separate out the anthocyanins (glycosylated) versus the hydrolyzed anthocyanidins (sugar free) in a single run.

    " It appears that browning inhibition in fresh-cut potato by citric acid is due to a mechanism other than acidification  possibly its ability to act as a copper chelating agent in the active site of PPO. It is possible that HNO3 and H2SO4 similarly reduce browning by chelating copper rather than by reducing the solution pH.

    " Results from 1-MCP work are consistent with the hypothesis that fruit internal ethylene levels are capable of directly influencing the responses of fruits to 1-MCP. These findings could lead to improvement of commercial techniques for applying 1-MCP to fruits at advanced ripening stages and/or that accumulate high IEC.

    " Cucumber fruit were shown to exhibit markedly different developmental features in their ethylene responsiveness.

    " An ethylene-specific nuclease was identified that increases markedly during continuous ethylene exposure and it may play a role in programmed cell death in cucumber fruit.

    " The watersoaking response of immature cucumber and watermelon fruits to ethylene is serving as a model for studying the deterioration of fruits harvested at immature stages of growth. Our working hypothesis is that commodities harvested immature (e.g., cucumber, okra, summer squash) exhibit atypical senescence pathways that are more appropriately viewed as forms of programmed cell death.

    " Ethylene treatment of watermelon fruit induces watersoaking and also the appearance of a number of enzymes with activity toward xyloglucan, the major matrix polysaccharide in watermelon fruit tissue. Cell wall degradation and watersoaking in ethylene-treated watermelon fruit was accompanied by downshifts in mol mass of hemicelluloses mediated by several xylogucanase proteins.

    " Data from studies of low-temperature stressed tomato fruit with down-regulated levels of polygalacturonase indicate that pectin dissolution is PG-independent even though the enzyme is catalytically active in ripe fruit. Low-temperature storage reduces in vivo pectin solubility, an effect that is reversed upon transfer to higher temperature following cold storage. "

    Objective 4. Standardize methods for recovering pathogenic and spoilage microorganisms from intact and fresh-cut produce including tree nuts.

    " Assessment of the VBNC state of human pathogens on leafy greens which may have not been detected by conventional microbiological methods and which may contribute to foodborne illness.

    " Availability of a procedure enabling the isolation of a broader spectrum of verotoxin-forming E. coli from plant and soil samples should provide a better estimate of occurrence (and persistence) of enterohemorrhagic E. coli in agricultural environments, as well as assessment of health risk associated with non-O157 VTEC.

    Objective 5. Evaluate and control unintentional and intentional microbial contamination of intact and fresh-cut produce.

    " Protocols were developed for sanitizing citrus fruit for fresh juice sales using an integrated method.

    " ARS/EMFSL hyperspectral linescan imaging systems were optimized for in-line imaging to improve and enhance means for safety/quality inspection and sorting of fresh produce at high processing speeds.

    " ARS/EMFS portable imaging devices enable real-time detection of contaminated food processing surfaces, thereby reducing risks of cross-contamination. Portable imaging devices can be used by small processing plants for on-site sanitation/contamination inspection.

    " Increase fundamental knowledge about the effect of oxygen radicals and quinones in fresh-cut produce on human pathogens.

    " Identification of effective hurdles to the presence, persistence and survival of pathogens in order to develop effective intervention strategies for leafy greens.

    " Hydrogen peroxide concentrations and exposure times optimal for retention of leaf quality and control of microbial spoilage during spinach storage have been delineated; their effectiveness in reducing surrogate pathogen densities is being determined.

    " E. coli O157:H7 inoculated onto the leafy portions of field-grown Romaine lettuce as an aqueous suspension displays a rapid decline in numbers of culturable cells that is independent of geographic region and local environmental conditions.

    " Field trials confirm that, in Romaine lettuce and its growth soil, changes in the ratio of typical to atypical coliform bacteria are of little value in estimating time elapsed post-pollution event; whereas, because certain phylogenetic groups of E. coli appear to be more adept at survival outside the gastrointestinal tract, variation in the relative proportion of each group may prove useful in this regard, plus provide an indication as to possible source of pollution.

    " E. coli O157:H7 that persists in a culturable form, without significant changes in its numbers, for upwards to 18 days on stored baby spinach is capable of moving to and colonizing (cross-contaminate) new leaves for all of this period.

    " Better understanding of factors that may impose risk of contamination of lettuce for whole and fresh-cut market " " Two prospective fungicides providing excellent control of sour rot, Rhizopus rot, gray mold and black molds can be applied as a recoverable drench or immersion bath which would include a sanitizer that would keep the treatment site as well as downstream packing line equipment sanitary.

    " The demonstrated ability of Salmonella to survive on lemon and lime slices, and transfer into beverages, suggests a potential food safety risk associated with improperly handled sliced citrus.

    " Natural light labeling tomatoes does not adversely affect the tomato surface with respect to pathogen survival, even in the presence of soft-rot pathogens and offers industry a permanent, safe alternative to traditional adhesive labeling.

    " Natural-light labeling citrus fruit peels and subsequent waxing in any order does not allow for the growth nor influence the natural decline of Salmonella populations on citrus fruit surfaces as compared to controls.

    " Plant and soil microflora as well as the method of contamination can play a role in inhibiting the growth of E. coli O157:H7, Listeria monocytogenes, Salmonella spp., and Staphylococcus aureus. Plant injury increased the persistence of E. coli O157:H7 and Salmonella.

    " E. coli was found to persist in soil up to 196 days after application of contaminated irrigation water; Salmonella enterica persisted up to 231 days in soil amended with contaminated compost. No internal or external contamination of E. coli O157:H7 was found on leafy green leaves; but some internalization to the roots occurred in as little as 7 days after contamination. This would appear to indicate that E. coli contamination was not transported within plant tissues. Salmonella was detected on lettuce and parsley surfaces for up to 63 and 231 days respectively after soil contamination, possibly from rain or irrigation water splashes. Lettuce and spinach seed grown in contaminated soil did not display any internalization of E. coli cells. No internalization was found in greens regrown after cutback.

    " On inoculated, pre-harvest lettuce plants, significantly fewer E. coli cells on Day 14 were found inside insect-affected leaves than the control leaves, possibly due to stimulation of plant defences.

    " Storage at higher temperatures (8-12C) appeared to stimulate E. coli O157:H7 growth on damaged leaves of spinach, cilantro and parsley, but not baby Romaine lettuce. This lack of growth could be associated with tissue oxidation or the presence of antioxidants. Leaf extracts do not provide a good model for simulating behavior of E. coli O157:H7 associated with damaged leaves.

    " Salmonella grew rapidly on chopped vegetables in salsa stored at 12 or 21C, except formulations that contained both fresh garlic and lime juice. No growth was seen on salsa held at 4C.

    " Human noroviruses and Hepatitis A can easily contaminate other produce, kitchen utensils and surfaces if adequate brushing or peeling, and washing of fresh produce are not followed.

    " In-field washing techniques used by small farmers to remove dirt are not sufficient to remove Salmonella and norovirus pathogens from leafy greens. A 2 log reduction of both pathogens on spinach was observed after treatment in chlorinated water. Further studies are needed to determine whether consumers do not rinse produce as long when they believe it to be dirt free.

    " Liquid and foam sanitizers containing 5% levulinic acid were effective against murine norovirus (MNV), a surrogate for human norovirus. The rate of transfer of norovirus to small hand-picked fruit indicate a high survival rate of pathogen, if hygiene procedures are not followed by harvesters or the fruit is not properly washed before consuming.

    " Washing fresh lettuce and tomatoes in SAEO water for 15 seconds reduced inoculated E. coli O157:H7 cell numbers by 6.6 to 7.6 log.

    " Juice from noni (Morinda citrifolia L.), a tropical plant widely grown in the Pacific islands, holds promise as a natural preservative. However, food constituents might affect its antimicrobial activity.

    " Surface morphology and topology, among other surface characteristics, effect adhesion and removal of pathogenic organisms to and from produce surfaces. Investigations to optimize the flow conditions (velocity/shear, agitation, flow pattern) to maximize the efficacy of a washing operation are being conducted. Research effort is also placed on how to combine several intervention technologies to achieve a target inactivation of bacteria without compromising the quality of produce.

    Impact Statements:
    1. S-294 scientists working in food safety have provided the fresh and fresh-cut fruit and vegetable industries with critical information to resolve ongoing food safety issues which challenge existence of the industry
    2. S-294 scientists have presented courses to the industry promoting practices and technologies to ensure product quality and safety. These include: the Better Process Control School, a school authorized by the U.S. Food and Drug Administration , Juice Processing Workshop, Tomato Processing School, and the Advanced Processing Technologies Course.
    3. S-294 scientists have identified sources of human pathogen contamination and means for their mitigation in leafy vegetable crops.
    4. S-294 scientists have developed a hand-held device to survey food processing areas for detection of bacterial and bioagent contamination on food surfaces, which is now being applied by the industry.
    5. The S-294 working group has been involved in the discussions with the Research Division of the UFPA. Research priorities and how to develop better interactions between researchers and industry are being discussed.
    6. The S-294 members presented 16 posters and 4 oral presentations at the United Fresh2011 trade show. These posters and presentations generated interest from industry and led to follow-up interactions with researchers
    7. A food security audit program developed by members of S-294 is being used by fresh produce growers and processors including fresh-cut processors to reduce risk of contamination
    Last Modified: 15-Jul-2011
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