Progress 09/01/10 to 08/31/15
Outputs
Target Audience:Fresh and fresh-cut produce processors, packers, retailers; Food service QA manager; Food scientists; Food display equipment manufacturers; Food safety managers, FDA Consumer Officer; and CDC researchers. In addition, project team provided trainings and laboratory experience to students of diverse ethnicity, including Hispanic and African-American student. We provided on-onsite visit to Hispanic Serving Institution (HSI) program directors and mentored HSI and African-American students. Changes/Problems:
Nothing Reported
What opportunities for training and professional development has the project provided?Training/professional development was provided to eight undergraduate and three graduate students from University Maryland, and one graduate student each at Johns Hopkins University, MIT, UIUC, and University of Arizona. Also trained five postdoctoral associates and four visiting professors at USDA-ARS, and one postdoctoral associate each at Johns Hopkins University and MIT. Graduate students and postdoctoral associates attended professional meetings, symposia, and workshops organized by the Institute of Food Technologists, International Association for Food Protection, and the National Institute for Mathematical and Biological Synthesis, and Center for Produce Safety. Project also provided training opportunities to minority students and those from Hispanic Serving Institute, and Historically Black College. How have the results been disseminated to communities of interest?A multitude of mechanisms has been used to communicate the findings to stakeholders in industry, academia, and policy making bodies. These include publications in peer-reviewed journals and trade publications, presentations at scientific and industry meetings, face-to-face meetings and social media outreach, on-site visits to stakeholders and hosts of stakeholder visits to our research facilities, and working side-by-side in research and doing demonstrations at stakeholders' pilot plant and commercial processing facilities. Outreach activities were carried out by researchers and extension specialists located in major specialty crop production and processing areas. Organized and hosted two food safety conferences and stakeholder visits at Beltsville, Md., in conjunction with the produce industry public policy conferences held in Washington, D.C. Over 80 people, including technical executives from industry, FDA policy specialists, researchers, students, and industry journalists, attended these meetings. All project team members presented research findings and explained, in nontechnical language, how to translate these findings into action steps. Informed stakeholder advisory board members about our new findings and sought their input during two face-to-face meetings, several video conference calls, and many email exchanges. The PD served on the produce industry association's food safety and technology council and shared research findings with the industry technical executives during the council meetings (often attended by more than 50 companies) held twice a year. Co-organized, in collaboration with the NSF-supported National Institute for Mathematical and Biological Synthesis, the first international workshop on "Modeling Microbial Contamination of Fresh Produce". Fully utilized Internet video outreach and social media interfacing to disseminate information to stakeholders. The University of Arizona team developed and maintained a website (https://www.cals.arizona.edu/fps/node/58) that updated project activities and research publications. We also used Facebook, Twitter, and Pinterest for outreach activities. Since the live release in 2013, these sites have generated over 11,170 global interactions in fresh produce safety, and continue to grow daily. Created and published a YouTube channel with a collection of 4 targeted training and demonstration modules, providing project impacts directly to users. Total viewership exceeded 500 from nine countries within the two months after its launch. Video modules can be viewed on the Fresh Produce Safety Channel (http://www.youtube.com/user/FreshProduceSafety/featured). Also held five webinars with produce industry and government regulatory personnel, reaching more than 40 companies in the produce processing and retailing industries. What do you plan to do during the next reporting period to accomplish the goals?
Nothing Reported
Impacts
What was accomplished under these goals?
IMPACT Our research has provided FDA, leafy green processors, and food retailers the scientific basis for landmark changes in standards and operations to prevent pathogen cross-contamination, spread, and proliferation during fresh-cut produce washing and retail display. Our groundbreaking research is used by FDA and industry to reset food safety standards. We are the first to show that the industry-standard "Control Limit" chlorine concentration does not prevent pathogen cross-contamination, and that re-washing of contaminated product is an ineffective "Corrective Action" to rectify process failures. This seminal work overturned historical industry practices by documenting the risks associated with operating practices previously considered safe. We also determined the necessary and sufficient sanitizer concentration to prevent pathogen cross-contamination and spread. These results are now incorporated into an interagency and industry task force document supporting Food Safety Modernization Act implementation. Canadian researchers have used our findings to develop mathematical models to predict contamination, and the US Department of Homeland Security has incorporated our results into anti-terrorism programs. Established the scientific basis for fundamentally new approaches to improve process controls for organic load and sanitizers in produce washing. By delineating interactions between free-chlorine concentration, organic load, chlorine demand, produce quality, and safety, we, in partnership with fresh-cut processors, demonstrated the direct effect of chlorine concentration on pathogen cross-contamination, and deleterious effects of organic load on free-chlorine levels and pathogen survival. These findings identified key factors in bacterial inactivation during commercial washing, which helped industry set priorities, enabled development of science-based food safety practices, operational standards, and process controls,. Moreover, these results have stimulated development of innovative, processing equipment designs to reduce organic loads and improve wash-water quality. Invented four novel technologies to overcome roadblocks in fresh produce wash research and operations: 1) a novel microfluidic mixer to determine sub-second time-dose responses for bacterial inactivation by anti-microbial agents. Currently in use by the CDC and University of Maryland, this patent-pending technology filled an instrumentation void, allowing researchers to accurately determine anti-bacterial kinetics; 2) a novel in-flight washer which removes organic exudate from fresh-cut produce immediately after cutting, reducing loss of sanitizer strength, and water and chemical consumption; 3) a chlorine-dosing program enabled the development and transformation of chlorine control from currently feedback to feed forward, and eliminate trial-and-error practices; and 4) biomimetic plant surfaces to facilitate reproducible experiments involving microbial disinfection and attachment/release from plant surfaces, and eliminating leaf-to-leaf variability in experiments with real produce. Identified a cost-effective mechanism to improve cold chain integrity and fully implement food safety preventive controls during retail display. Open refrigerated display cases typically have significant temperature nonuniformity, presenting technical challenges for maintaining temperature below 5 °C at the front, without freezing damage at the rear. Our research found that retrofitting open cases with doors achieved Food Code compliance, with nearly-uniform product temperatures below 5 °C throughout the case. These conditions prevented growth of all major human pathogens and improved product quality and shelf life. Moreover, energy costs were 69% less than for open cases, allowing retrofit cost recovery in less than two years. Reduced costs for product rotation and savings from reduced spoilage are also expected. We informed retailers of these results via meetings, webinars, publications, and personal contact; use of doors on fresh-cut produce retail cases has substantially increased in the last two years. OUTPUT Obj. 1 Optimize fresh-cut produce wash system configurations and operations. 1) Investigated pathogen survival/inactivation dynamics during chlorine depletion/replenishment, demonstrating that no pathogens survive when free-chlorine is maintained above a critical level, irrespective of organic loading; 2) Quantified effects of flow on shearing off of pathogen colonies from spinach surfaces (in collaboration with Massachusetts Institute of Technology); 3) Identified major organic components that deplete free chlorine in wash water, thus providing specific targets for removal in treatment of spent process water for reuse (in collaboration with Johns Hopkins Univ.); 4) Invented four novel technologies to overcome mechanistic roadblocks in fresh produce wash research and operations; 5) Demonstrated that incorporating a washing step prior to cutting significantly improves pathogen inactivation and prevention of cross-contamination. Obj. 2 Develop innovative approaches, processes, and hardware to wash leafy greens. The Univ. of Illinois Urbana-Champaign (UIUC) team tested combinations of sonication, sanitizers, and surfactants on pathogen reduction and produce quality. This work significantly advanced understanding of ultrasonic pathogen inactivation, and optimized process parameters to improve inactivation while maintaining quality. Separately, the UIUC team further verified that washing-before-cutting provides significant benefit in reducing microbial counts and improving sanitizer efficacy. Obj. 3 Develop/test technology to improve cold-chain integrity and compliance with FDA temperature control regulations for produce safety. We addressed the large temperature variations of bagged salad displayed in open refrigerated display cases, in the front often above the FDA Food Code's 5 °C limit. We evaluated many options, including optimizing operating parameters, using insulators and phase change materials, installing curtains, and retrofitting open cases with clear glass doors. For typical display cases, we mapped temperature distributions, and conducted quality and safety studies. After selecting retrofitting with glass doors, we conducted large validation trials with several leafy greens, to assess freshness, visual quality, human pathogen growth, and energy consumption. We showed that installing clear doors achieved nearly uniform product temperature (0.6 to 4.2 °C) and Food Code compliance, and prevented pathogen growth. Product quality and shelf-life improved, and 69% less energy was consumed for typical door opening frequencies and durations (every 10 min for 6 sec). Obj. 4 Provide outreach and facilitate technology transfer. Detailed in "How have the results been disseminated to communities of interest" section. Obj. 5 Evaluate social, economic, and environmental impacts of implementation of these technologies. Economists (Univ. Arizona and USDA-ERS) interviewed five major fresh-cut processors to analyze costs/benefits of ultrasound in postharvest washing of leafy greens. Key factors affecting adoption were identified and shared with industry and other researchers. Retrofitting doors to display cases in actual retail settings was also analyzed. For an anonymous regional supermarket chain (120 stores), same-store sales before and after retrofitting, and between stores with and without retrofitting, were compared. No negative sales impact of door installation was found. The results should promote retail display of bagged salad behind glass doors, given the benefits for food safety, quality, and energy savings.
Publications
- Type:
Journal Articles
Status:
Published
Year Published:
2015
Citation:
De Fr�as, J.A., Luo, Y., Kou, L., Zhou, B. and Wang, Q. 2015. Improving spinach quality and reducing energy costs by retrofitting retail open refrigerated cases with doors. Postharvest Biology and Technology. 110:114-120.
- Type:
Journal Articles
Status:
Published
Year Published:
2015
Citation:
Lin, B., Luo, Y., Zhang, Z., Zhang, B., Zhou, B., and Wang, Q. 2015. Development of silver/titanium dioxide/chitosan adipate nanocomposite as an antibacterial coating for fruit storage. LWT. Food Science and Technology. 63:1206-1213.
- Type:
Journal Articles
Status:
Published
Year Published:
2015
Citation:
Zhou, B., Luo, Y., Nou, X., Lyu, S., and Wang, Q. 2015. Survival dynamics of Salmonella enterica, Listeria monocytogenes, and Escherichia coli in wash water during simulated chlorine depletion and replenishment processes. Food Microbiology. 50:88-96.
- Type:
Journal Articles
Status:
Published
Year Published:
2015
Citation:
Xiao Z, Bauchan G, Nichols-Russell L, Luo Y, Wang Q, Nou X. 2015. Proliferation of Escherichia coli O157:H7 in soil and hydroponic microgreen production systems. Journal of Food Protection. 78:1785-1790.
- Type:
Other
Status:
Published
Year Published:
2015
Citation:
De Fr�as, J.A., Luo, Y., Zhou, B., Millner, P., and Nou, X. 2015. Lower temperatures, in cases with doors, improve produce quality and safety with reduced energy consumption. Produce Business Magazine. 31:14.
- Type:
Journal Articles
Status:
Published
Year Published:
2015
Citation:
Yan, S., Luo, Y., and Yang, T. 2015. The mechanism of ethanol treatment on inhibiting lettuce enzymatic browning and microbial growth. LWT - Food Science and Technology. 63:383-390.
- Type:
Journal Articles
Status:
Awaiting Publication
Year Published:
2016
Citation:
Weng, S.C., Luo, Y., Li, J., Zhou, B., Jacangelo, J., and Schwab, K.J. 2016. Vegetable wash water chemical characterization and chlorination. Food Control. 60:543-551.
- Type:
Journal Articles
Status:
Published
Year Published:
2015
Citation:
Zhang, B., Luo, Y., Zhou, B., Wang, Q., and Millner, P.D. 2015. A novel microfluidic mixer-based approach for determining inactivation kinetics of Escherichia coli O157:H7 in free chlorine solutions. Food Microbiology. 49: 152-160.
- Type:
Journal Articles
Status:
Published
Year Published:
2015
Citation:
Huang, J., Luo, Y., and Nou, X. 2015. Growth of Salmonella enterica and Listeria Monocytogenes on fresh-cut cantaloupe under different temperature abuse scenarios. Journal of Food Protection. 78:1125-1131.
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2014
Citation:
Wilson, R., Bevington, R., Nolte, K.D., and Ravishankar, S. 2014. Extending Research Impacts to a General Audience Via Video: The Good, The Bad, And The Ugly. Abstract published in the proceedings at the 2014 American Society for Horticultural Science Annual Meeting, Orlando, FL.
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2014
Citation:
Bevington, R., Nolte, K.D. and Ravishankar, R. 2014. Best Methods to Present Research Information via Video Formats to a Public Audience. Abstract published in the proceedings at the 2014 American Society for Horticultural Science Annual Meeting, Orlando, FL.
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2013
Citation:
Bevington, R., Ravishankar, S. and Nolte, K.D. 2013. How To: Making an Informative Video from Start to Finish. Abstract published in the proceedings at the 2013 American Society for Horticultural Science Annual Meeting, Palm Desert, CA.
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2015
Citation:
Zhang, B., Luo, Y., Pearlstein, A., Bauchan, G., Nou, X., Wang Q., Millner, P. 2015. Fabrication of Biomimetically Patterned Surfaces and Their Application to Probing Plant?Bacteria Interactions at the 2015 Institute of Food Technologists Annual Meeting, Chicago, IL, July 2015.
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2015
Citation:
Zhang, B., Luo, Y., Millner, P. 2015. A Novel Microfluidic Mixer-Based Approach for Determining Subsecond Inactivation Kinetics of Escherichia Coli O157:H7 to Prevent Cross-Contamination at the 2015 Institute of Food Technologists Annual Meeting, Chicago, IL, July 2015.
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2015
Citation:
De Frias, A., Luo, Y., Kou, L., Zhou, B. 2015. Retrofitting Open Refrigerated Display Cases with Doors for Packaged Greens: Greater Compliance with FDA Food Code and Improved Food Quality at the 2015 Institute of Food Technologists Annual Meeting, Chicago, IL, July 2015.
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2015
Citation:
Zhou, B., Luo, Y., De Frias, A., Nou, X., Millner, P., Wang, Q. 2015. Fate of human pathogens in packaged leafy greens stored in a refrigerated display cabinet with doors at the 2015 Institute of Food Technologists Annual Meeting, Chicago, IL, July 2015.
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2015
Citation:
De Frias, A., Luo, Y. 2015 Modification of retail open refrigerated display cabinets result in significant energy savings, compliance with Food Code, and improved food quality and safety at the 2015 Institute of Food Technologists Annual Meeting, Chicago, IL, July 2015.
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2015
Citation:
De Frias, A., Luo, Y., Zhou, B., Nou, X., Millner P., Wang, Q. A simple and cost-effective solution to maintain fresh-cut produce quality and safety during retail display at the 2015 Institute of Food Technologists Annual Meeting, Chicago, IL, July 2015.
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2015
Citation:
Zhang, B., Luo, Y., Millner, P. Biomimetically patterned surface & validation of sanitization condition at 1890-Institutions Food Safety Conference, Beltsville, MD. April 2015.
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2015
Citation:
De Frias, A., Luo, Y., Kou, L., Zhou, B., Wang, Q. Modification of retail open refrigerated display cabinets result in significant energy savings, compliance with Food Code, and improved food quality at the 1890-Institutions Food Safety Conference. April 2015.
|
Progress 09/01/13 to 08/31/14
Outputs
Target Audience: Fresh and fresh-cut produce processors, packers, retailers; Food scientists; Food display equipment manufacturers; Food safety managers, decision makers, and regulators. Changes/Problems:
Nothing Reported
What opportunities for training and professional development has the project provided? Training/professional development was provided to five undergraduate and three graduate students from University of Maryland, and one graduate student each at Johns Hopkins University and University of Arizona. Also trained three postdoctoral associates and four visiting professors at USDA-ARS, and one postdoctoral associate at Johns Hopkins University. Graduate students and postdoctoral associates attended professional meetings, symposia, and workshops organized by the Institute of Food Technologists, International Association for Food Protection, and the National Institute for Mathematical and Biological Synthesis. How have the results been disseminated to communities of interest? Research findings have been disseminated to our stakeholders via peer-reviewed publications, workshops, symposia, webinars, and direct correspondence (in person, emails, phone calls, and video conferences). We provided updates to FDA, USDA, CDC, Food Marketing Institute, Produce Marketing Association, United Fresh Produce Association, Ecolab, Taylor Farms, Ready Pac, Dole Fresh Vegetables, Chiquita Brands Intl., NewStar Fresh Foods, Earthbound Farms, and Hussmann Corp. We hosted a Food Safety Conference and Tour of our research facilities at USDA-ARS-Beltsville Agricultural Research Center. Technical executives (>20) from the produce industry and policy makers from FDA (>10) attended and toured the research facilities used in this project. In addition, we shared the important findings from the cold chain study, via webinar, with national representatives of the produce and retail industries and FDA. What do you plan to do during the next reporting period to accomplish the goals? We will fine tune the technical aspects of the project and focus on economic analyses and outreach/extension initiatives as follows: Test the effects of organic load on pathogen inactivation kinetics using the micro-fluidic device. Test pathogen inactivation kinetics with a broad range of bacterial strains and biocides. Develop technology to remove organic load and decrease chlorine demand from produce wash water. Perform full-scale economic analysis (energy consumption, food safety, food quality, shelf life, product rotation, and capital expenditures) at research and retail levels for open refrigerated display cabinets and display cabinets with doors. Perform temperature distribution assessments and food quality/safety evaluations for a novel open refrigerated display cabinet with improved isolation from ambient air. Offer additional webinars/workshops to the industry stakeholders, publish articles in fresh-cut trade journals. Complete project website development with frequently updated research information.
Impacts
What was accomplished under these goals?
IMPACT: Invented and utilized a novel device to provide critical pathogen inactivation data unobtainable by conventional methods. The device is currently used by the Center for Disease Control and Prevention (CDC). Additional research clarified misconceptions about sanitizer concentrations for pathogen control in produce wash conditions, an essential contribution towards establishing science-based critical control limits. These accomplishments significantly advance the multi-agency "White Paper" that supports the implementation of the Food Safety Modernization Act (FSMA) in the areas of sanitation validation and preventive control. Identified and proved the viability of a solution to the long-standing challenge of ensuring the FDA Food Code on temperature control for food safety at retail. This solution significantly reduces operational energy costs, improves product quality and prevents pathogen growth; thereby benefiting fresh-cut processors, retailers, and consumers. These new findings also provide insights towards future National Standards for sanitary design and performance of commercial refrigerated display cases. Output Objective 1: Invented, fabricated, and tested a novel micro-fluidic mixer to accurately determine time-dose responses of pathogen inactivation with chlorine solutions from 0.1 second to 5 minutes. This invention provides a valuable tool for researchers to determine pathogen inactivation kinetics in the sub-second time scale. A patent was filed. Additionally, we developed biomimetic plant surfaces to enable reproducible experiments involving disinfection and attachment/release of microbes from plant surfaces, without any of the leaf-to-leaf or plant-to-plant variability that confounds experiments with real produce. Investigated pathogen survival/inactivation dynamics during chlorine depletion/replenishment processes with initial chlorine and organic loads during produce wash operations. Demonstrated that no pathogens survived when free-chlorine levels in wash-water were maintained above a critical concentration, irrespective of initial free-chlorine levels or organic loads. In collaboration with Johns Hopkins University, we further investigated chlorine-chemical interactions in produce wash water to identify and develop strategies/technologies to reduce organic loads. Objective 3: We optimized equipment design and operational parameters for refrigerated display cabinets to maintain FDA's Food Code temperature requirement for packaged fresh-cut leafy greens at ≤5 °C, previously challenged by significant temperature differentials (often ≥7 °C) commonly encountered in open retail refrigerated display cabinets. Working with equipment manufacturers and the food industry, we tested many options and in three large trials we validated the quality and safety of packaged fresh-cut leafy greens during cold display in cabinets retrofitted with clear glass doors, which reduced temperature variations and achieved compliance with the FDA Food Code without freezing products. A display cabinet with doors prevented the growth of E. coli O157:H7, Salmonella enterica, and Listeria monocytogenes over a commonly used display period of 3-4 days, as temperatures remained nearly uniform, between 0.6 °C and 4.2 °C. In addition, operational energy costs were 69% less than open-display cabinets, and door retrofit costs can be recouped in less than two years by energy savings alone. Reduced labor costs from reduced product rotations are expected along with savings from reduced product spoilage. Objective 4: Our team of economists investigated the potential costs and benefits of adopting ultrasound as part of the post-harvest washing process for leafy greens, including iceberg lettuce, romaine lettuce, and spinach. In-depth interviews were conducted with key personnel at three leafy-green processors, including Dole Fresh Vegetables, New Star, and Taylor Farms. Key factors affecting adoption of this technology were discussed, including pathogen inactivation efficacy, residence time, design and installation of retrofits to existing lines, electricity use, maintenance and replacement costs for transducers, cost of cleaning exposed surfaces of ultrasound devices, and potential worker safety issues resulting from exposure to ultrasound. In a different study, we are investigating the costs and benefits of retrofitting doors to open-display retail refrigerated cabinets both at the research level and in actual retail settings.
Publications
- Type:
Journal Articles
Status:
Published
Year Published:
2014
Citation:
Kou, L., Luo, Y., Ingram, D.T., Yan, S., Jurick, W.M. 2015. Open-refrigerated retail display case temperature profile and its impact on product quality and microbiota of stored baby spinach. Food Control. 47: 686-692.
- Type:
Journal Articles
Status:
Published
Year Published:
2014
Citation:
Kou, L., Luo, Y., Park, E., Turner, E.R., Barczak, A, Jurick, W.M. 2014. Temperature abuse timing affects the rate of quality deterioration of commercially packaged ready-to-eat baby spinach. Part I: Sensory analysis and selected quality attributes. Postharvest Biology and Technology. 91: 96-103.
- Type:
Journal Articles
Status:
Published
Year Published:
2014
Citation:
Palma-Salgado, S., Pearlstein, A.J., Luo, Y., Park, H.K., Feng, H. 2014. Whole-head washing, prior to cutting, provides sanitization advantages for fresh-cut Iceberg lettuce (Latuca sativa L.). International Journal of Food Microbiology. 179: 18-23.
- Type:
Journal Articles
Status:
Published
Year Published:
2014
Citation:
Zhang, B., Luo, Y., Pearlstein, A.J., Aplin, J., Liu, Y., Bauchan, G.R., Payne, G.F., Wang, Q., Nou, X., Millner, P.D. 2014. Fabrication of biomimetically patterned surfaces and their application to probing plant-bacteria interactions. ACS Applied Materials and Interfaces. 6(15): 12467-12478.
- Type:
Journal Articles
Status:
Published
Year Published:
2014
Citation:
Zhou, B., Luo, Y. Nou, X., Millner, P. 2014. Development of an algorithm for feed-forward chlorine dosing of lettuce wash operations and correlation of chlorine profile with Escherichia coli O157:H7 inactivation. Journal of Food Protection. 77(4):558-566.
- Type:
Journal Articles
Status:
Published
Year Published:
2014
Citation:
Xiao, Z., Nou, X., Luo, Y., Wang, Q. 2014. Comparison of the growth of Escherichia coli O157: H7 and O104: H4 during sprouting and microgreen production from contaminated radish seeds. Food Microbiology. 44: 60-63.
- Type:
Journal Articles
Status:
Published
Year Published:
2014
Citation:
Xiao, Z., Lester, G. E., Luo, Y., Xie, Z., Yu, L., Wang, Q. 2014. Effect of light exposure on sensorial quality, concentrations of bioactive compounds and antioxidant capacity of radish microgreens during low temperature storage. Food Chemistry. 151: 472-479.
- Type:
Journal Articles
Status:
Published
Year Published:
2014
Citation:
Xiao, Z., Luo, Y., Lester, G., Kou, L., Yang, T., Wang, Q. 2014. Postharvest quality and shelf life of radish microgreens as impacted by storage temperature, packaging film, and chlorine wash treatment. LWT-Food Science and Technology. 55(2): 551-558.
- Type:
Journal Articles
Status:
Published
Year Published:
2014
Citation:
Zhou, B., Luo, Y., Nou, X., Yang, Y., Wu, Y., Wang, Q. 2014. Effects of postharvest handling conditions on internalization and growth of Salmonella enterica in tomatoes. Journal of Food Protection. 77(3): 365-370.
- Type:
Journal Articles
Status:
Published
Year Published:
2014
Citation:
Zhou, B., Luo, Y., Turner, E.R., Wang, Q., Schneider, K.R. 2014. Evaluation of current industry practices for maintaining tomato dump tank water quality during packinghouse operations. Journal of Food Processing and Preservation. 38(6): 2201-2208.
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2014
Citation:
Zhou, B., Luo, Y., Schmidt, W., Broadhurst, L., Millner, P., Vanotti, M., Li, J. 2014. Analysis of chlorine replenishment process of lettuce washing water and the evaluation of several strategies for improving water quality. International Association for Food Protection Annual Meeting, Indianapolis, IN, August 2014.
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2014
Citation:
Zhou, B., Luo, Y., Nou, X., Lyu, S. 2014. Fate of Listeria monocytogenes in lettuce wash water during chlorine replenishment. International Association for Food Protection Annual Meeting, Indianapolis, IN, August 2014.
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2014
Citation:
Luo, Y., Yan, S. A novel treatment combination for the dual control of enzymatic browning and pathogen growth on apple slices. T1. International Union of Food Science and Technology - 17th World Congress of Food Science and Technology and Expo. Montreal, Canada, August 2014.
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2014
Citation:
Xiao, Z., Park, E., Lester, G. E., Saftner, R., Luo, Y., Wang, Q. 2014. Evaluation of sensory attributes, chemical compositions, and phytonutrient concentrations of microgreens. Abstract, Institute of Food Technologists Annual Meeting, New Orleans, LA, June 2014.
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2014
Citation:
Zhang, B., Luo, Y., Wang, Q., Nou, X., Millner, P. 2014. Fabrication and potential application of biomimetic surface for probing plant-bacteria interactions. International Association for Food Protection Annual Meeting, Indianapolis, IN, August 2014.
- Type:
Conference Papers and Presentations
Status:
Other
Year Published:
2014
Citation:
De Frias, J. A., Kou, L., Ingram, D., and Luo, Y. 2014. Modification of retail open refrigerated display cabinets result in significant energy savings, compliance with Food Code, and improved product quality. Invited presentation at the Food and Drug Administration. College Park, MD.
|
Progress 09/01/12 to 08/31/13
Outputs
Target Audience: Fresh and fresh-cut produce processors, packers, retailers; Food scientists; Food display equipment manufacturers; Food safety managers, decision makers, and regulators. Changes/Problems:
Nothing Reported
What opportunities for training and professional development has the project provided? This project has provided training and professional development to five undergraduate students and three graduate students at University of Maryland; three postdoctoral research associates and four visiting professors at USDA-ARS, and two postdoctoral research associates at University of Illinois at Urbana-Champaign. In addition, the project sponsored the graduate students and postdoctoral research associates’ attendance at professional meetings and at the symposium organized by the Institute of Food Technologists, International Association for Food Protection, and the Center for Produce Safety. How have the results been disseminated to communities of interest? Research findings generated have been disseminated to the stakeholders via peer-reviewed publications, workshops, symposium presentations, and direct correspondences (in person, emails, phone calls, and video conferences). Project team members also visited Dole Fresh Vegetables, Wegmans Food Markets, and Hussmann, and hosted on-site visits for personnel at 3M, Sensitech, Hussmann, BASF, and the FDA to discuss research findings. Results were also shared with the produce industry at their food safety symposium. What do you plan to do during the next reporting period to accomplish the goals? Work with the produce industry to further develop and test the algorithm for feed-forward control of chlorine dosing to maintain target levels of chlorine concentration during produce wash. Investigate the effect of produce surface topographic features, and chemical and biochemical properties on pathogen attachment and inactivation using both real plant tissues and biomimetic surfaces. Develop technologies to reduce chlorine demand in the wash solution and improve sanitizer efficacy on pathogen inactivation. Further develop new technologies with enhanced pathogen inactivation while maintaining product quality using a combination of ultrasound, surfactants, and sanitizers. Work further with industry to evaluate and document how doors, night curtains, and phase change materials affect performance of retail display cabinets for fresh-cut produce, with emphasis on temperature uniformity, product quality and safety, energy consumption, and consumer acceptance. Perform detailed analysis of capital and operating costs associated with incorporating our suggested changes to produce wash systems, and the addition of doors or night curtains to retail product display cabinets. Implement extensive educational programs via meetings, extension publications, and workshops, etc., and develop a website featuring project objectives, and findings to facilitate dissemination of information and adoption of technology.
Impacts
What was accomplished under these goals?
IMPACT: Major progresses have been made in addressing the critical stakeholder needs for improving food safety in the following two areas: 1) Inactivation of pathogens and prevention of cross-contamination through optimization of produce wash system design and operation, and development of innovative washing processes and technologies; and 2) Prevention of pathogen proliferation at what is currently the weakest link in the cold chain, namely retail store produce cold display. In reducing pathogen contamination, we determined major operating parameters to enhance sanitizer efficacy on pathogen inactivation, and developed and validated a novel algorithm for accurately determining sodium hypochlorite inputs needed to maintain target levels of free chlorine concentration required for pathogen control. Our research efforts have significantly expanded the knowledge base regarding wash operating conditions affecting sanitizer degradation and the consequences on pathogen survival and spread. Our publications have been used by researchersat York University (Canada) to develop mathematical models to predict contamination. Our published and unpublished data are being used by the U.S. Department of Homeland Security as a resource for the development of anti-terrorism programs, and by FDA officials and industry technical executives to develop a white paper addressing cross-contamination issues during produce wash operations. Our study on the fresh-cut produce operations of Iceberg lettuce clearly demonstrated the advantage of washing whole-head Iceberg lettuce before cutting in significantly enhancing reductions in E. coli O157:H7, compared to traditional washing after cutting sequence. This procedure reduces depletion of sanitizer, reduces bacterial attachment sites at the cut/wounded tissue surfaces, and reduces transfer of microbial contamination from exterior to interior leaves via the cutting blades. In reducing pathogen proliferation in supply chain, we identified the major technical issues with current commercial display cabinets that impede compliance with the FDA Food Code temperature requirements for “Temperature Control for Safety Foods” (41 °F =5 °C). We further demonstrated that installation of doors and night curtains and/or using novel phase change materials can significantly improve the uniformity of the case temperature. This demonstration of the food safety and quality benefits of cabinets with doors paves the way for the commercialization and adoption of this technology, which also has the potential for significant reduction in energy consumption. The demonstration that phase-change materials can reduce temperature spikes during the needed equipment defrost periods establishes a pathway stimulating technological innovations to ensure proper cold-chain temperatures for produce during retail display. To improve cabinet designs, information pertaining to temperature control has been shared with BASF Corp., Entropy Solutions Inc., and Hussmann Corp., via webinars and onsite visits. Output: Objective 1: The USDA-ARS project team investigated the dynamic relationships involved in fresh-cut produce wash operations (water quality factors, sanitizer efficacy, and produce quality and safety) and determined which major operating parameters enhance sanitizer efficacy on pathogen inactivation. We developed and validated a novel algorithm for accurately determining sodium hypochlorite inputs needed to maintain target levels of free chlorine concentration required for pathogen control under different wash system configurations and operating conditions. We also developed a soft-lithography fabrication method to manufacture biomimetic food surfaces to make synthetic (polydimethylsiloxane and agarose) models that have surface microstructure and topographic features representative of spinach leaf and netted melon rind (cantaloupe) surfaces. A key advantage of this approach is that it facilitates reproducibility of experiments involving disinfection and attachment/release of microbes from surfaces with microstructure identical to real produce surfaces, but without any of the leaf-to-leaf or plant-to-plant variability that confounds experiments with real produce. Objective 2: The project team from University of Illinois at Urbana-Champaign tested the effect of combining sonication, sanitizers, and surfactant treatments on pathogen reduction the quality of fresh-cut Iceberg and Romaine lettuce, and identified a produce sanitization treatment that enhances pathogen inactivation efficacy while maintaining product quality. Ultrasound power density was optimized to reduce tissue damage and eliminate significant differences in quality among the combined treatments. In addition, the team showed that E. coli O157:H7 populations were significantly reduced when Iceberg lettuce was washed-before-cutting as previously proposed by the USDA-ARS team (instead of typical cut-before-washing). Additional studies using whole, cut, and shredded carrots showed that the lower the surface-area-to-mass (SAM) ratio (whole carrots) was correlated with preservation of the available chlorine and peroxyacetic acid sanitizer concentrations and consequently effective reduction in E. coli O157:H7 populations, whereas with greater SAM ratio (shredded), less sanitizer remained available and the less reduction in E. coli populations. Objective 3: The USDA-ARS project team identified technical issues associated with commonly used retail store produce display cabinets that hinder continuous compliance with FDA Food Code temperature controls for food safety: 1) temperature spikes during equipment defrost cycles; and 2) wide temperature variation within the display cabinets. In collaboration with Hussmann Corp. and Dole Fresh Vegetables, Inc., we established that significant heat intrusion from the ambient surroundings into the open refrigerated display cabinets is the primary technical hurdle preventing compliance with the FDA cold-chain temperature limit of 5°C. Improvements in temperature uniformity were achieved by adding doors or night curtains to new display cabinet designs, and by retrofitting doors to existing units. In addition, we tested a novel concept of using phase change materials to maintain temperature uniformity and reduce temperature fluctuation during defrost cycles. Objective 4: Research findings generated from objectives 1-3 have been disseminated to the stakeholders via peer-reviewed publications, workshops, symposium presentations, and direct correspondences (in person, emails, and phone calls). We also visited the state-of-the-art processing plant of Dole Fresh Vegetables Corp. (Bessemer City, NC), and hosted visits of the industry personnel. In addition, our project team members from University of Arizona and University of California are developing additional training materials and handouts to help stakeholders further utilize the research findings generated from this project. Objective 5: The economists from USDA-ERS and University of Arizona are collecting baseline information regarding the capital and operational cost of produce wash processand cold display at the retail stores. Information gathered will be used to perform the cost-benefit analysis of adopting our research findings into industry and commercial standards and assess contributions on long-term profitability, sustainability, and marketing of specialty crops.
Publications
- Type:
Journal Articles
Status:
Published
Year Published:
2012
Citation:
Luo, Y., Nou, X., Millner, P., Zhou, B., Shen, C., Yang, Y., Wu, Y., Wang, Q., Feng, H., Shelton, D. 2012. A pilot plant scale evaluation of a new process aid for enhancing chlorine efficacy against pathogen survival and cross-contamination during produce wash. International Journal of Food Microbiology 158:133-139.
- Type:
Journal Articles
Status:
Published
Year Published:
2012
Citation:
Shen, C., Luo, Y., Nou, X., Bauchan, G., Zhou, B., Wang, Q., Millner, P. 2012. Fresh produce washing aid, T-128, enhances inactivation of Salmonella and Pseudomonas biofilms on stainless steel coupons in chlorinated wash solutions. Applied and Environmental Microbiology 78(19): 6789-6798.
- Type:
Journal Articles
Status:
Published
Year Published:
2012
Citation:
Zhou, B., Feng, H., Pearlstein, A. J. 2012. Continuous-flow ultrasonic washing system for fresh produce surface decontamination. Innovative Food Science and Emerging Technologies 16: 427-435.
- Type:
Journal Articles
Status:
Published
Year Published:
2013
Citation:
Shen, C., Luo, Y., Nou, X., Wang, Q., Millner, P. 2013. The effects of free chlorine concentration, organic load, and exposure time on the inactivation of Salmonella, Escherichia coli O157:H7 and non-O157 STEC. J. Food Protection. 76(3): 386393.
- Type:
Journal Articles
Status:
Accepted
Year Published:
2013
Citation:
Zhou, B., Luo, Y., Turner, E., Yang, Y., Schneider, K. 2013. Evaluation of current industry practices for maintaining tomato dump tank water quality during packinghouse operations. Journal of Food Processing and Preservation.
- Type:
Journal Articles
Status:
Accepted
Year Published:
2014
Citation:
Xiao, Z., Luo, Y., Lester, G., Kou, L., Yang, T., Wang, Qin. 2014. Postharvest quality and shelf life of radish microgreens as impacted by storage temperature, packaging film, and chlorine wash treatment. LWT- Food Science and Technology.
- Type:
Journal Articles
Status:
Accepted
Year Published:
2014
Citation:
Zhou, B., Luo, Y., Nou, X., Yang, Y., Wu, Y., Wang, Q., 2014. Effects of Postharvest Handling Conditions on Internalization and Growth of Salmonella enterica in Tomatoes. J. Food Protection. Doi:10.4315/0362-028X.JFP-13-307
- Type:
Books
Status:
Awaiting Publication
Year Published:
2013
Citation:
Luo, Y., Ingram, D., and Karan, K. 2013. Chapter 7, Maintaining food safety during produce wash operation. In: Global Safety of Fresh Produce (J. Hoorfar, ed). Woodhead Publishing, Cambridge, United Kingdom.
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2013
Citation:
Wu, R., Luo, Y. and Wang, Q. 2013. Synthesis and antimicrobial study of nanoporous metal-organic frameworks (MOFs) loading essential oils [Abstract]. Proceeding, Beltsville Agricultural Research Center Poster Day. Beltsville, MD.
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2013
Citation:
Zhang, B., Luo, Y., Millner, P. Nou, X., Wang, Q. 2013. Development of a micro fluidic device incorporating a biomimetic interface to assay plant-microorganism interactions critical to food safety of fresh-cut produce [Abstract]. Proceeding, Beltsville Agricultural Research Center Poster Day, Beltsville, MD. April 2013.
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2013
Citation:
Zhou, B., Luo, Y., Turner, E., Yang, Y., Wang, Q. 2013. Correlation analysis on water quality parameter in dump tank water of tomato packing house [Abstract]. Proceeding, Beltsville Agricultural Research Center Poster Day, Beltsville, MD.
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2013
Citation:
Zhou, B., Luo, Y., Nou, X., Millner, P.D. 2013. Process analysis of chlorine replenishment of lettuce washing water [Abstract]. Proceeding, International Association for Food Protection Annual Meeting, Charlotte, NC.
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2013
Citation:
Feng, H., Zhou, B., Lee, H., Li Y., Park, H., Palma, S., Pearlstein, A. 2013. Microbial inactivation by ultrasound for enhanced food safety. Symposium: Chemical & Non-Medical Biological Effects of Ultrasound [Abstract]. Proceeding, 21st International Congress on Acoustics (ICA 2013), Montreal, Canada.
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2013
Citation:
Kou, L., Luo, Y., Yan, S., Ingram, D. T. 2013. Effect of dynamic temperature storage in retail display case on the quality and microbiota of packaged fresh-cut leafy greens [Abstract]. Proceeding, Institute of Food Technologists Annual Meeting, Chicago, IL.
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2013
Citation:
Salgado, S. P., Pearlstein, A. J., Luo, Y., Feng, H. 2013. Cutting head lettuce prior to washing provides advantages in produce sanitization [Abstract]. Proceeding, Institute of Food Technologists Annual Meeting, Chicago, IL.
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Progress 09/01/11 to 08/31/12
Outputs
OUTPUTS: In objective 1, we addressed two critical issues facing the industry. First, we determined the minimum free chlorine concentration needed to prevent pathogen survival and transference during commercial produce wash. Second, we developed a mathematical model to characterize the dynamic relationships between free chlorine, organic load, chloramines hump, and chlorination breakpoint during simulated produce wash with increasing organic load. We reported that no pathogen survival or transference occurred when the free chlorine in wash water was maintained at 10 ppm or higher concentration. We further examined the dynamic relationship between free chlorine concentration, organic load, and exposure time on the inactivation of 12 pathogen strains of Salmonella, Escherichia coli O157:H7 and Non-O157 STEC. In objective 2, we fully leveraged the team's expertise in the fields of pre- and post-harvest technology and engineering to examine realistic contamination matrices on pathogen reduction. Spinach samples were inoculated in the USDA Beltsville's research field and tested in both USDA and University of Illinois facilities. Sample inoculation mimicked real-life leafy green contamination scenarios with E. coli cells mixed with other possible contamination matrices including soil, compost, and dairy manure. We tested washing treatment combinations of: chlorine; chlorine and ultrasound; and chlorine, ultrasound, and surfactants. The Illinois team further validated the USDA team's prior studies of improving food safety by reversing the traditional cut and wash sequence. The team also modified the wash system to improve submergence of whole-head lettuce during washing. In objective 3, ongoing studies are identifying key parameters needed to design, manufacture, and operate commercial display cases to maintain bagged salad quality and compliance with the FDA Food Code. Hussmann Corp. donated two commercial open-refrigerated produce display cases. The team evaluated the thermodynamics of the cases, the effect of equipment duty cycles, and retail management practices on product temperature, quality, and microbial growth. We reported that the large temperature differential between bags in the front of the case (warmest) and those in the back of the case (coolest) is the major technical issue impeding compliance with the FDA food code pertaining to temperature control. We are working closely with the manufacturer to address this issue. The team organized a Beltsville, Maryland, food safety conference with stakeholders, advisors and team members to disseminate information and get feedback. Approximately 15 industry members of the United Fresh Produce Association were also in attendance. Following presentations of research findings, the attendees discussed the applications of the finding for developing food safety standards, and the next steps and directions of the project. The ARS researchers also provided a tour of the research facility, including their fresh-cut produce pilot plant and a mini supermarket with commercial produce display cases. In addition, project team members also shared information with the stakeholders extension meetings held in California. PARTICIPANTS: Luo, Y. (PD); Millner, P. D.(PI); Nou, X.(PI); Feng, H.(PI); Pearlstein, A. J.(PI); Bin Zhou, Yang Yang, Cangliang Shen, Post-Doctoral Associates; Liping Kou, Shoulei Yan, Visiting Professor; Roc Wu, Zhenlei Xiao, Graduate Students; Yitzy Paul, Undergraduate student, Univ. MD; Hyounjgill Lee, Hee Kyung Park, Post-Doctoral Associate, Sindy Palma, Graduate Student, Department of Food Science and Human Nutrition, UIUC. Partner Organizations: University of Maryland, University of Illinois at Urbana-Champaign; University of California Cooperative Extension; University of Arizona; North Carolina State University; USDA-Economic Research Service; Dr. Roger Billingsley, Mr. Tom Johnson, Dole Fresh Vegetables; Jim Brennan, New Leaf Food Safety Solutions, Inc.; Mr. Gene Rizzo, FTNON; Ms. Oriana Leishman, Dr. Katie Swanson, Ecolab, Inc.; Mr. Rolando Gonzalez, Buhler Inc.; Mr. Edmond O'Reilly, Trustwater; Mr. Jorge Saenz, Hussmann. Collaborators: Ms. Susan Ajeska (New Star Fresh Foods; Dr. Barry Eisenberg, Dr. Davis Gombas, United Fresh Produce Association; Ms. Bonnie Fernandez-Fenaroli, Center for Produce Safety; Dr. Qin Wang, University of Maryland; Dr. James Gorny, FDA; Dr. Bob Whitaker, Produce Marketing Association, and Dr. Yuejan Li, Sichuan Academy of Agricultural Sciences, P.R. China. TARGET AUDIENCES: To effectively disseminate the information to the stakeholders, the team organized a USDA-ARS food safety conference in conjunction with the NIFA project stakeholder advisor and team member meeting. Advisors from FDA, produce industry, and industry associations met with the project team and collaborators. In addition, approximately 15 industry members of the United Fresh Produce Association were also in attendance. The ARS researchers also provided the attendees a well organized tour of the research facility, including field plots, fresh-cut produce wash pilot plant, and a mini supermarket with commercial refrigerated produce display cases. In addition, the team member also shared the research findings with the leafy green industry stakeholders during the extension education meetings. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.
Impacts
Our research activities involving produce wash started a few years ago, and have gained significant momentum over the past two years. The completed work under objectives 1 and 2 has significantly advanced the general knowledge and understanding of a dynamic relationship between fresh-cut produce wash operations, water quality, sanitizer efficacy, and produce quality and safety. Industry is beginning to use this information to modify existing wash systems that will allow sufficient sanitizer and contact time between produce and sanitizing solutions to greatly improve pathogen inactivation. Our studies demonstrated that the chlorine concentration currently prescribed for the "Control Limit" in the industry-wide Hazardous Analysis and Critical Control Point (HACCP) program is insufficient to prevent pathogen survival and cross-contamination. We also showed that re-washing recently cross-contaminated fresh-cut leafy greens is not an effective "Corrective Action" to remediate process failures. We further determined that maintaining free chlorine at 10 ppm or higher concentration in the wash solution is critical to prevent pathogen survival and spread during produce wash. These studies clearly documented risks in current practices that have been historically considered to be safe. Quantitative data were obtained to allow the FDA and industry stakeholders to employ science-based food safety guidelines and practices. Currently, a number of fresh-cut processors are already using these results to revise their wash operational parameters to provide preventive controls against pathogen transference. The team also worked closely with the industry to revise industry guidelines on fresh-cut wash operations and the HACCP food safety program, and to develop standard operational procedures to improve produce safety. In addition, we have developed a chlorine-dosing program by modeling the dynamic relationships between the incremental addition of chlorine, organic load, pH, residual free chlorine and oxygen reduction potential (ORP). This dosing program will be used to produce a novel feed-forward control of chlorine during commercial produce washing operations, thus eliminating the trial-and-error practice currently employed by industrial washing operations. We are filing for a patent application on this technology. In objective 3, we have mapped, for the first time, the multi-dimensional information of product temperature, quality, and microbial growth profiles of various produce items located in different positions (shelf height, depth), under different operational conditions over time. We shared this information with the manufacturers to help them improve the equipment performance in maintaining optimal temperatures ranges, and minimizing temperature fluctuation. Data are being compiled to design, modify and implement infrared (IR) technology to achieve an accurate and 'instant read' temperature of bagged produce. Completion of IR study will greatly facilitate in-house, third-party, state and federal government inspections by providing a method to quickly and accurately determine where temperature abuse is occurring.
Publications
- Zhou, B., Feng, H., Pearlstein, A. J. (2012). Continuous-flow ultrasonic washing system for fresh produce surface decontamination. Innovative Food Science & Emerging Technologies (In Press). DOI: 10.1016/j.ifset.2012.09.007.
- Shen, C., Luo, Y., Nou, X., Wang, Q., Millner, P. (2012). The effects of free chlorine concentration, organic load, and exposure time on the inactivation of Salmonella, Escherichia coli O157:H7 and non-O157 STEC. J. Food Protection (In Press).
- Ingram, D.T., Clark, S., Nou, X., Millner, P., Luo, Y. (2012). Evaluation of infrared technology for temperature audits of bagged leafy-green produce in retail cold-chain display. IAFP Program and Abstract Book Annual Meeting. Providence, RI
- Ingram, D.T., Millner, P., Nou, X., Luo, Y. (2012). Effect of contamination matrices on the persistence of E. coli O157 on romaine lettuce leaves. IAFP Program and Abstract Book Annual Meeting. Providence, RI
- Ingram, D. T., Zhou, B., Shen, C., Yang, Y., Sharma, M., Nou, X., Millner, P. Luo, Y. (2012). Strategies for the reduction of human pathogens in tomatoes and leafy greens: A farm to fork systems approach. American Phytopathological Society Human Pathogen on Plants Workshop. Hyattsville, MD.
- Shen, C., Luo, Y. Nou, X., Wang, Q., Millner, P. (2012). Inactivation of Salmonella, Escherichia coli O157:H7 and non-O157 STEC by hypochlorite solutions with high organic loads. IAFP Program and Abstract Book Annual Meeting. Providence, RI
- Ingram, D.T., Clark, S., Nou, X., Millner, P., Luo, Y. (2012). Optimization and evaluation of refrigerated display-case technology to maintain compliance with FDA food code regulations for fresh-cut and bagged leafy-green produce in retail cold-chain display. 23rd Annual BARC Posterday. Beltsville, MD.
- Ingram, D.T., Clark, S., Nou, X., Millner, P.D., Luo, Y. (2012). Optimization and Evaluation of Refrigerated Display-case Technology to Maintain Compliance with FDA Food Code Regulations for Fresh-cut and Bagged Leafy-Green Produce in Retail Cold-chain Display. United Fresh Produce Association Annual Meeting Abstract, Las Vegas, NV.
- Palma Salgado S, Lee H, Pearlstein A, Lou Y, Feng H. (2012). Reduction of Escherichia coli population on Iceberg and Romaine lettuce with ultrasound, sanitizer, and surfactant. Institute of Food Technologists Annual Meeting Abstract book, Las Vegas, NV.
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Progress 09/01/10 to 08/31/11
Outputs
OUTPUTS: We evaluated the effect of the sequence of washing and cutting on cross-contamination of lettuce. Concentrations of three strains of nonpathogenic E. coli O157:H7 in wash water showed similar reductions (0.5-1.0 log10CFU per ml) after wash-cut compared to current typical cut-wash sequence. Samples of inoculated red and green leaf lettuce showed 90 percent reductions in contamination after wash-cut as compared to cut-wash sequence. In addition, wash-cut sequencing delayed free chlorine depletion with fine and very fine shredded lettuce over multiple lettuce loadings compared with cut-wash sequencing. The effect of rinse to wash water ratio (14, 33, 66 percent) on free chlorine depletion and turbidity as sample to total water ratios increased (1, 2, 4.5, 6.8, 9 percent) showed improvements compared to the control (no rinse prior to wash). We also evaluated use of ultrasound, surfactants, and sanitizers in various combinations to inactivate E. coli. Acoustic power density 80 W/L of ultrasound-assisted washing at 100 ppm chlorine in batch mode reduced E. coli K12 on lettuce surfaces by 0.4-1.4 log CFU/g. Quality tests (visual inspection and conductivity) showed 5-min ultrasound treatment of lettuce had no noticeable deleterious effects compared to control over a 7-day 4C storage period. Combined use of Tsunami100 (80ppm peroxyacetic acid) and 0.5 percent sodium dodecyl sulfate significantly reduced E. coli O157:H7 on spinach. Submerged Iceberg lettuce heads increase in density after 1-min and density change is affected by water temperature. Two 12ft commercial retail, open-display produce cases provided by project cooperator Ingersoll-Rand were delivered/installed by their engineers in a USDA BL-2 facility after several months of infrastructural changes needed to fit the equipment. Case start-up was successful and initial temperature profile-maps of empty cases were obtained using temperature/humidity dataloggers distributed across the shelves. Digital thermostats were substituted for installed standard analog ones supplied so we could better regulate temperatures during tests. Case 1 (control) was set at current standard retail-operated parameters to simulate actual retail conditions; Case 2 (test) was set to evaluate updated manufacturer recommended parameters (case temperature and defrost schedule). Air-flow videography was used to map circulation patterns inside each case. Cases were designed to maintain proper holding temperatures when filled with produce, so several hundred ASTM standard fresh produce simulation bags were prepared to occupy the space that otherwise would be filled with retail product. A few additional adjustments are being made to meet specific room temperature requirements for consistent case operation. Several popular publication avenues to highlight this NIFA project research are being developed, as many industrial growers are excited to learn all the outcomes of this cooperative research project. Team economists are in the preliminary stages of the interview process to understand industrial practices, and associated costs of processing, recall, liability, and other relevant factors that may impact process costs. PARTICIPANTS: Luo, Y. (PD); Millner, P. D.(PI); Nou, X.(PI); Feng, H.(PI); Pearlstein, A. J.(PI); Bin Zhou, Yang Yang, Cangliang Shen, PhD Post-Doctoral Associates, Roc Wu, Zhenlei Xiao, Graduate Students, Yitzy Paul, Undergraduate student, Univ. MD Dept. Food Science and Nutrition; Hyounjgill Lee,PhD Post-Doctoral Associate, Sindy Palma, MS student,Department of Food Science and Human Nutrition, UIUC Partner Organizations: University of Maryland, University of Illinois at Urbana-Champaign; University of Arizona; University of California Cooperative Extension; University of Arizona; North Carolina State University; USDA-Economic Research Service; Mr. Roger Billingsley, Mr. Tom Johnson, Dole Fresh Produce; Jim Brennan, New Leaf Food Safety Solutions, Inc.; Mr. Gene Rizzo, FTNON; Mr. Tim Gutzmann/Katie Swanson, Ecolab, Inc.; Dr. Rolando Gonzalez, Target Corp.; Mr. Edmond O'Reilly, Trustwater; Ms. Sherri Clark, Ingersoll Rand. Collaborators: Dr. Beuchat(Univ. GA- Emeritus), Dr. Susan Ajeska (New Star Fresh, Salinas, CA), Dr. Roberta Cook (Univ CA-Davis-Dept. of Economics), Dr. Barry Eisenberg, UFPA, Ms. Bonnie Fernandez-Fenaroli (Center for Produce Safety), Dr. James Gorny, FDA; Dr. Bob Whitaker, PMA. TARGET AUDIENCES: Research team visited leafy green processing plants of Dole and Taylor Farms. Established collaboration with Taylor Farms for using TF pilot plant for our studies. Established collaboration with Trust Water company. Installed equipment for preparing Electrochemically Activated sanitizing solutions. Established collaboration with Ingersoll Rand-Hussmann for retail display case temperature management research. Installed commercial display cases in BL-w laboratory at USDA BARC for pathogen studies. Two new postdoctoral associates were hired at ARS-BARC. Received matching fund $98000 in cash and in-kind from Dole and other sources. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.
Impacts
The initial series of tests conducted with lettuce indicate that a pre-wash strategy prior to cutting shows major benefit relative to reducing microbial contamination and improving sanitizer efficacy by improving water quality compared with current cut-wash approaches. The potential economic benefits of prolonging free chlorine at effective sanitizer concentrations in wash water could be substantial for fresh produce processors. Ultrasound technology when combined with optimized combinations of sanitizers and surfactants shows promise for providing an additional approach for improving food safety. Reducing opportunities for temperature abuse, and hence loss of shelf-life and increased risk of microbial growth on fresh and fresh-cut product, by improved temperature control in retail display cases is of considerable interest to regulatory, commercial, and consumer communities. The evaluation of new operational parameters for fresh produce display cases widely used in retail settings throughout the USA should provide information important to retailers making decisions about equipment selection and upgrades that will improve fresh product quality, shelf-life and and safety. Our high priority is to evaluate the effects of the positive improvements of these approaches to improving food safety during fresh produce processing and retail display conditions under additional operational conditions, including pilot scales, and provide a cost-benefit evaluation along with rapid dissemination of results to commercial, regulatory, and consumer communities.
Publications
- No publications reported this period
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