Progress 01/01/04 to 09/09/99
Outputs
Significant findings: Certain foodgrade chemical solutions exhibited good potential for use as sanitizers to destroy human pathogens on the surface of fresh produce such as apples, lettuce, tomatoes, and cantaloupe. Dipping whole apples and lettuce for 2.0 minutes 5% hydrogen peroxide, sodium bicarbonate buffer (pH 11.6), or a commercial sanitizer (80 ppm Tsunami 100 or 2% PRO-SAN) at 25C significantly decreased populations of Escherichia coli O157:H7. PRO-SAN was the most effective sanitizer. Also, PRO-SAN reduced numbers of E. coli or Salmonella on tomatoes by 3.0 log (1,000-fold) compared a 2.0 log (100-fold) reduction when chlorine (200 ppm) was used. Exposure of the outer rind surface of cantaloupe to sodium bicarbonate buffer solution (pH 11.0) for 10 minutes reduced numbers of Salmonella on from 200,000 to 316 colony forming units (CFU) per rind. A much greater killing effect was achieved when rinds were exposed to a combination of 5% hydrogen peroxide and 1%
citric acid for only 2.0 minutes. Irradiation (1.0 kGy) of the outer rind surface of cantaloupe and cubes of cantaloupe flesh decreased populations of Salmonella from 5,000,000 to 910 CFU/rind and from 2,000,000 to 460 per gram, respectively. Use of a higher dose (1.5 kGy) caused further destruction of the pathogen but resulted in soft texture of the cantaloupe and increased release of juices. Initial treatment of cantaloupe rind with a combination of acidified hydrogen peroxide (5% hydrogen peroxide + 1% citric acid) and sodium lauryl sulfate (1%) followed by irradiation at 0.5 or 1.0 kGy destroyed more than 100,000 CFU of salmonellae per rind.
Impacts
Contamination of fresh produce with human enteric pathogens is a major food safety concern. Information of the effectiveness of chemical solutions for destroying pathogens on the surface of fresh fruits and vegetables will offer processors a variety of alternatives to chlorine for improving the microbial safety of these products. Effective interventions for destroying pathogens on fresh produce are crucial because currently permitted levels of chlorine can not guarantee microbial safety of fresh fruits and vegetables.
Publications
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Progress 10/01/11 to 09/30/16
Outputs
Target Audience:Target audiences (those who will be served by this project and its activities) include the general public, small, medium and large food processors, growers, wholesalers and distributors, industries, regulatory and academic personnel and both state and federal legislators. Within the university, academic personnel will benefit directly through training and dissemination of new knowledge which will impacted administrators, faculty, staff, graduate students, undergraduate students, postdoctoral researchers and visiting scholars. Academics at other institutions may also acquire new and basic knowledge from the dissemination of our results or directly through collaboration with investigators on the project. Efforts to reach the general public and other stakeholders andengage them in our work will include news coverage from College, University, local or national news services, faculty and departmental website content and student recruiting activities. Efforts to reach small, medium and large food processors and other sectors of industry will include extension and outreach activities, including direct communications, website content, presentations in training seminars, workshops or webinars or at scientific/professional meetings. Efforts to reach academic personnel will include direct personal interactions, training and development of new research techniques, processes or products developed in the course of this project, development of new teaching curricula (classroom and laboratory instruction), publication of peer-reviewed research papers, oral or poster presentations at scientific meetings and recruitment materials (presentations, flyers, website content, etc.). Changes/Problems:
Nothing Reported
What opportunities for training and professional development has the project provided?Drs. Angela Shaw and Aubrey Mendonca (1 of them) have attended the annual conference for the S-294 group in conjunction with the United Fresh Conference as professional development all five years. Dr. Shaw has been the secretary (2 years) and chair-elect (1 year) for this group and led the arrangement of the poster competition. How have the results been disseminated to communities of interest?This information has been disseminated through dissertation, seminars, short courses, workshops, webinars, and presentations at national conferences. Specifics are provided under the other product section. 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 STATEMENT: With over 230 farmers markets and 150 registered vegetable growers in Iowa, growers of fruits and vegetables are in need of new food safety intervention strategies and education to ensure the safety of their products. It is estimated that loss of fresh fruit at retail level can range from 10-25%. At Iowa State University, Drs. Wilson and Boylston have worked to identify the best methods to determine flavor and color parameters in herbs and fresh cut produce. They have also conducted shelf life studies on many different fruits and vegetables. Their recommendations to the fresh-cut industry on best methods for determining flavor, aroma, and color attributes have been presented to the produce industry (10,000 companies) through United Fresh. Adoption rates are unknown. At Iowa State University, Drs. Mendonca and Shaw have worked to identify the best produce sanitizers that can be used to improve a better quality of product in melons, peppers, leafy greens, and grapes (over 10 different products). It is estimated that over 10,000 food industry personnel have been exposed to this research through peer-reviewed journal articles, book chapters, and conference posters and oral presentations. This research has been utilized to change industry practices and has introduced new produce sanitizers into the fresh-cut industry. Human pathogens cannot be utilized in a food production setting to determine if a food safety intervention is effective. Therefore, the use of surrogate microorganisms that act like the human pathogens are critical for the fresh-cut industry to have an accurate model. We have been able to identify 5 strains of surrogate microorganisms that can be utilized for microbial risk assessment that mimic the attributes of Escherichia coli O157:H7. These strains have been cited in 12 peer-reviewed journal articles as being used in other food safety research. With so few of options available, this is a major contribution to the field of food safety. Fruit, vegetables, and nuts attribute to 46% of all the foodborne outbreaks in the U.S. each year. Even with current food safety interventions such as produce sanitizers, good agricultural practices, and employee training, there are frequent recalls and outbreaks with fresh produce that kills, hospitalizes and sickens hundreds of people. There is a continuous need to develop food safety interventions that will control for microbial contamination. At Iowa State University, Drs. Mendonca, Brehm-Stecher and Shaw have worked to develop food safety intervention strategies, conduct on-farm observational research to determine the vectors of contamination, and improve the current detection methods for identifying the human pathogens in produce. The past five years, Drs. Mendonca and Shaw have evaluated 8 different produce sanitizers as potential for killing Escherichia coli O157:H7, Salmonella spp., and Listeria monocytogenes. Dr. Brehm-Stecher has developed four different detection platforms for Salmonella spp and new methods to better find the microbes within the environment. Dr. Shaw has done an on-farm observational research and trainings to over 300 growers and has published her findings in three journal articles and four extension publications. All of this research has been presented at conferences through the U.S. and the world. It is estimated that over 10,000 food industry, academics, and government agencies have been exposed to this research. Changes in behavior after knowledge of defects has been measured by Dr. Shaw and of those surveyed (n=199) there have been 95% that have indicated that they will change their behavior in favor of a better food safety practice. These include adoption of new produce sanitizers, training, and technology. Objective 1... Evaluate methods of sampling and measuring flavor and nutrition of fresh-cut products to facilitate comparison to traditional shelf life factors. At Iowa State University, Drs. Wilson and Boylston have worked to identify the best methods to determine flavor and color parameters in herbs and fresh cut produce. They have also conducted shelf life studies on many different fruits and vegetables. Impact: It is estimated that loss of fresh fruit at retail level can range from 10-25%. Recommendations to the fresh-cut industry on best methods for determining flavor, aroma, and color attributes have been presented to the produce industry (10,000 companies) through United Fresh. Objective 2... Develop new strategies to improve and better maintain inherent fresh-cut product quality and nutrition. At Iowa State University, Drs. Mendonca and Shaw have worked to determine what are the best produce sanitizers that can be used to improve a better quality of product in melons, peppers, leafy greens, and grapes (over 10 different products). Impact: As a result of this research, peer-reviewed journal articles, book chapters, and conference posters and oral presentations have occurred. It is estimated that over 10,000 food industry personnel have been exposed to this research. This research has been utilized to change industry practices and has introduced new produce sanitizers into the fresh-cut industry. Objective 3... Determine critical factors in controlled inoculation studies with human pathogens and surrogates that influence the outcome of quantitative microbial risk assessments. At Iowa State University, Drs. Shaw and Mendonca have been working to identify potential surrogate microorganisms that can be used within a produce field setting and in a fresh-cut processing setting. To date, these two labs have been able to identify 5 strains that can be utilized for microbial risk assessment that mimic the attributes of Escherichia coli O157:H7. Impact: As a result of this results, these strains have been cited in 12 peer-reviewed journal articles as being used in other food safety research. With so few of options available, this is a major contribution to the field of food safety. Objective 4... Evaluate and control unintentional and intentional microbial contamination of intact and fresh-cut produce. At Iowa State University, Drs. Mendonca, Brehm-Stecher and Shaw have worked to develop food safety intervention strategies, conduct on-farm observational research to determine the vectors of contamination, and improve the current detection methods for identifying the human pathogens in produce. The past five years, Drs. Mendonca and Shaw have evaluated 8 different produce sanitizers as potential for killing Escherichia coli O157:H7, Salmonella spp., and Listeria monocytogenes. Dr. Brehm-Stecher has developed four different detection platforms for Salmonella spp and new methods to better find the microbes within the environment. Dr. Shaw has done an on-farm observational research and trainings to over 300 growers and has published her findings in three journal articles and four extension publications. Impact: All of this research has been presented at conferences through the U.S. and the world. It is estimated that over 10,000 food industry, academics, and government agencies have been exposed to this research. Changes in behavior after knowledge of defects has been measured by Dr. Shaw and of those surveyed (n=199) there have been 95% that have indicated that they will change their behavior in favor of a better food safety practice. These include adoption of new produce sanitizers, training, and technology.
Publications
- Type:
Book Chapters
Status:
Published
Year Published:
2013
Citation:
Mendonca, A. F., V. J. Juneja, and A. Daraba. Total Viable Counts: Metabolic Activity Tests, In Encyclopedia of Food Microbiology, 2nd edition, Batt, C.A. and M.L. Tortorello (eds.), Elsevier, Oxford, UK
- Type:
Book Chapters
Status:
Published
Year Published:
2013
Citation:
Mendonca, A. F., and A. Daraba. Non-Thermal Processing: Irradiation, In Encyclopedia of Food Microbiology, 2nd edition, Batt, C.A. and M.L. Tortorello (eds.), Elsevier, Oxford, UK
- Type:
Book Chapters
Status:
Published
Year Published:
2013
Citation:
Brehm-Stecher, B.F. Flow Cytometry, In Encyclopedia of Food Microbiology, 2nd edition, Batt, C.A. and M.L. Tortorello (eds.), Elsevier, Oxford, UK
- Type:
Book Chapters
Status:
Published
Year Published:
2013
Citation:
Brehm-Stecher, B.F. and M.L. Tortorello. Microscopic Methods, In Compendium of Methods for the Microbiological Analysis of Foods, 5th edition, Acuff, G.R. et al., (eds.), American Public Health Association, Washington, D.C.
- Type:
Other
Status:
Published
Year Published:
2013
Citation:
Shaw, A., C. Strohbehn, J. Meyer, H. Snyder, L. Wilson, B. Brehm-Stecher, and A. Mendonca. 2013. Guide to Using Liquid Sanitizer Washes with Fruits and Vegetables. Iowa State University Extension Publication. PM 1974d.
- Type:
Other
Status:
Published
Year Published:
2013
Citation:
Shaw, A., C. Strohbehn, and J. Mayer.2013.Food Pantry Produce Donations. Iowa State University Extension Publication. PM1944e.
- Type:
Other
Status:
Published
Year Published:
2013
Citation:
Strohbehn C, A Mendonca, L Wilson, P Domoto, M Smith, B Brehm-Stecher, and A Shaw. 2013. On-Farm Food Safety: Cleaning and Sanitizing Guide. Iowa State University Extension Publication. PM 1974.
- Type:
Other
Status:
Published
Year Published:
2014
Citation:
Shaw, A., C. Strohbehn, and S. Beattie. Revised 2014. Garden Produce in Floods. Iowa State University Extension Publication. SP0328
- Type:
Journal Articles
Status:
Accepted
Year Published:
2016
Citation:
Manu, D., A. Mendonca, A. Daraba*, J. Dickson, J. Sebranek, A. Shaw, and S. White. Inactivation of Escherichia coli O157:H7 and Salmonella enterica by geraniol in carrot juice and mixed berry juices at 4C and 12C. Journal of Food Protection
- Type:
Journal Articles
Status:
Published
Year Published:
2016
Citation:
Svoboda, A., A. Shaw, L. Wilson, A. Mendonca, A. Nair and A. Daraba. The effects of produce washes on the quality and shelf life of cantaloupe (Cucumis melo var. cantupensis) and watermelon (Citrullus lantus var. lanatus). Journal of Food Quality DOI:10.1111/jfq.12229
- Type:
Journal Articles
Status:
Awaiting Publication
Year Published:
2016
Citation:
Shaw, A., K. Helterbran, M.M. Evans and C. Currey. Growth of Escherichia coli O157:H7, Escherichia coli non-O157 STEC, and Salmonella spp. in water and hydroponic fertilizer solutions. Journal of Food Protection
- Type:
Journal Articles
Status:
Published
Year Published:
2016
Citation:
Svoboda A., A. Shaw, J. Dzubak, A. Mendonca, L. Wilson, and A. Nair. Effectiveness of broad spectrum chemical produce sanitizers against foodborne pathogens on cantaloupe and watermelon surfaces. Journal of Food Protection 79 (4): 524-530.
- Type:
Journal Articles
Status:
Published
Year Published:
2016
Citation:
Dzubak, J., A. Shaw, C. Strohbehn, L. Naeve, and J. Johnson. Food safety education for students and workers in school gardens and university farms. Journal of Extension 54 (1): 1TOT7.
- Type:
Journal Articles
Status:
Published
Year Published:
2016
Citation:
Roy, A., A. Shaw, L. Rajagopal, C. Strohbehn, S. Arendt, and K. Sauer. Use of minimal text posters to improve the microbial status of leafy greens and food contact surfaces in foodservice sites serving older adults. Food Protection Trends 36 (2): 123-130.
- Type:
Journal Articles
Status:
Published
Year Published:
2016
Citation:
Shaw, A., J. Dzubak, C. Strohbehn, and L. Naeve. Improving agricultural workers food safety knowledge through an online curriculum. Professional Agricultural Workers Journal 3 (2).
- Type:
Journal Articles
Status:
Published
Year Published:
2015
Citation:
Shaw A., A. Svoboda*, B. Jie***, A. Daraba* and G. Nonnecke. Importance of hand hygiene during the harvesting of strawberries. HortTechnology 25 (3):380-384.
- Type:
Other
Status:
Published
Year Published:
2014
Citation:
Paik, S., A. Mendon�a, A. Daraba, A. Shaw. Effect of starvation on resistance of Escherichia coli O157:H7 to ultraviolet radiation in 0.85% saline and in apple juice. Institute of Food Technologists Annual Meeting, June 11-14, 2014, New Orleans, LA
- Type:
Journal Articles
Status:
Published
Year Published:
2015
Citation:
Shaw-Laury, A., A. Svoboda *, B. Jie***, G. Nonnecke, and A. Mendonca. Survival of Escherichia coli on strawberries grown under greenhouse conditions. Food Microbiology 46: 200-203.
- Type:
Journal Articles
Status:
Accepted
Year Published:
2014
Citation:
Hong, S., A. Mendonca, A. Daraba, and A. Shaw. 2014. Radiation Resistance and Injury in Starved Escherichia coli O157:H7 Treated with Electron-Beam Irradiation in 0.85% Saline and in Apple Juice, Foodborne Pathogens and Disease. Accepted
- Type:
Other
Status:
Published
Year Published:
2014
Citation:
Shaw, A., L. Rajagopal, C. Strohbehn, K. Sauer, and S. Arendt. 2014. Abstract. Poster Presentation: International Association for Food Protection Annual Meeting. Microbial Assessment of Leafy Greens and Leafy Greens Contact Surfaces in Retail Foodservice Operations. Indianapolis, IN
- Type:
Other
Status:
Published
Year Published:
2014
Citation:
A. Daraba, A. Mendonca, A. Shaw, D. Manu. Viability of Salmonella enterica and Escherichia coli O157:H7 on Romaine Lettuce Following Repeated Immersion in Sanitizers With or Without Added Exudate. Institute of Food Technologists Annual Meeting, June 11-14, 2014, New Orleans, LA
- Type:
Other
Status:
Published
Year Published:
2014
Citation:
A. Daraba, Z. Adiwijaya, A. M. Shaw, and A. Mendon�a. Effectiveness of PROSAN, a Biodegradable Vegetable Wash, for killing Salmonella enterica and Escherichia coli O157:H7 on the Surface of Whole Cucumbers. United Fresh Produce Association, S-294 Science Symposium, June 11, 2014, Chicago IL
- Type:
Book Chapters
Status:
Published
Year Published:
2014
Citation:
A.Mendonca, V. Juneja, A. Daraba, Total Viable Counts - Metabolic Activity Tests, In: Encyclopedia of Food Microbiology, 2nd edition, Academic Press Ltd., London, ISBN: 978-0-12-227070-3
- Type:
Other
Status:
Published
Year Published:
2014
Citation:
Dzubak, J., A. Shaw, C. Strohbehn and L. Naeve. 2014. Abstract, Poster Presentation: International Association for Food Protection Annual Meeting. Development of an Online Food Safety Training for School Gardens. Indianapolis, IN
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2014
Citation:
Svoboda, A and A. Shaw. 2014. Oral Presentation, International Association for Food Protection Annual Meeting. Effectiveness of broad spectrum chemical intervention treatments against foodborne pathogens on artificially inoculated cantaloupe and watermelon. Indianapolis, IN
- Type:
Other
Status:
Published
Year Published:
2014
Citation:
Shaw, A., A. Svoboda, A. Mendonca, and S. Jung. 2014. Abstract, Poster Presentation: International Association for Food Protection Annual Meeting. Search for a natural intervention against L. monocytogenes in Wheatgrass Juice. Indianapolis, IN
- Type:
Book Chapters
Status:
Published
Year Published:
2014
Citation:
A. Mendonca, A. Daraba, Non-Thermal Processing Irradiation, In: Encyclopedia of Food Microbiology, 2nd edition, Academic Press Ltd., London, ISBN: 978-0-12-227070-3
- Type:
Theses/Dissertations
Status:
Published
Year Published:
2013
Citation:
Seaman, M. Sodium Polyphosphate Enhances the Antimicrobial Activities of Whole and Fractionated Peanut Skin Extract against Zygosaccharomyces bailii in a Model Juice System, MS Thesis, Iowa State University, May, 2013
- Type:
Other
Status:
Published
Year Published:
2013
Citation:
Brehm-Stecher, B.F. Abstract, Poster Presentation: Flow Cytometry for Rapid Detection of Foodborne Pathogens, In Symposium on "Emerging Technologies for Detection and Characterization of Foodborne Pathogens, A. Bhunia and B. Brehm-Stecher, Organizers/Conveners, International Association for Food Protection Annual Meeting, Charlotte, NC, July 30, 2013
- Type:
Other
Status:
Published
Year Published:
2013
Citation:
Seaman, M. Abstract, Poster Presentation: Sodium Polyphosphate Enhances the Antimicrobial Activities of Whole and Fractionated Peanut Skin Extract against Zygosaccharomyces bailii in a Model Juice System, International Association for Food Protection Annual Meeting, Charlotte, NC, July 31, 2013
- Type:
Other
Status:
Published
Year Published:
2013
Citation:
Zhang, Z., Mendonca, A., Brehm-Stecher, B., and L.A. Wilson. Abstract, Poster Presentation: Natural Antimicrobial Systems for Inhibition of Pathogens on Fresh Produce. USDA-NIFA/NIFSI grant 2009-51110-05902 meeting, Columbus, OH, September 12th, 2013.
- Type:
Other
Status:
Published
Year Published:
2013
Citation:
Svoboda. A and A. Shaw. Abstract, Poster Presentation: Effectiveness of Chemical Intervention Treatments against E. coli O157:H7, Non-O157 STEC, Listeria monocytogenes, and Salmonella. International Association for Food Protection Annual Meeting, Charlotte, NC, July 30, 2013.
- Type:
Other
Status:
Published
Year Published:
2013
Citation:
Ortiz, A., Zuercher A.,Adiwijaya, Z.,Daraba, A.,Shaw, A., and A. Mendon�a. Abstract, Poster Presentation: Inactivation of Salmonella enterica and Escherichia coli O157:H7 on whole Cucumbers by immersion in PRO-SAN, a Biodegradable Food grade Sanitizer. George Washington Carver Research Program, summer 2013
- Type:
Book Chapters
Status:
Published
Year Published:
2013
Citation:
Soo, Hwan Suh, Brehm-Stecher, B. and L.-A. Jaykus. 2013. Advances in Separation and Concentration of Microorganisms From Food Samples, In Advances in Microbial Food Safety, J. Sofos (ed), Woodhead Publishing, Cambridge, UK
- Type:
Book Chapters
Status:
Published
Year Published:
2013
Citation:
Brehm-Stecher, B.F. 2013. Advances in Single-Cell Approaches for the Study of Foodborne Pathogens, In Advances in Microbial Food Safety, J. Sofos (ed), Woodhead Publishing, Cambridge, UK
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Progress 01/01/12 to 12/31/12
Outputs
OUTPUTS: Our team completed a combination of research and extension workshops and activities in 2012 to account for our time. Drs. Shaw and Mendonca completed a survivability study with strawberries and romaine lettuce in the summer of 2012. Within this study, five strains on Escherichia coli non-O157:H7 (O26, O103, O111, O121 and O145) were evaluated for their ability to survive during post-harvest storage. It was discovered during this experiment that there were significant strain difference over the 6 day shelf life study with growth of between 1-4 log cycles depending on the produce type and strain. This study has led to a follow up study that will be completed within 2013. Drs. Shaw and Mendonca also completed a series of studies with wheat grass and the wheat grass juice products for a local grower. The goal for the grower was to determine if there was a post juicing method that could be used to deliver a 5 log Listeria reduction required for bottling. Although this is on-going series of projects with additional ingredient supplements and processes being tested, our preliminary results indicate that the wheat grass and the juice are an excellent media for growth of spoilage organisms and foodborne pathogens when present. Dr. Shaw's lab completed a series of strawberry experiments in 2012. Her lab evaluated the influence of hand hygiene on post-harvest handling along with the survivability of E.coli during the pre-harvest growing. It was concluded during her studies that E.coli O157:H7 has the ability to be transferred from contaminated hands to at least 100 strawberries during normal picking and that the transfer of bacteria can be observed as far as 50 feet from the edge of a field. Another observation was that the workers have the potential to transfer the bacteria onto their clothing and skin during the harvesting process. Within the survivability portion of the project, E.coli was able to survive in the soil, on the leaves, and on the fruit from impact to harvest but the greatest survivability on the strawberry fruit occurred when water contamination happened within the last month of growing. In addition to performing research, Drs. Shaw and Wilson were active with extension and outreach to provide guidance to growers on Good Agricultural Best Practices (GAP). Dr. Shaw and colleagues provided five full-day GAP training courses to growers throughout the state which impacted 113 different farms. Another extension and outreach activity occurred in the summer of 2012 where Drs. Wilson and Shaw travelled to The Ohio State University to participate within a Leafy Greens safety short course hosted by Drs. Gonul Kaletunc and Sudir Sastry. During this training both extensions specialist and growers learned about concerns related to leafy greens and some of the most recent research out of The Ohio State University. A follow-up planning meeting occurred in the fall of 2012 at Iowa State University in which representatives from Iowa State University, The Ohio State University, and New Mexico State University met to discuss their most recent research projects and plans for future collaboration efforts. PARTICIPANTS: Dr. Angela Shaw, Principal investigator on survival of non-O157 STEC on strawberries and lettuce (Co-PI's Dr. Aubrey Mendonca). Dr. Angela Shaw, Principal investigator wheat grass surveillance (Co-PI's Dr. Aubrey Mendonca). Dr. Angela Shaw, Principal investigator on Cross contamination of E.coli O157:H7 from handler's hands to strawberries during collection and survivability during growth (Co-PI's Gail Nonnecke). Dr. Angela Shaw, Principal investigator on GAP training (Co-PI Drs. Lester Wilson, Cathy Strohbehn, Paul Domoto, Teresa Wiemerslage and Margaret Smith, Value Added Agriculture, Iowa State University). Drs. Sudir Sastry (Ohio State, PI), Lester Wilson (Iowa State, Co-PI), Aubrey Mendonca (Iowa State, Co-PI), Byron Brehm-Stecher (Iowa State), Gonul Kaletunc (Ohio State), Jeanne Gleason (New Mexico State), Amy Smith Muise (New Mexico State University) on The Physics of Leafy Greens Additional train the trainer activities were provided to Extension and Outreach personnel and local grower organizations to learn more about food safety concerns on farm (228 were in attendance of various webinars and workshops) TARGET AUDIENCES: Growers, packers, and processors of fruits and vegetables, extension and outreach specialists, academia, federal food agencies, and consumers PROJECT MODIFICATIONS: No major project modifications in 2012
Impacts
With over 230 farmers markets and 150 registered vegetable growers in Iowa, growers of fruits and vegetables are in need of new food safety intervention strategies and education to ensure the safety of their products. The research experiments completed on strawberries, lettuce, wheatgrass and wheatgrass juice all provided information to fill in gaps within knowledge of foodborne bacteria. Additionally, these studies have highlighted the critical areas with the growing process that can reduce the prevalence of foodborne bacteria thus reducing consumer risk. The Good Agricultural Best Practice workshops reached over 100 growers and educators throughout the state of Iowa. These workshops increased the knowledge required for decision-making, while providing practical suggestions for good agricultural best practices. Educating our farmers about farm management options that impact the risk of a foodborne outbreak is critical for our programing.
Publications
- No publications reported this period
|
Progress 01/01/11 to 12/31/11
Outputs
OUTPUTS: Drs. Mendonca, Terri Boylston, and Lester Wilson performed experiments to identify practical produce rinse solutions to reduce Salmonella in whole tomatoes, Serrano peppers, and leafy lettuce. These experiments demonstrated that PRO-SAN, a bio gradable food grade sanitizer, was able to reduce Salmonella on the surface of whole tomatoes, Serrano peppers and romaine lettuce. In the pepper study, immersion in water and CL resulted in 1.0 and 1.66 log reductions of the pathogen, respectively. Log reductions on peppers treated with PRO-SAN, and its derivatives ranged from 3.08 to 3.89. Increasing the exposure time of peppers to treatment solutions did not significantly increase inactivation of the pathogen. Similarly with whole tomatoes and romaine lettuce, PRO-SAN was able to reduce Salmonella by 1 to 2 logs when immersed for 1 minute. In the lettuce study, results indicated that the dry control, distilled water control, and 150 ppm bleach solution were not significantly different from each other, but were less effective than the PRO-SAN, solutions when the treatments were tested at room temperature. PRO-SAN in these experiments did not adversely affect the quality parameters (color and sensory panel) of the food types and were seen as acceptable intervention strategies. Dr. Brehm-Stecher conducted two experiments in rapid detection technology for foodborne pathogens in many matrices including produce. His research created a novel vacuum based foam extraction system to remove Salmonella from surfaces and a hollow fiber concentration and molecular analysis via real-time PCR methodology. This approach enables effective removal of bacteria present on bulk surfaces and allows sampling of substantially larger areas than is possible with swab-based methods. The combined use of foam-based vacuum extraction and subsequent ultra-concentration enables rapid testing of bulk surfaces for low levels of pathogens. This approach provides a macro-to-micro coupling during the sampling process, allowing concentration of contaminant cells into microliter-scale sample volumes compatible with molecular testing methods such as PCR. Dr. Brehm-Stecher also created a new method, Chemical Restriction Length Polymorphism (CLFP) for the rapid characterization of bacterial pathogens. This technology uses primer labels to enable detection and high-resolution analysis of Salmonella. Dr. Brehm-Stecher disseminated these results at four conferences over the summer of 2011 and led a symposium on rapid detection methods. In addition to performing research, Drs. Shaw and Wilson were active with extension and outreach to provide guidance to growers on Good Agricultural Best Practices (GAP). Dr. Wilson and colleagues provided two full-day GAP training courses (that included mock inspection demonstrations) to growers and two additional 4-hour GAP workshops for growers wanting to sell to institutions. At the end of 2011, Drs. Shaw and Mendonca held both in-person sessions and a webinar on the Food Safety Modernization Act and the impact on growers. Within these sessions 75 growers and educators were impacted by the information delivered. PARTICIPANTS: Dr. Aubrey Mendonca, principal investigator on PRO-SAN for tomatoes and serrano peppers (Co-PI's Dr. Aura Daraba, Associate Professor, University Dunarea de Jos, Galati, Romania, David Manu, Masters student Iowa State University, and Dr. Floyd Woods, Associate Professor, Auburn University). Dr. Lester Wilson, principal investigator on PRO-SAN for romaine lettuce (Co-PI Drs. Aubrey Mendonca, Byron Brehm-Stecher, Terri Boylston, and Julianne Drury, masters student, Iowa State University), and principal investigator on GAP training (Co-PI Drs. Cathy Strohbehn, Paul Domoto, Angela Shaw and Margaret Smith, Value Added Agriculture, Iowa State University). Dr. Angela Shaw principal investigator on Food Regulation Updates (Co-PI Dr. Aubrey Mendonca). Dr. Bryon Brehm-Stecher, principle PI on three rapid detection methodologies (Co-PI Dr. Kim, Post-Doctoral Researcher, Iowa State University). TARGET AUDIENCES: Growers, packers, and processors of fruits and vegetables, food manufacturers, microbiological technology companies, extension and outreach specialists, academia, federal food agencies, and consumers. PROJECT MODIFICATIONS: Not relevant to this project.
Impacts
With over 230 farmers markets and 150 registered vegetable growers in Iowa, growers of fruits and vegetables are in need of new food safety intervention strategies and education to ensure the safety of their products. PRO-SAN in these experiments was seen to be an effective food safety intervention strategy against Salmonella in romaine lettuce, tomatoes, and Serrano peppers. These results were able to provide additional information to growers and provide an opportunity for growers to change their post-harvest food safety practices. The Good Agricultural Best Practice workshops reached over 100 growers and educators throughout the State of Iowa. These workshops increased the knowledge required for decision-making, while providing practical suggestions for good agricultural best practices. It was observed through these training sessions that there is a need for continuing education for these professionals, as well. Findings also indicated the growing need for food safety checklists, verification of safety protocols implemented, and third party audit information. Findings also suggest that requirements by wholesale buyers will continue to drive the need market for food safety and auditing information. These findings initiated the formation of a multi-discipline On-Farm Food Safety team to aid in extension and outreach education on food safety and production practices. Dr. Brehm-Stecher discovered three novel rapid detection technologies (Pre-analytical extraction, foam/vacuum extraction and hollow fiber detection, and chemical restriction fragment length polymorphism detection) that can be utilized with many types of foods. The results from his technology will impact the food industry by providing innovative techniques that can improve food pathogen detection, change the response time for microbial results, and change the rate of information transfer. These detection technologies can aid in the reduction of food borne illness burden in the U.S. by prompting recall notifications faster. His discovery of new primer will aid microbiologists in improving other microbial techniques that require PCR technology.
Publications
- Mendonca, A., A. Daraba, D. Manu, and F. Woods. 2011. Inactivation of Salmonella enterica On Whole Tomatoes and Serrano Peppers Immersed In Pro-San, a Biodegradable Vegetable Sanitizer. Journal of Environmental Protection and Ecology, ISSN 1311-5065, Book II, pp.769-780.
- Brehm-Stecher, Byron. 2011. Rapid Detection of Pathogens in Complex Food Matrices. IFT Session Abstract, New Orleans, LA and Sample Prep 2011, San Diego, CA and Society for Laboratory Automatic, Palm Spring CA.
- Brehm-Stcher, Byron. June 30th-July 1st, 2011. Chemical Restriction Length Fragment Polymorphism (CRLFP) for Detection and Characterization of Bacterial Pathogens. Advances in Biotedetecion & Biosensors, European Lab Automation Meeting, Hamburg, Germany Abstract.
- Brehm-Stecher, B., M. Tortorello, and L. Jaykus. 2011. Symposium Originator and Co-Convenor: From Farm to Fork to Physician: Detection of Human Pathogens in the Environment, in Foods and in Clinical Specimens. International Association for Food Protection Annual Meeting, Milwaukee, WI.
- Kim, H.J. and B. Brehm-Stecher. June 16th-17th, 2011. Foam/Vacuum Extraction and Hollow Fiber Concentration for Detection of Foodborne Pathogens. NSF Conference on Novel Sampling and Sensors for Improving Food Safety, Georgia Tech, Atlanta, GA.
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Progress 01/01/10 to 12/31/10
Outputs
OUTPUTS: Experiments were performed to improve the microbial safety of fresh produce by destroying enteric pathogens (Salmonella enterica, Escherichia coli O157:H7 and Listeria monocytogenes ) on their surfaces using a foodgrade sanitizer or natural antimicrobials from value-added agricultural waste products . The results demonstrate that more than 1,000-fold reduction in numbers of viable pathogens (Salmonella and E. coli) on Romaine lettuce can be attained following immersion of lettuce for two or four minutes in 1 percent PROSAN, a biodegradable foodgrade sanitizer. The far superior antibacterial ability of PROSAN compared to the commonly used chlorine (150 ppm) against the pathogens on lettuce was also demonstrated. Results of experiments on use of grape seed extract (GSE) to sanitize the whole tomatoes indicated that more than 100-fold destruction in numbers of viable listeriae occurred on the surface of the tomatoes immersed in GSE at1250 ppm. An adhesive-tape-based method followed by on-tape fluorescence in situ hybridization (FISH) was developed for rapid detection of Salmonella spp on the surfaces of fresh produce without having to grow the pathogen in culture media. This detection method provides a simple and rapid sampling and detection of Salmonella on fresh produce. Procedures to produce sweetened apple cider with 6.5 percent alcohol and 8 degrees Brix were developed. Quality tests indicated that cider from Golden Delicious apples was sweeter than ciders of Gold Rush, Liberty, Jonathan, Chieftain or MacIntosh apples and less sour than Gold Rush, Liberty, Jonathan or MacIntosh ciders. Cider blends of Golden Delicious and MacIntosh apples had greater sweetness, less sourness and more apple flavor than blends of MacIntosh and Fireside or MacIntosh and Jonathan apples. Research activities on improving the microbial safety of fresh produce fostered collaborations with faculty at University "Dunarea de Jos" in Galati, Romania. Based on this collaboration a presentation was given to fresh produce growers and packers at the United Fresh Produce Association meeting in 2010. The presentation included a sanitization method that packers can easily apply to sanitize the surfaces of fresh produce. The dissemination of additional research methods and results was accomplished through peer-reviewed publications, presentations at professional scientific meetings, published abstracts and on-line regional project reports. PARTICIPANTS: Byron Brehm-Stecher, Ph.D. principal investigator on: Flow cytometric detection of microbes in foods, selective capture, concentration and visual molecular detection of pathogens from foods (Bledar Bisha, Ph.D. candidate, graduate student. Cheryll Reitmeier, Ph.D., Co-investigator on: development of a prototype on-farm system for producing hard cider. Aubrey F. Mendonca, Ph.D., principal investigator on: Improving the microbial safety of fresh and fresh-cut fruit and vegetables (David Manu, M.S. graduate student). Collaborators or contacts: Aura Daraba, Ph.D., Associate Professor, University "Dunarea de Jos", Galati, Romania. TARGET AUDIENCES: Growers, packers, and processors of fresh-cut fruit and vegetables, apple growers, apple cider processors, food scientists in industry and academia, federal food agencies, and consumers. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.
Impacts
Food processors became aware of the efficacy of PRO-SAN and grape seed extract for killing pathogenic bacteria on the surfaces fresh vegetables and fruits. Processors that use these sanitization methods could expect improved microbial safety of fresh produce for consumers. Approximately seventy nine tons of grape seeds are generated as waste from wine production in Iowa. This yields about twelve tons of grape seed oil from which grape seed extract could be produced for use as surface sanitizer for fresh produce. Through presentations by ISU Extension personnel, Iowa apple growers have become aware of the procedures for producing hard apple cider. Production of hard cider has good potential for generating an addition line of income for apple growers and cider sales may compete successfully with national cider brands in regions of Iowa. Through applied research activities food scientists at Iowa State University gained knowledge on improved methods for detecting and destroying pathogens on fresh produce. Fresh produce growers, processors and packers have become aware of more effective procedures to sanitize the surfaces of fresh fruits and vegetables. If implemented, the procedures for killing human enteric pathogens on produce items will improve the microbial safety of fresh-cut vegetables and fruits for consumers.
Publications
- Bisha, B., Weinsetel, N., Brehm-Stecher, B.F. and Mendonca, A. 2010. Antilisterial effects of Gravinol-S grape seed extract at low levels in aqueous media and its potential application as a produce wash. J. Food Prot. 73: 266-273.
- Bisha, B., Brehm-Stecher, B.F. 2010. Combination of Adhesive-tape-based Sampling and Fluorescence in situ Hybridization for Rapid Detection of Salmonella on Fresh Produce. J. Vis. Exp. (44), e2308, DOI: 10.3791/2308.
- Mendonca, A., Manu, D., Daraba, A, and Brehm-Stecher, B. F. 2010. Fate of Salmonella enterica and Escherichia coli O157:H7 on Romaine lettuce following immersion in PRO-SAN- a biodegradable, foodgrade sanitizer. In Abstracts of S-294 Science Symposium and United Fresh Produce Association Annual Meeting, Las Vegas, NV. April 2010
- Reitmeier, C. A., Wilson, L. A., and Gleason, M. R. 2010. Sensory evaluation of hard apple cider. In Abstracts of The Institute of Food Technologists Annual Meeting, Chicago, IL, July 2010
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Progress 01/01/09 to 12/31/09
Outputs
OUTPUTS: Experiments were conducted on application of food grade chemical sanitizers, functional food ingredients, antimicrobials derived from value-added agricultural waste streams, and multicomponent antimicrobial systems for killing or detaching pathogens on fresh produce, including tomatoes and Jalapeno or Serrano peppers. The results demonstrate that significant reductions (1,000-fold) of viable Salmonella enterica on tomatoes and Jalapeno peppers can be achieved by immersing the produce for 2 to 4 minutes in 1% PRO-SAN, a biodegradable, foodgrade sanitizer. Populations of viable Listeria species on the surface of whole tomatoes are decreased 100-fold by immersing tomatoes for 2 minutes in grape seed extract (0.125%) at ambient temperature. These results document the feasibility of using certain agricultural waste products with antimicrobial properties for decontaminating the surface of whole tomatoes. Studies were performed to develop processes for making hard cider that is consistently rated higher in quality than the top commercial brands. Evaluation of hard cider made from Iowa-grown apple cultivars revealed that the appearance, color and flavor of cider made from 'MacIntosh' apples was superior to cider from other cultivars. A blend of ciders made from 'Golden Delicious' and 'Jonathan' apples resulted in excellent cider. Experiments were conducted to develop novel pre-analytical food sample preparation techniques that can be used with sensitive and specific methods for detection of foodborne pathogens. A method was developed for rapid cytometric detection of Salmonella Saintpaul on Jalapeno peppers. The use of small volumes of non-selective growth media to amplify low numbers of Salmonella from the surface of the peppers allows rapid detection of the pathogen by flow cytometry. Also, a method based on flow-through imaging cytometry facilitates rapid detection of Salmonella spp among non-target microorganisms and particulate matter in contaminated alfalfa sprouts. A simple adhesive tape-based method for pathogen sampling and analysis was developed for detection and characterization of Salmonella spp. Jalapeno peppers, tomato, cilantro and spinach surfaces. Our collaboration with Advanced Analytical Technologies, Ames, IA resulted in development of a method for rapid (~3 h) determination of pathogen DNA sequence information, as an alternative to direct DNA sequencing. This approach may ultimately be useful for rapid identification and source tracking of pathogens associated with fresh produce. Research activities on food sample preparation methods fostered collaborations with colleagues at the Food and Drug Administration, The Johns Hopkins Applied Physics Laboratory and North Carolina. The collaboration resulted in the writing of an authoritative review on methods for pre-analytical sample preparation, including approaches that can be adopted from other disciplines, such as food or analytical chemistry. Research methods and results were disseminated through presentations at professional scientific meetings, peer-reviewed publications, published abstracts, and on-line regional project reports. PARTICIPANTS: Byron Brehm-Stecher, Ph.D. principal investigator on: Flow cytometric detection of microbes in foods, selective capture, concentration and visual molecular detection of pathogens from foods (Bledar Bisha, Ph.D. candidate, graduate student); atomic force microscopy for deposition of antimicrobial polymer arrays (Heidi Weinkauf, Ph.D. candidate; graduate student). Cheryll Reitmeier, Ph.D., Co-investigator on: development of a prototype on-farm system for producing hard cider. Aubrey F. Mendonca, Ph.D., principal investigator on: Improving the microbial safety of fresh and fresh-cut fruit and vegetables. Collaborators or contacts: Floyd F. Woods, Ph.D., Associate Professor, Department of Horticulture, Auburn University; Aura Daraba, Ph.D., Associate Professor, University "Dunarea de Jos", Galati, Romania. TARGET AUDIENCES: Growers, packers, and processors of fresh-cut fruit and vegetables, apple growers, apple cider processors, food scientists in industry and academia, federal food agencies, and consumers. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.
Impacts
Processors and packers of fresh-cut produce became aware of the effectiveness of PRO-SAN and of the value-added plant antimicrobial grape seed extract against pathogenic bacteria on fresh produce surfaces. Processors that adapt those decontamination technologies could expect to enhance the microbial safety of their fresh produce for consumers. Based on an annual Iowan wine production of 280,000 gallons, an estimated 79.8 tons of grape seeds are produced as waste, which further generates ~12 tons of purified grape seed oil from which grape seed extract could be produced for promoting microbial safety of fresh produce. Approximately 50 Iowa apple growers have become aware of the procedures for hard apple cider production via ISU Extension presentations. Hard cider may provide an addition source of income for apple growers and may compete successfully with national cider brands in their own regions. Through research activities, fundamental knowledge on pathogen detection and inactivation via chemical and natural antimicrobial means is being acquired by S-294 scientists at Iowa State University. The fresh-cut produce industry has been made aware of alternative methods for sample preparation and pathogen detection using novel molecular approaches. If adopted by the fresh produce industry, food sample preparation methods that enable effective extraction, separation and concentration of target pathogens are expected to enhance pathogen detection on produce or in produce processing environments.
Publications
- Mendonca, A., Brehm-Stecher, B.F., Dutilly, D. and Manu, D. 2009. Destruction of Salmonella enterica on whole tomatoes and Jalapeno peppers by immersion in PRO-SAN, a biodegradable, foodgrade sanitizer. In: Abstracts of Conference of Food Engineering (COFE), Columbus, OH. April 2009.
- Bisha and Brehm-Stecher, B.F. 2009. Washing and enrichment of Jalapeno peppers using small volumes of non-selective broth facilitates rapid cytometric detection of Salmonella Saintpaul. In: Abstracts of S-294 Science Symposium and United Fresh Produce Association Annual Meeting, Las Vegas, NV. May 2009.
- Bisha, B., and Brehm-Stecher, B.F. 2009. Simple Adhesive Tape-Based Sampling of Tomato Surfaces Combined with Rapid Fluorescence In Situ Hybridization for Detection of Salmonella. Appl. Environ. Microbiol. 75: 1450-1455.
- Bisha, B. and Brehm-Stecher, B.F.. 2009. Flow-through imaging cytometry for detection of Salmonella spp. in alfalfa sprouts, a microbiologically complex food system. Biotechnol. J. 4: 880-887.
- Brehm-Stecher, B.F., Young, C., Jaykus, L.-A. and Tortorello, M.L. 2009. Sample preparation: the forgotten beginning J. Food Prot. 72: 1774-1789.
- Mendonca, A., Daraba, A., and Manu, D. 2009. Inactivation of Salmonella enterica on whole tomatoes and Serrano peppers immersed in PRO-SAN, a biodegradable vegetable sanitizer. In: Abstracts of International Conference of Sustainable Development in Southeast Europe, Tekirdag, Turkey June 16-18, 2009.
- Porter, B., Wei, W., Pang, H-M. and Brehm-Stecher, B.F. 2009. DNA Profiling for Characterization of Salmonella spp. In: Abstracts of American Society for Microbiology's General Meeting, Philadelphia, PA. June 2009.
- Bisha and Brehm-Stecher, B.F. 2009. Washing and enrichment of Jalapeno peppers using small volumes of non-selective broth facilitates rapid cytometric detection of Salmonella Saintpaul. In: Abstracts of International Association for Food Protection's Annual Meeting, Grapevine, TX. July 2009.
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Progress 01/01/08 to 12/31/08
Outputs
OUTPUTS: Experiments were conducted to improve detection of foodborne pathogens and control pathogens in fresh produce and tree nuts. Two methods namely, Capillary electrophoresis (CE) and fluorescence in situ hybridization (FISH), were combined to develop a novel rapid approach in pathogen detection. This new sensitive method specifically detects and differentiates Salmonella from Escherichia coli in mixed bacterial populations in a relatively short time (10 to 15 minutes). A simple detection method for Salmonella on whole tomatoes was developed using adhesive tape and FISH. Salmonella on fresh-cut cantaloupe melon is destroyed with low-dose electron beam irradiation (0.75 or 1.0 kGy) without negatively altering texture, color or nutrient content of the melon. Based on our work on irradiation of cantaloupe to destroy pathogens, a partnership was formed with the Department of Horticulture at Auburn University to research the impact of irradiation treatment on selected quality attributes and microbial safety of fresh produce. More that 1,000-fold reduction in numbers of viable Salmonella on whole almonds is achieved by use of high hydrostatic pressure when almonds are directly suspended in water. Research methods and results were disseminated through presentations at professional scientific meetings, peer-reviewed publications, published abstracts, and on-line regional project reports. PARTICIPANTS: Individuals: Byron Brehm-Stecher, PhD, principal investigator on: Flow cytometric detection of microbes in foods, selective capture, concentration and visual molecular detection of pathogens from foods (Bledar Bisha, PhD candidate, graduate student); Development and evaluation of multicomponent antimicrobial systems (essential oil-based and biomimetic polymer-based) (Heidi Weinkauf, PhD candidate, graduate student); Atomic force microscopy for deposition of antimicrobial polymer arrays (Heidi Weinkauf, PhD candidate, graduate student). Aubrey Mendonca, PhD, principal investigator on: Improving the microbial safety of fresh and fresh-cut melons. Collaborators or contacts: Floyd F. Woods, Ph.D., Associate Professor, Department of Horticulture, Auburn University, Auburn, AL. TARGET AUDIENCES: Growers, packers and processors of fresh-cut fruit and vegetables, educators, food scientists in industry and academia, federal food agencies, and consumers. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.
Impacts
The novel CE-FISH detection method overcomes provides a promising new tool for molecular detection of specific bacterial cells present in mixed populations. It overcomes the limitation of use of CE alone which cannot differentiate closely related species of bacterial pathogens having similar surface charge profiles. The tape-FISH method is faster than conventional detection methods for Salmonella because use of adhesive tape to physically remove microbial cells from the surface of the tomatoes drastically reduces the sample preparation time. Low dose electron beam irradiation offers processors the advantage of destroying pathogens in already packaged fresh-cut cantaloupe melon while maintaining fresh-like product quality. Due to the delicate nature of fresh-cut melon it is not impractical to use various types of chemical antimicrobials and maintain fresh-like characteristics of the produce. Also following chemical treatment the melon still has to be packaged for distribution. High hydrostatic pressure destruction of pathogens on certain dry foods such as tree nuts is feasible when the product is suspended directly in the pressure-transmitting medium (water). Effective detection and control methods for produce-borne pathogens will ensure the microbial safety of fresh-cut vegetables, fruits, and tree nuts for consumers without compromising produce quality characteristics.
Publications
- Lantz, A. W., Brehm-Stecher, B. F., and D. W. Armstrong. 2008. Combined Capillary Electrophoresis and DNA-FISH for Rapid Molecular Identification of Salmonella Typhimurium in Mixed Culture. Electrophoresis 29: 2477-2484.
- Wilford, J., A. Mendonca, and L. Goodridge. 2008. Water pressure effectively reduces Salmonella Enteritidis on the surface of raw almonds. J. Food Prot. 71(4):825-829.
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Progress 01/01/07 to 12/31/07
Outputs
OUTPUTS: A DNA-based fluorescence in situ hybridization (FISH) method combined with flow cytometry (CM) has been developed for detection of Salmonella in seed sprouts. Improved destruction of Salmonella on the outer rind surface of cantaloupe was achieved by use chemicals and electron beam irradiation. Results were presented at the Annual Meeting of the United Fresh Produce Association in Palm Springs, CA, 2007. (Audience: growers and processors of fresh-cut fruits and vegetables)
PARTICIPANTS: Aubrey Mendonca and Byron Brehm-Stecher are Associate Professor and Assistant Professor, respectively, in the Department of Food Science and Human Nutrition (FSHN). Bledar Bisha is a graduate student in FSHN.
TARGET AUDIENCES: Processors of fresh-cut fruits and vegetables
PROJECT MODIFICATIONS: None
Impacts
The FISH/CM method facilitates rapid (in one hour) detection of Salmonella in seed sprouts. With this method processors can quickly evaluate the safety of sprouts and prevent sprout-related outbreaks of salmonellosis. Acidified hydrogen peroxide/surfactant solutions and irradiation produces a higher (100-fold) level of destruction of Salmonella on cantaloupe rind compared to currently used chlorine solutions to improve microbial safety of the fresh-cut cantaloupe.
Publications
- Bisha, B., Brehm-Stecher, B. F. 2007. Rapid Detection of Salmonella spp in Seed Sprouts via Flow Cytometry. In Abstracts of the S-294 Regional Project Science Symposium and International Fresh Produce Association Meeting, Palm Springs, CA, April 27-29.
- Mendonca, A. F. and Orozalieva, A. 2007. Sequential application of chemical and irradiation treatments to destroy Salmonella spp and Escherichia coli O157:H7 on the outer rind surface of cantaloupe. In Abstracts of the S-294 Regional Project Science Symposium and International Fresh Produce Association Meeting, Palm Springs, CA, April 27-29, 2007.
- Brehm-Stecher, B.F. 2007. New Technologies for Imaging Individual Microbial Cells in Imaging Cellular and Molecular Biological Function, F. Frischknecht and S. Shorte, (eds.) Springer-Verlag, Berlin.
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Progress 01/01/06 to 12/31/06
Outputs
The use of DNA-based fluorescence in situ hybridization (FISH) combined with flow cytometry provided a method to rapidly detect Salmonella Typhimurium in artificially contaminated alfalfa and other seed sprouts. Hybridization times were as short as 30 min and S. Typhimurium was detectable in sprout wash water at levels as low as 103 CFU/ml against high populations of background microorganisms (108 CFU/g sprouts). A combination of lactic acid (LA) and sodium lauryl sulfate (SLS) was effective in killing enteric pathogens on raw whole almonds. LA (5%) reduced viable numbers of Salmonella Enteritidis, Escherichia coli O157:H7 and Listeria monocytogenes by 1.18, 1.16, and 1.49 log, respectively. Log reductions after dipping in SLS were 1.09 (S. Enteritidis), 1.20 (E. coli O157:H7) and 1.77 (L. monocytogenes). In contrast, 5% LA + 2% SLS reduced numbers of S. Enteritidis, E. coli O157:H7 and L. monocytogenes by 3.54, 3.45, and 4.62 log, respectively. Hydrogen peroxide (5%
HP) or sodium lauryl sulfate (1% SLS), alone or in combination, was effective in killing Salmonella spp and Escherichia coli 0157:H7 on whole cantaloupe. HP (5%) reduced numbers of Salmonella and E. coli by 2.73 and 2.82 log CFU, respectively. Further reductions were achieved by combining 5% HP with 1% SLS; populations of Salmonella and E. coli decreased by 3.37 and 3.15 log, respectively. Viable numbers of the pathogens were reduced by only 1.06 to 1.20 log after exposure to 200 ppm sodium hypochlorite. PRO-SAN, an EPA-approved, food grade sanitizer reduced initial populations of pathogens on artificially inoculated teflon-coated Kevlar (TCK), Teflon (TEF), coated Teflon (CTEF), Kevlar (KEV) and Nomex (NOM). Reductions in pathogen populations on plastic-type materials for the vegetable growth chamber (TCK, TEF, and CTEF) and root mat materials (KEV and NOM) following immersion in water ranged from 0.2 to 1.85 and 0.6 to 0.52 log CFU/sample, respectively. In contrast, exposure of
samples to PRO-SAN resulted in reductions of 2.88 to 4.50 and 4.21 to 5.75 log CFU/sample on the plastics and root mat materials, respectively. Generally, S. aureus and L. monocytogenes were more sensitive to PRO-SAN than Salmonella or E. coli O157:H7 irrespective of the type of material tested. For each pathogen, log reductions were consistently higher on KEV compared to NOM; however, differences were not significant.
Impacts
Expected Impact: DNA-based fluorescence in situ hybridization (FISH) combined with flow cytometry will enable rapid detection of Salmonella in fresh produce. The approach helps processors to quickly determine the safety of ready-to-eat vegetables and prevent costly product recalls. Washing fresh produce with solutions of organic acid or hydrogen peroxide plus a surfactant produces a greater (10-fold) level destruction of pathogenic bacteria compared to the commonly used chlorine wash solutions. The use of PRO-SAN offers processors an intervention step to destroy enteric pathogens that fresh produce might be exposed to during production and human handling in vegetable growth chambers.
Publications
- Bisha, B., and B. Brehm-Stecher. 2006. "Molecular Detection of Salmonella spp. in Seed Sprouts via Flow Cytometry". Abstract P-066, in Book of Abstracts of the 106th General Meeting of the American Society for Microbiology, Orlando FL, May 21-25, 2006.
- Mendonca, A. F., O. Byelashov, L. Goodridge, and J. Lopes. 2006. Combined effectiveness of lactic acid and sodium lauryl sulfate in destroying Salmonella Enteritidis, Escherichia coli O157:H7 and Listeria monocytogenes on whole raw almonds. Abstract P5-35, In Book of Abstracts, International Association for Food Protection Annual Meeting, Calgary, Canada, Aug. 13-16, 2006.
- Mendonca, A. F., and A. Orozalieva. 2006. Combined effectiveness of hydrogen peroxide and a foodgrade surfactant for destroying Salmonella and Escherichia coli O157:H7 on whole cantaloupe. Abstract # 016-6, In Abstracts of the S-294 Regional Project Science Symposium and International Fresh Produce Association Meeting, Baltimore, MD, April 27-39, 2006.
- Mendonca, A. F., R. Morrow and L. Tuominen. 2006. Control of Human Enteric Pathogens for Safe Crop Production in the Deployable Vegetable Production System (VEGGIE). Abstract HLS 144 in Abstracts of Habitation 2006, Conference on Habitation Research and Technology, Orlando, FL, February 5 to 8, 2006.
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Progress 01/01/05 to 12/31/05
Outputs
Significant findings: Certain foodgrade chemical solutions exhibited good potential for use as sanitizers to destroy human pathogens on the surface of fresh produce such as apples, lettuce, tomatoes, and cantaloupe. Dipping whole apples and lettuce for 2.0 minutes 5% hydrogen peroxide, sodium bicarbonate buffer (pH 11.6), or a commercial sanitizer (80 ppm Tsunami 100 or 2% PRO-SAN) at 25C significantly decreased populations of Escherichia coli O157:H7. PRO-SAN was the most effective sanitizer. Also, PRO-SAN reduced numbers of E. coli or Salmonella on tomatoes by 3.0 log (1,000-fold) compared a 2.0 log (100-fold) reduction when chlorine (200 ppm) was used. Exposure of the outer rind surface of cantaloupe to sodium bicarbonate buffer solution (pH 11.0) for 10 minutes reduced numbers of Salmonella on from 200,000 to 316 colony forming units (CFU) per rind. A much greater killing effect was achieved when rinds were exposed to a combination of 5% hydrogen peroxide and 1%
citric acid for only 2.0 minutes. Irradiation (1.0 kGy) of the outer rind surface of cantaloupe and cubes of cantaloupe flesh decreased populations of Salmonella from 5,000,000 to 910 CFU/rind and from 2,000,000 to 460 per gram, respectively. Use of a higher dose (1.5 kGy) caused further destruction of the pathogen but resulted in soft texture of the cantaloupe and increased release of juices. Initial treatment of cantaloupe rind with a combination of acidified hydrogen peroxide (5% hydrogen peroxide + 1% citric acid) and sodium lauryl sulfate (1%) followed by irradiation at 0.5 or 1.0 kGy destroyed more than 100,000 CFU of salmonellae per rind.
Impacts
Contamination of fresh produce with human enteric pathogens is a major food safety concern. Information of the effectiveness of chemical solutions for destroying pathogens on the surface of fresh fruits and vegetables will offer processors a variety of alternatives to chlorine for improving the microbial safety of these products. Effective interventions for destroying pathogens on fresh produce are crucial because currently permitted levels of chlorine can not guarantee microbial safety of fresh fruits and vegetables.
Publications
- Mendonca, A.F., Romero, M.G., Orozalieva, A. and Woods, F. 2002. Survival and growth of Salmonella spp. on Freshcut Cantaloupe cubes and rind following electron beam irradiation. Abstract P102, In Book of Abstracts of the International Association for Food Protection Annual Meeting, San Diego, CA, June 30 to July 3, 2002.
- Romero, M. G., A. Orozalieva, and A. F. Mendonca, 2004. Altered resistance of Acid-adapted Escherichia coli O157:H7 to hydrogen peroxide and PRO-SAN. Abstr. P162, In Book of Abstracts, International Association for Food Protection Annual Meeting, Phoenix, AZ, Aug. 8-11, 2004.
- Orozalieva, A., and A. F. Mendonca. 2005. Inactivation of Salmonella spp. and Escherichia coli O157:H7 on cantaloupe skin using citric acid, hydrogen peroxide and a foodgrade sanitizer. Abstr. P2-42, In Book of Abstracts, International Association for Food Protection Annual Meeting, Baltimore, MD, Aug. 14-17, 2005.
- Mendonca, A. F. 2005. Bacterial infiltration and internalization in fruits and vegetables, pp. 441-462. In O. Lamikanra, S. Iman, and D. Ukuku (ed). Produce Degradation: Pathways and Prevention, CRC Press, Boca Raton, FL.
- Traynham, T. L. 2003. Destruction of Escherichia coli O157:H7 on whole apples via single and sequential application of chemical sanitizers. M.S. Thesis, Iowa State University, 2003.
- Orozalieva, A. 2005. Efficacy of selected chemicals and electron beam irradiation for destroying Escherichia coli and Salmonella on cantaloupe skin. M.S Thesis, Iowa State University, 2005.
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Progress 01/01/04 to 12/31/04
Outputs
Hydrogen peroxide (H2O2; 5%), sodium hypochlorite (500 ppm), and PRO-SANTM (1% ), a biodegradable foodgrade sanitizer, were evaluated for destroying Escherichia coli O157:H7 and Salmonella spp on whole tomatoes. Tomatoes, inoculated with a 5-strain mixture of E. coli O157:H7 or Salmonella spp, were immersed for 4 min in distilled water (control) or in each sanitizer at 23 OC. A portion of the sanitized tomatoes was rinsed for 5 s in fresh distilled water to remove residual sanitizer. Rinsed tomatoes were analyzed for survivors of each pathogen whereas sanitized, non-rinsed tomatoes were stored at 25 OC for 8 days. Survivors of pathogens were enumerated immediately after treatment and during storage of tomatoes. Initial populations of E. coli or Salmonella on tomatoes were 7.0 log10 colony forming units (CFU)/tomato. PRO-SAN consistently inactivated >3.0 log of each pathogen. Log10 reductions on tomatoes immersed in water, H2O2, hypochlorite, and PRO-SAN were 1.25,
2.0, 2.31 and 3.51 (E. coli), and 1.08, 2.47, 2.43, and 3.22 (Salmonella spp), respectively. A significant decrease in E. coli survivors occurred only on PRO-SAN-treated tomatoes at day 8 of storage (P<0.05). The use of 1% PRO-SAN at 23 OC seems to have good potential as a sanitizer for fresh produce because of its antibacterial efficacy and its biodegradable characteristic.
Impacts
Contamination of fresh produce with human enteric pathogens is a major food safety problem. This research offers processors of fresh produce, more effective alternatives to chlorine for decontaminating fruits and vegetables to be eaten raw.
Publications
- Sikinyi, T., and A. F. Mendonca. 2004. Inactivation of Escherichia coli O157:H7 and Salmonella spp. on whole tomatoes following immersion in selected chemical sanitizers. Abstract P 239, in Abstracts of the Annual Meeting of the International Association for Food Protection, Phoenix, AZ, Aug 8 to 11, 2004.
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Progress 01/01/03 to 12/31/03
Outputs
The killing effect of selected sanitizers against E. coli O157:H7 on whole apples and lettuce leaves was evaluated. Apples and lettuce were immersed for 2 min in water or in 200 ppm hypochlorite, hydrogen peroxide (H2O2, 5% wt/vol), sodium hydroxide/bicarbonate buffer (NaOH-NaHCO3; pH 11.6), Tsunami 100 (80 ppm), and Pro-San (2% wt/vol) at 25 OC. Numbers of E. coli O157:H7 on no-wash controls were 6.42 logs (per apple) and 6.36 logs (per lettuce leaf). Water alone reduced E. coli O157:H7 on apples and lettuce by 1.43 logs and 1.20 logs, respectively. Except for the hypochlorite, all sanitizers gave log reductions ranging from 2.84 to 3.27 logs (for apples) and from 2.36 to 3.08 logs (for lettuce); Pro-San (2%) was the most effective treatment. In additional studies log10 reductions of E. coli on apples washed in water, chlorine, H2O2, NaHCO3, Tsunami100, and H2O2 + lactic acid at 25 degrees C were 1.71, 1.87, 2.55, 2.47, 1.99, and 3.35, respectively. Increasing the
temperature to 55 degrees C enhanced the antimicrobial effectiveness of the sanitizers. Log10 reductions at 55 OC increased to 1.73, 1.91, 2.66, 2.56, 2.44, and 3.51 after treatment with water, chlorine, H2O2, NaHCO3, Tsunami100 (registered trademark), and H2O2 + lactic acid, respectively. PRO-SAN or H2O2 + 1.5% lactic acid at 25 degrees C or 55 degrees C is more effective than the currently used chlorine for destroying pathogens on fresh produce.
Impacts
The occurrence of pathogenic bacteria on fresh fruits and vegetables eaten raw is a major public health issue. This research offers fruit and vegetable producers simple, more effective alternatives to chlorine for decontaminating fresh produce.
Publications
- Traynham, T., A. Mendonca, B. Glatz, and M. Gleason. Inactivation of GFP-transformed Escherichia coli O157:H7 on whole apples following immersion in selected chemical sanitizers at 25 OC and 55 OC. Abstract P211, in Abstracts of the Annual Meeting of the International Association for Food Protection, New Orleans, LA, Aug 10 - 13, 2003.
- Mendonca, A. F., T. L. Traynham, B. A. Glatz, and A. Orozalieva. Killing effect of selected chemicals against Escherichia coli O157:H7 on whole apples and lettuce. In Abstracts of the 3rd Annual Meeting of the International Fresh Produce Association and S-294 Science & Technology Symposium, Tampa, FL., April 3-3, 2003.
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Progress 01/01/02 to 12/31/02
Outputs
The viability of Escherichia coli O157:H7 on whole apples was evaluated in response to a 2-minute exposure to water (control) and five different sanitizers: sodium hypochlorite (200 ppm chlorine), 5% hydrogen peroxide (H2O2), sodium bicarbonate buffer (NaHCO3 , pH 11.5), 80 ppm Tsunami100, and 1.5% H2O2 + 1.5% lactic acid. At 25 degrees C initial numbers of E. coli on apples ( 5.26 log10 CFU/apple) were reduced by 1.71, 1.87, 2.55, 2.47, 1.99, and 3.35 logs following immersion in water, chlorine, H2O2, NaHCO3, Tsunami100, and H2O2 + lactic acid, respectively. Increasing the temperature to 55 degrees C enhanced the antimicrobial effectiveness of the sanitizers. Log10 reductions at 55 OC increased to 1.73, 1.91, 2.66, 2.56, 2.44, and 3.51, respectively. The use of and1.5% H2O2 + 1.5% lactic acid at was most effective for destroying E. coli O157:H7 on whole apples. The survival and growth of salmonellae on cubes of fresh-cut cantaloupe following electron beam irradiation
were investigated. Irradiation of cubes with 1.0 and 1.5 kGy reduced initial numbers of Salmonella (2.0 x 106) to 4.6 x 102 and 1.3 x 102 CFU/g, respectively. Survivors grew rapidly on cubes held at 25 OC. At 12h viable counts on cubes irradiated at 0.0, 0.5, 1.0, and 1.5 kGy, increased to 8.5 x 109, 1.2 x 107, 2.6 x 106 and 6.0 x 105 CFU/g, respectively. Numbers of survivors on cubes did not increase during 14 days of storage at 5 degrees C. Irradiation at 1.5 kGy resulted in significant softening of cubes and increased purge. Such changes were less pronounced following treatment with 0.5 or 1.0 kGy.
Impacts
Contamination of fruits and vegetables with human pathogens such as Salmonella and E. coli O157:H7 is a major public health issue. The destruction of E. coli O157:H7 on whole apples by dipping apples in selected food grade sanitizers is a cost effective alternative to heat pasteurization that can be easily implemented by apple cider producers. Electron beam irradiation plus low temperature storage can improve the microbial safety of cantaloupe for consumers.
Publications
- Traynham TA, AF Mendonca and BA Glatz. 2002. Inactivation of Escherichia coli O157:H7 on whole apples by sequential application of a high pH sodium bicarbonate buffer and hydrogen peroxide. Abstract # 17, in Abstracts of the 2nd Annual International Fresh Produce Association and S-294 Science & Technology Symposium, Los Angeles, CA, April 11-14, 2002.
- Mendonca AF, TD Boylston and FM Woods. 2002. Survival and growth of Salmonella Stanley on fresh-cut cantaloupe following electron beam irradiation. Abstract # 18, in Abstracts of the 2nd Annual International Fresh Produce Association and S-294 Science & Technology Symposium, Los Angeles, CA, April 11-14, 2002.
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Progress 01/01/01 to 12/31/01
Outputs
The effect of irradiation on survival and growth of salmonellae on cubes of cantaloupe flesh and external rind surface was investigated. Fresh-cut cubes and rind were inoculated with a four-strain mixture of Salmonella (S. Typhimurium, S. Chester, S. Poona, and S. Stanley) to give 2.0 x 106 CFU/g and 5.0 x 106 CFU/rind, respectively. Inoculated samples in sterile plastic containers were irradiated with 0.0 (control), 0.5, and 1.0 kGy, then held at 5 OC (14 days) or 25 OC (24 hours). Initial populations of Salmonella spp on cubes and rind decreased with increasing radiation dose. Irradiation at 1.0 kGy significantly decreased viable populations on cubes and rind to 3.9 x 102 CFU/g and 9.1 x 102 CFU/rind, respectively. Growth of Salmonella survivors on cubes stored at 25 OC was rapid. At 12h viable counts on cubes irradiated at 0.0, 0.5, and 1.0 kGy, increased to 1.5 x 109, 1.7 x 107, and 2 x 106 CFU/g, respectively; viable counts on rind were 2.1 x 108, 3.2 x 106, and
1.7 x 106 CFU/rind, respectively. Final numbers of Salmonella were about 12 times greater on cubes than on rind. Numbers of survivors on cubes or rind did not increase during 14 days of storage at 5 OC.
Impacts
Contamination of fruits and vegetables with disease-causing microorganisms such as Salmonella and E. coli O157:H7 is a serious public health issue. This results of this research indicate that electron beam irradiation (1.0 kGy), followed by low temperature (5 OC) storage, has good potential for improving the microbial safety of fresh-cut cantaloupe.
Publications
- No publications reported this period
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Progress 01/01/00 to 12/31/00
Outputs
Studies were conducted to determine the effectiveness of various alkaline dip solutions for destroying foodborne pathogens on fresh produce. Samples of cantaloupe skin, inoculated with Salmonella Stanley, were washed for 2, 6, or 10 minutes in water (pH 7.0, control) or in sodium bicarbonate/sodium hydroxide buffer solutions (pH 9, 10, 11, or 12) at 37 or 45 degrees C. The external structure of control and treated Salmonella cells was observed by scanning electron microscopy. Numbers of Salmonella cells on skin were 5.30 log10 CFU/cm2 before immersion in water and buffer solutions. An estimated 3.6-log reduction was achieved by immersing skins in pH 12 buffer (45 degrees C) for 10 min. Numbers were significantly (P<0.05) reduced by about 2.5 logs on skins immersed in solutions at pH 11 (45 degrees C) for 10 min or at pH 12 (45 degrees C) for 2 or 6 min. Salmonella cells on skins exposed to pH 12 (45 degrees C) exhibited signs of rupture when observed by SEM. The use
of high pH NaHCO3-NaOH buffer solutions for decontaminating whole cantaloupe seems to have good potential for reducing microbial contamination of the fresh-cut fruit.
Impacts
The presence of disease-causing microorganisms such as Salmonella, E. coli O157:H7, and Listeria monocytogenes on fresh produce is a major public health concern. This research will provide producers with simple, effective ways for destroying pathogens on the skin surface of melons. Decontamination of the skin surface will reduce microbial contamination of the edible portion of the melons during further processing and improve the microbial safety of minimally processed melons.
Publications
- No publications reported this period
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