Progress 10/01/13 to 09/30/18
Outputs Target Audience:- Fresh produce industry - Safety-conscious consumers Changes/Problems:Changes were made to make the research more applicable to the food industry. For example, we discovered that when we inoculate pathogens on produce to study its decontamination with ozone,the size of inoculum affected the degree of decontamination. In fact, realistic inoculum that mimicked natural contamination produced the best results. What opportunities for training and professional development has the project provided?Training a grdauate student (Mustafa Yesil) who obtained his Ph. D. in 2017 How have the results been disseminated to communities of interest?Publications were shared with selected fresh produce processors What do you plan to do during the next reporting period to accomplish the goals?
Nothing Reported
Impacts What was accomplished under these goals?
- Developed new approach to treat fresh produce with ozone - Discovered a new bacteriophage that can be applied to fresh produce to control Escherichia coli O157:H7
Publications
- Type:
Journal Articles
Status:
Published
Year Published:
2017
Citation:
153. Yesil, M., Huang, E., Yang, X., and Yousef, A.E. 2017. Complete genome sequence of Escherichia phage OSYSP. Genome Announc. 5:e00880-17.
- Type:
Journal Articles
Status:
Published
Year Published:
2017
Citation:
154. Yesil, M., Kasler, D.R., Huang, E., and Yousef, A.E. 2017. Efficacy of gaseous ozone application during vacuum cooling against Escherichia coli O157:H7 on spinach leaves as influenced by bacterium population size. J. Food Prot. 80:1066-1071.
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Progress 10/01/16 to 09/30/17
Outputs Target Audience:- Fresh Produce Industry - Scientific community interested in fresh produce safety - USDA NIFA proposal reviewers Changes/Problems:
Nothing Reported
What opportunities for training and professional development has the project provided?Two students and a technician have been trained to decontaminate fresh produce. How have the results been disseminated to communities of interest?- Publications listed earlier. -Nonthermal technology workshops/symposia(May, 2017, Chicago, IL and October 2017, Connell) What do you plan to do during the next reporting period to accomplish the goals?Achieve the stated objectives and finalize the project.
Impacts What was accomplished under these goals?
1. A new bacteriophage (Escherichia phage OSYSP) has been fully characterized and its utility as a biocontrol agent has been confirmed. Detail of the genome of our phage can be found at this link:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5646388/ 2. Developing an effective method for decontamination of fresh produce by combination of bacteriophage and ozone gas: Treatment of spinach leaves with gaseous ozone and bacteriophage alone or in combination significantly (p < 0.05) reduced the viable E. coli O157:H7 populations on produce. Microbial reductions by gaseous ozone and bacteriophage only treatments were ranged from 1.8 to 3.4 log CFU/g and 1.7 to 3.4 log CFU/g, respectively. Sequential treatments of ozone followed by bacteriophage produced a synergy and reduced E. coli O157:H7 by 5.2 log CFU/g on spinach leaves. When the antimicrobial application order was reversed, additive inactivation responses were observed. Irrespective to the antibacterial application order in sequential treatments, no E. coli O157:H7 survivors were detected (p < 0.05) at lower inoculum sizes tested. The potent pathogen intervention techniques of this study could be easily integrated into conventional fresh produce processing with minimal changes as post-harvest chlorine spray and industrial chlorine-wash could be replaced with bacteriophage application, and combined with a gaseous ozone treatment during vacuum cooling.
Publications
- Type:
Journal Articles
Status:
Published
Year Published:
2017
Citation:
Yesil, M., Kasler, D.R., Huang, E., and Yousef, A.E. 2017. Efficacy of gaseous ozone application during vacuum cooling against Escherichia coli O157:H7 on spinach leaves as influenced by bacterium population size. J. Food Prot. 80:1066-1071.
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Progress 10/01/15 to 09/30/16
Outputs Target Audience:Fresh produce Industry. Consumers Changes/Problems:
Nothing Reported
What opportunities for training and professional development has the project provided?An undergrauate student has been trained and qualified to join a graduate program at the Ph. D. level How have the results been disseminated to communities of interest?Published in a scientific journal What do you plan to do during the next reporting period to accomplish the goals?Optimize the process developed in the previous phase
Impacts What was accomplished under these goals?
Developing and Optimizing Bacteriophage Treatment to Control Enterohemorrhagic Escherichia coli on Fresh Produce: Bacteriophages are potentially useful in controlling foodborne pathogens on minimally processed products since phage application is a non-destructive treatment. The purpose of this study was to evaluate the efficacy of a newly isolated environmental bacteriophage against enterohemorrhagic Escherichia coli on fresh produce, ?
Publications
- Type:
Journal Articles
Status:
Published
Year Published:
2016
Citation:
Snyder, A.B., Perry, J.J., and Yousef, A.E. 2016. Developing and optimizing bacteriophage treatment to control enterohemorrhagic Escherichia coli on fresh produce. Int. J. Food Microbiol. 236:90-97.
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Progress 10/01/14 to 09/30/15
Outputs Target Audience:Fruit and vegetable producers and processors; scientists working in food safety; consumers; extension educators. Changes/Problems:
Nothing Reported
What opportunities for training and professional development has the project provided?The project involved training a graduate student while working toward his Ph.D. degree How have the results been disseminated to communities of interest?The study has been shared during the 2015 annual meeting of the Institute of Food Technologists, held in June Chicago, IL What do you plan to do during the next reporting period to accomplish the goals?Optimize the treatments tested so far, to maximize their effectiveness against pathogens while protecting product quality
Impacts What was accomplished under these goals?
A an effective combination treatment (phage + ozone) can be used by used to decontaminate fresh produce against enterohemorrhagic E. coli Sequential application of bacteriophage and gaseous zone for the inactiviation of escherichia coli O157:H7 on fresh produce. Fresh produce related foodborne outbreaks call for innovative technologies in order to protect the safety of the consumers. These technologies also should prevent economic losses for the fresh produce industry due to contaminated produce. Chlorine is used by industry for decontamination of fresh produce. However, at the permitted levels of use, chlorine does not generate considerable microbial inactivation. Additionally, concerns have been raised due to overuse of chlorine and formation of possible carcinogenic side products of chlorinated water used to wash produce. Ozone and bacteriophage do not have the drawbacks of chlorine, and thus can serve as alternatives to this commonly used sanitizer. The studies that we conducted revealed that an isolated and characterized lytic phage and gaseous ozone treatment individually and when applied sequentially gave significantly higher inactivation of Escherichia coli O157:H7 on spinach leaves when compared to control treatments. In the first study, we investigated the efficacy of gaseous ozone for the inactivation of different contamination levels of E. coli on spinach leaves. The E. coli reductions obtained were 0.2 log CFU/g at the high, and 2.1 log CFU/g at the low inoculum level, when compared to inoculated untreated spinach leaves. Ozone treatment of leaves inoculated at 7.3 log CFU/g significantly (p<0.05) increased the inactivation of E. coli compared to the higher inoculum level. Additionally, spinach leaves were inoculated with 3.2 log CFU/g of E. coli O157:H7 and most probable number technique was employed for the detection of low level of viable cells after ozone treatment. MPN estimates of the target pathogen was <3 MPN/g (i.e., greater than a 3 log reduction). In the second study, we have studied the efficacy of spraying E. coli-specific bacteriophage on produce after harvest and subsequently treating the produce with gaseous ozone during the vacuum cooling for the inactivation of two different inoculum levels of E. coli O157:H7. At the high inoculum level, phage treatment significantly (p<0.05) reduced the target pathogen count by a 2 log CFU/g when compared to inoculated untreated control. The sequential process significantly decreased the E. coli population by a 4 log CFU/g on spinach leaves compared to untreated control. Populations of the likely pathogen contaminants on freshly harvested leaves are expected to be less than the populations used in the aforementioned experiment. When phage and gaseous ozone applied to close to realistic contamination of level of spinach, it reduced the population of pathogen to lower than the detection limit, 1 log CFU/g. The color and texture of the treated pre-bagged spinach leaves were comparable to the inoculated untreated spinach leaves. Regardless of inoculum size for the sequential application of gaseous ozone with another hurdle technology, i.e., phages, promises the enhanced efficacy of gaseous ozone against the contaminants. Due to the superior efficacy of gaseous ozone found at lower inoculum sizes, a lower ozone concentration could be used to achieve better produce quality along with microbiological quality. This studied decontamination method would be improved by using phage cocktails and would be easy to implement into existing practices of the fresh produce industry.
Publications
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Progress 10/01/13 to 09/30/14
Outputs Target Audience: 1. Fresh produce industry 2. Consumers Changes/Problems:
Nothing Reported
What opportunities for training and professional development has the project provided? A graduate student is now pusuing his Ph. D. project which covers this topic. This graduate student submitted a proposal to OARDC Seed Grants, which has been funded. How have the results been disseminated to communities of interest? The 2014 Nonthermal Technology Workshop annual meeting What do you plan to do during the next reporting period to accomplish the goals? Data supporting the hypothesis of the proposal are provided. Data on additional applications of bacteriophage (in combination with ozone) against pathogens on fresh produce
Impacts What was accomplished under these goals?
Bacteriophage are applicable for the control of foodborne pathogens, particularly relevant to the safety of produce and other minimally processed products since phage application is a non-destructive treatment. The purpose of this study was to evaluate an environmental bacteriophage isolate's ability to reduce the population of enterohemorrhagic E. coli on produce. A phage active against Escherichia coli O157:H7 EDL933 was isolated from municipal wastewater and was titered at 108 PFU/ml when replicated with the host in LB broth. Phage treatments were applied to cut green peppers and baby spinach leaves. Cut peppers were treated with UV light to eliminate background biota, then spot inoculated with E. coli O157:H7 EDL933 on cut edges and allowed to dry. Baby spinach leaves were spot inoculated with GFP labeled E. coli O157:H7 and no efforts were made to eliminate background biota. Green pepper pieces were treated with a 5 min rinse in purified phage lysate while baby spinach leaves were rinsed for only 2 min. Treated produce was stored at 4°C, with or without pre-incubation for 4 h at 25°C. A control treatment was applied in the form of a buffer rinse, which reduced E. coli populations by <1 log/g pepper and <1.5 log/g spinach. The phage treatment reduced E. coli populations on peppers and spinach by 2.6 and 3.5 log CFU/g, respectively. These findings suggest the utility of using bacteriophage to selectively control pathogens on fresh produce without incubation at ambient temperatures.
Publications
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