FOOD SAFETY MICROBIOLOGY AND FOODS FOR HEALTH

• Sponsoring Institution: National Institute of Food and Agriculture
• Project Status: TERMINATED
• Funding Source: HATCH
• Reporting Frequency: Annual
• Accession No.: 1008913
• Project No.: CA-D-FST-2106-H
• Project Start Date: Dec 18, 2015
• Project End Date: Sep 30, 2020

Project Director
Young, G.

Recipient Organization
UNIVERSITY OF CALIFORNIA, DAVIS
410 MRAK HALL
DAVIS,CA 95616-8671

Performing Department
Food Science and Technology

Non Technical Summary
Foodborne illness sickens more than 70 million people per year in the United States (Meade et al. 1999). Food safety is important to everyone and is among California's and the U. S.'s top agricultural priorities (Ananymous, 2010). Food is by definition the product of agriculture consumed by humans. It is expected that food is to be safe of harmful microorganisms and contribute to the health of the individual. While U. S. citizens enjoy having an exceptionally safe and nutritious food supply there are occasions where food becomes contaminated with pathogens (bacteria, viruses and parasites) that result in human infections. These infections, in severe cases, lead to unnecessary mortality. By completing fundamental and applied research there is a basis of scientific knowledge on which to rationally design methodologies, standards and technologies to continually improve food safety. Important to this proposal, food safety microbiology research includes agricultural practices, food processing, food affects on human health, foodborne infections and defining treatments for foodborne illness. By approaching food safety as a multifaceted challenge innovative improvements will be realized. Food safety microbiology research serves various California stakeholders throughout the safe food value chain, including farmers, food processors, food safety regulators and the general public.

Animal Health Component

0%

Research Effort Categories

Basic

40%

Applied

50%

Developmental

10%

Classification

Knowledge Area (KA)	Subject of Investigation (SOI)	Field of Science (FOS)	Percent
501	1499	1000	50%
712	4010	1100	50%

Knowledge Area
501 - New and Improved Food Processing Technologies; 712 - Protect Food from Contamination by Pathogenic Microorganisms, Parasites, and Naturally Occurring Toxins;

Subject Of Investigation
1499 - Vegetables, general/other; 4010 - Bacteria;

Field Of Science
1100 - Bacteriology; 1000 - Biochemistry and biophysics;

Keywords

food safety

eschericia coli

salmonella

vegetables

Goals / Objectives
The overall goal of the proposed project is to better investigate novel innovations for enhancing food safety that can be employed in within the agrobuisiness sector. Further, to use this knowledge to develop technologies to eliminate contamination and cross-contamination at critical points for horticulture products, such as during washing, conveying and handling. As part of this overall goal, this research will focus on the following objectives.1. Measure the rate of transfer of microbes from wash water to fresh produce as a function of fluid forces in a simulated wash water environment with and without sanitizer.2. Characterize the rate of transfer of microbes from wash water to fresh produce as a function of mixing in a simulated wash tank environment.3. Investigate the potential for developing new probes to measure oxidative stress in microbes.4. Measure the impact of organic load on the correlation between oxidative stress and microbial death in simulated wash water environment

Project Methods
Objective 1: Measure the rate of transfer of microbes from wash water to fresh produce as a function of fluid forces in a simulated wash water environment with and without sanitizer. There is a dearth of knowledge defining abiotic and biotic mechanisms that influence cross-contamination of horticulture products. To fully appreciate how bacteria survive washing regimens, we need to better define conditions that influence microbial cross-contamination. To simulate the transfer of microbes from wash water to fresh produce, potable wash water will be inoculated with known levels of selected strains of E. coli and Salmonella (log 3 to 5). Our analysis will begin with a focus on lettuce leaves but will be extended it to also include other horticulture products (leafy greens, tomato and cucubrits). Organic load, sanitizer concentrations and water to fresh produce ratio will be varied. Contaminated wash water will then be used to wash the uncontaminated lettuce leaves (once, three, five and seven times sequentially) under various flow conditions. To simulate the flow conditions of a washer, the lettuce samples will be placed on a tray in a rectangular flow channel. The length, height and width of the flow channel will be 1 m, 0.1 m and 0.5 m. The flow rate of the water in the channel will be controlled by an external water pump to create laminar (Re number less than 1400) and turbulent flow conditions (Re number > 3000) (Wang et al, 2007). After washing, the increase in microbial counts of E. coli and Salmonella strains on fresh produce will be quantified to assess the rates of transfer of microbes from wash water to fresh produce. Microbes will be enumerated on several plating media. In order to reduce the impact of background microbiota we have found it necessary to use rifampicin-resistant variants of the selected organisms (E. coli and Salmonella). Rifampicin will be incorporated into selective and non-selective agars including tryptic soy agar, CHROMAgar, and bismuth sulfite agar for E. coli O157:H7 and Salmonella isolation. The plates will be incubated at 37°C for 24 h and colonies displaying typical coloration for each media will be enumerated. When below the limit of detection, samples will be enriched using standard methods. Each experimental condition will be replicated 3 times to measure the rate of transfer of microbes under simulated conditions and statistical analysis will be used to determine significant differences among experimental data sets.Objective 2: Characterize the rate of transfer of microbes from wash water to fresh produce as a function of mixing in a simulated wash tank environment. To simulate transfer of microbes from wash water to fresh produce, the potable wash water will be inoculated with known levels of E. coli and Salmonella (log 3 to 5). Organic load and sanitizer concentrations will be varied as outlined in Table 1. The fresh produce sample (100 g of lettuce leaf) will be incubated with the contaminated wash water in a simulated wash water container with an overhead stirrer. The samples will be stirred for 5 minutes at different agitation/ mixing rates ranging from 0 to 200 rpm. The mixing rates are selected based on the conditions used for washing fresh produce in wash water tanks (Wang et al, 2007). Increase in microbial count on fresh produce after washing will be quantified using the same experimental approach described in part 1. Each experimental condition will be replicated 3 times to measure the rate of transfer of microbes under simulated conditions.Objective 3: Investigate the potential for developing new probes to measure oxidative stress in microbes. Evaluating probes: For MR spectropscopy, three redox responsive probes will be evaluated: alpha-phenyl N-tertiary-butyl nitrone (PBN) and 5,5-dimethyl-pyrroline N-oxide (DMPO) and TEMPO-H. These probes are selected because: (a) can react with a large diversity of free radicals (O-, N-, S-, and C-centered radicals) [60-63]; (b) are cell permeable, non-toxic and can rapidly penetrates across lipid bilayers (Finkelstein, 1980; Lavi et al, 2010); (c) rapid reaction with a large diversity of free radicals to form stable adducts. This is critical as free radicals are short lived species (life span for many radical species ranges from nanoseconds to microseconds). The stable adducts formed upon reaction of spin trap probes with radicals can be quantified using a portable NMR or ESR device and (d) the midpoint redox values of selected spin trap probes (e.g. TEMPO-H is 880 mV) provides sufficient dynamic range to measure oxidation potential of sanitizers (~ 700 mV) (Kulkarni et al, 2008). Thus, these probes have an excellent dynamic range to measure oxidative stress in microbes. Optimization of labeling conditions: Labeling of microbes with spin trap probes will be evaluated by varying the concentration of spin probe (100 μm to 5 mM) in aqueous phase for a fixed concentration of microbes (106 CFU/ml). The microbes will be incubated with spin probes at two different temperature conditions (room temperature and 37?C) for 10 minutes. Uptake of probes will be quantified based on MR measurements. Reaching saturation levels for a high microbial count will ensure that the concentration of spin probes is optimal for the lower count of microbes (102 to 105 CFU/ml). In our preliminary we have used spin trap probes at concentration levels of 2 mM to label E. coli 0157-H7. Sensitivity to detect oxidative stress in microbes for a diverse range of sanitizers: To demonstrate that the proposed approach can be used for a diverse class to sanitizers, spin labeled E. coli will be incubated with the selected sanitizers. The microbial concentration will range from 102 to 106 CFU/ml. Measurement Approach: To evaluate sensitivity of detecting changes in spin probes (induced by oxidative stress), changes in T1 and T2 relaxation times of water protons will be measured based on well-established pulse sequences (T2 measurement by -CPMG or Hahn Echo pulse sequences, T1 measured by saturation recovery or inversion -recovery pulse sequences). In addition to the laboratory design system, these portable or benchtop models of NMR devices are now commercially available and are routinely used for process control in diverse industries including food and pharmaceutical http://www.bruker.com/industries/food-agriculture/food-quality.html.

Progress 12/18/15 to 09/30/20

Outputs
Target Audience:Target audiences for this research include anyone connected to the food production or food value chain. This research effort addresses critical areas of that affect stakeholders throughout the agricultural community of food producers. Specific goals are to provide new methods for pathogens detection in food and to provide new technologies to mitigate microbial food safety risks. Dissemination of knowledge is achieved through a variety of outreach efforts. 1. The research has been highlighted by media organizations and newsletters; 2.) Direct meetings with individual food industry leaders have taken place; 3.) Our research team maintains an industry advisory board that meets to discuss research priorities, outcomes and co-develops new avenues of inquiry. For the general public, on site tours have been delivered to university visitors from the local community, industry groups and public open-house events. Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided?The project has served a foundation of applied research that has allowed training of three additional graduate students and two postdoctoral scientists during the past year. How have the results been disseminated to communities of interest?Activities and outputs that disseminate results from this research happen in numerous ways. The least direct outlet is through our departmental Leadership Board, which has between 20 - 25 members at a given time. The Leadership Board consists of leaders from government and industry that meet quarterly though the academic year to learn about the entire portfolio of departmental accomplishments for research and extension. My progress is conveyed to this group primarily through the communications of the Departmental Chair. https://foodscience.ucdavis.edu/people-type/leadership-board/ I have direct interactions with individual food industry leaders through my own networking interactions. I annually invite industry leaders to the UC Davis campus. I invite them to fulfill three purposes 1.) To connect with students and discuss career development in the food industry, 2.) To provide me with the opportunity to discuss with them our ongoing research activities (this directly connects to the AES Mission) and 3.) To meet with other UC Davis AES researchers to learn about their research impact on the food industry. People that I have met one on one with are listed below: Jeremy Benson, President, Benson Marketing Group Rob Twyman, President, Northern California & Reno Region, Whole Foods Market Dan Voit, President, Blentech Corporation Barb Stuckey, President and Chief Innovation Officer, Mattson Cindy Eckart, Vice President R&D/Product Innovation, Torani Chris Cuvelier (CEO) and Pete Brennan (Chief Growth Officer), Zola Fruits of the World Elizabeth Clair (National Confectionery Sales Manager) Barry Gallebaut Chocolates Andrew Brentano, (Co-founder and CEO) Tiny Farms Dan Morash* (President and CEO) California Safe Soils *Note that this contact is solely an industry contact that I communicate with to provide input on their use of food waste to produce a fertilizer for vegetable production. This contact was added to this list because the interactions are similar to those of the others listed. Previously we published together in 2016 and visit semi-annually as the company develops new agricultural uses for their products. There are other direct contacts with stakeholders have relevance to the AES Mission. As part of a large USDA NIFA multi-institutional project -- An integrated approach to eliminate cross-contamination during washing, conveying, handling, and packaging of fresh produce -- with Professor Nitin Nitin. The HATCH project is specifically aligned with this USDA-NIFA project. Dr. Nitin, on behalf of our team, has presented at industry workshops hosted by the Post-Harvest Center, led by Extension Specialist Elizabeth Mitcham in 2018 and 2019, and attended by 70 - 80 professionals. We have assembled a project-specific Industrial Advisory Board (IAB). The project board meets with us each Fall quarter for a full day and occasionally during the year to converse about "real-world" factors that impact our ability to advance new ideas and technology to impact food safety. These conversations and meetings provide excellent communication for formulating future directions and to discuss ways in which results might be translated into practical solutions that can be adopted by food producers. Members of the project IAB are listed below: Lisa Gorski (Food Safety Microbiology Group Leader) USDA-ARS Suzzane Tortorelli (Driector of Global Food Safety) Cambell's Soups Eric Wilhelmsen, ADP Consultants Melissa Ortner, (Food Safety Officer) Heinzen Manufacturing and Channelized Solutions Jim Brennan, (President) Smartwash Solutions Rich Walsh, (Staff Scientist) EcoLab Inc. Linda Harris, Extension Specialist, UC Davis Besides the USDA-NIFA funded research, I also Co-PI with Professors Nitin Nitin and Gang Sun the project Rechargeable antimicrobial and antifouling plastics for improved cleaning and sanitation of plastic bins and totes, funded by the Center Produce Safety (CPS); https://www.centerforproducesafety.org/ . This project also aligns with my HATCH project. The CPS, headed by Bonnie Hernandez, serves as a clearinghouse for industry stakeholders to specifically fund research and development projects. Projects are solicited by industrial-partners to solve industry-defined problems. The results are disseminated publically by CPS to inform industry and the public about progress on food safety issues. Our project focuses on developing novel materials that have antimicrobial activity with the goal to limit or, possibly, prevent cross-contamination events affecting fruits and vegetables throughout the value chains (farm to fork). These projects involve routine progress reports to industry stakeholders. Our group also presents at the annual CPS meeting (strongly attended by industry representatives) and also has been highlighted through other communications that reach a broad audience. Links to those communications are listed below: 1. CPS research focuses on making containers antimicrobial. Ag Web Farm Journal https://www.agweb.com/article/cps-research-focuses-on-making-containers-antimicrobial/ 2. Reducing Cross-Contamination in Fresh Produce Processing. Universities Alliance for Agricultural Science https://fedbyscience.org/stories-of-discovery/reducing-cross-contamination-in-fresh-produce-processing/ 3. New Packaging Aims to Prevent Produce Spoilage. UC Davis https://microbiome.ucdavis.edu/news/new-packaging-aims-prevent-produce-spoilage/ 4. Plastic to Limit Cross-Contamination in Produce Bins. The California Aggie https://theaggie.org/2019/02/05/plastic-to-limit-cross-contamination-in-produce-bins/ I also work in partnership with UC Cooperative Extension Specialist Elizabeth Mitcham, who leads the UC Davis Horticulture Innovation Lab. This is a USAID funded program supporting the Safe Vegetable Value Chain Project in Cambodia. The project has both research and extension components aimed at improving food safety from the farm to the fork. Here on campus, this work is highlighted by the Horticulture Innovation Lab to inform local stakeholders about universal solutions to global challenges. For example, my team's field-work resulted in greater implementation of net houses that reduces the use of chemical pesticides and increased hygiene --- both of which improve levels of food safety for fresh vegetables. The net houses are among the technology included in the demonstration site on-campus near the Horticulture Innovation Lab, which hosts public events reaching local Californians. I recognize this outreach may not easily reveal how it reaches local communities but, in fact, the knowledge has been disseminated by DANR and UC Davis through alternative outlets, which I have listed below: 1. Building trust in food systems - here and in Cambodia. Website, 2017, UC Division of Agriculture and Natural Resources. https://ucanr.edu/blogs/blogcore/postdetail.cfm?postnum=23237&email=yes/ 2. Building trust in food systems - here and in Cambodia. Website, 2017, University of California Agriculture and Natural Resources Master Gardeners of Glenn County. https://ucanr.edu/sites/glennmg/?blogtag=Horticulture Innovation Lab&blogasset=36860/ 3. Building trust and resilience in a safe vegetable value chain in Cambodia. Video, 2017, USAID Horticulture Innovation Lab at UC Davis. https://www.youtube.com/watch?time_continue=1&v=M9QeU2O-8cU/ 4. How Agricultural Innovations Help Feed the Future In Cambodia, Video, 2019, University of California, Davis and College of Agriculture and Environmental Sciences. https://www.youtube.com/watch?time_continue=38&v=0NvDuKfRFGQ/ What do you plan to do during the next reporting period to accomplish the goals? Nothing Reported

Impacts
What was accomplished under these goals? The research and outreach activities impact stakeholders throughout the agricultural and food value chain. The goal is to research and develop innovative approaches for disrupting the problems that arise which lead to contamination of the food supply. Food safety is important to everyone and is among California's and the U. S.'s top agricultural priorities. Food is, by definition, the product of agriculture consumed by humans. It is expected that food is to be safe of harmful microorganisms and contribute to the health of the individual. This project addressed current critical issues impacting food production. In particular, we defined and developed solutions that eliminate contamination of produce (fruit and vegetables) that commonly are consumed "fresh" by people. The research addressed the following objectives: 1. Measure the rate of transfer of microbes from wash water to fresh produce as a function of fluid forces in a simulated wash water environment with and without sanitizer. 2. Characterize the rate of transfer of microbes from wash water to fresh produce as a function of mixing in a simulated wash tank environment. 3. Investigate the potential for developing new probes to measure oxidative stress in microbes. 4. Measure the impact of organic load on the correlation between oxidative stress and microbial death in simulated wash water environment The annual HATCH progress reports listed the relevant publications related to these objectives. We have made progress on each objective and continue moving forward with our project. As an added benefit, this work is further supported by a USDA-NIFA award and an award from the Center for Produce Safety.

Publications

• Type: Journal Articles Status: Published Year Published: 2020 Citation: Yang, X., Wisuthiphaet, N., Young, G.M. and Nitin, N., 2020. Rapid detection of Escherichia coli using bacteriophage-induced lysis and image analysis. PloS one, 15(6), p.e0233853.
• Type: Journal Articles Status: Published Year Published: 2020 Citation: Yi, J., Huang, K., Young, G. M., & Nitin, N. Quantitative analysis and influences of contact dynamics on bacterial cross-contamination from contaminated fresh produce. Journal of Food Engineering, 270, 109771.
• Type: Conference Papers and Presentations Status: Published Year Published: 2020 Citation: Wisuthiphaet, N., Yang, X., Young, G. and Nitin, N., 2020. Rapid Detection of Pathogenic Bacteria Using Engineered Bacteriophage. IAFP 2020.
• Type: Journal Articles Status: Published Year Published: 2020 Citation: Yi, J., Huang, K., Young, G.M. and Nitin, N., 2020. Quantitative analysis and influences of contact dynamics on bacterial cross-contamination from contaminated fresh produce. Journal of Food Engineering, 270, p.109771.
• Type: Journal Articles Status: Published Year Published: 2020 Citation: Liu, D., Zhang, Z., Liao, N., Zou, S., Tang, H., Tian, P., Young, G.M., Wu, Q. and Wang, D., 2020. Culturable bacteria resident on lettuce might contribute to accumulation of human noroviruses. International Journal of Food Microbiology, 317, p.108492.
• Type: Journal Articles Status: Published Year Published: 2020 Citation: LeGrand, K., Borarin, B. and Young, G.M., 2020. Tradition and Fermentation Science of prohok, an ethnic fermented fish product of Cambodia. Journal of Ethnic Foods, 7, pp.1-19.

Progress 10/01/18 to 09/30/19

Outputs
Target Audience:Target audiences for this research include anyone connected to the food production or food value chain. This research effort addresses critical areas of that affect stakeholders throughout the agricultural community of food producers. Specific goals are to provide new methods for pathogens detection in food and to provide new technologies to mitigate microbial food safety risks. Dissemination of knowledge is achieved through a variety of outreach efforts. 1. The research has been highlighted by media organizations and newsletters; 2.) Direct meetings with individual food industry leaders have taken place; 3.) Our research team maintains an industry advisory board that meets to discuss research priorities, outcomes and co-develops new avenues of inquiry. For the general public, on site tours have been delivered to university visitors from the local community, industry groups and public open-house events. Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided?The project has served a foundation of applied research that has allowed training of three additional graduate students and two postdoctoral scientists during the past year. How have the results been disseminated to communities of interest?Outreach from this research has taken place throughout the year. I have met individually with stakeholders and industry leaders. The work on food safety and sanitation additionally has an industry advisor board guiding priorities and giving feedback. The board includes professionals from the food industry, the USDA Western Regional Research Center and California Agriculture and Natural Resources Cooperative Extension. Below is a list of some contacts from the past year: Jeremy Benson, President, Benson Marketing Group Rob Twyman, President, Northern California & Reno Region, Whole Foods Market Dan Voit, President, Blentech Corporation Barb Stuckey, President and Chief Innovation Officer, Mattson Cindy Eckart, Vice President R&D/Product Innovation, Torani Chris Cuvelier (CEO) and Pete Brennan (Chief Growth Officer), Zola Fruits of the World Elizabeth Clair (National Confectionery Sales Manager) Barry Gallebaut Chocolates Lisa Goraski (Food Safety Microbiology Group Leader) USDA-ARS Suzzane Tortorelli (Driector of Global Food Safety) Cambell's Soups Dan Morash (President and CEO) California Safe Soils Andrew Brentano, (Co-founder and CEO) Tiny Farms Eric Wilhelmsen, ADP Consultant Melissa Ortner, (Food Safety Officer) Heinzen Manufacturing and Channelized Solutions Jim Brennan, (President) Smartwash Solutions Rich Walsh, (Staff Scientist) EcoLab Inc. What do you plan to do during the next reporting period to accomplish the goals? Nothing Reported

Impacts
What was accomplished under these goals? Two studies were completed during the past year. One study investigated a new method for detection of bacterial contamination of food. Detection of bacteria in food products and production facilities is a crucial strategy supporting food safety assessments. Bacteriophages were investigated as a tool for bacterial detection due to their ability to infect specific strains of host bacteria. This appoach provided improved sensitivity, specificity, and rapidity of bacterial detection. The results of this investigation revealed this novel method provides a real opportunity for implementing a more rapid and accurate detection of pathogens impacting food safety, including E. coli, Salmonella and Listeria. The entire study has been published as listed in other sections of this summary. Another study addressed cross-contamination of fresh produce during postharvest processing, which is a significant risk factor that can lead to foodborne outbreaks. The aim of this study was to simulate cross-contamination from a contaminated lettuce to non-contaminated leaves/abiotic surfaces (glass, polyethylene), quantify the bacterial transfer efficiency to determine the influences of contact time, number of repeated contacts, and applied contact force, and evaluate the influences of surface hydrophobicity and bacterial species. The results demonstrated that bacterial transfer between leaves was instantaneous and bi-directional. These results provided insights that have practical implications to food industry by demonstrating the dynamics of pathogens transfer to food. This type of information is critical to developing approaches that mitigate food safety risks. The entire study has been published as listed in other sections of this summary.

Publications

• Type: Journal Articles Status: Published Year Published: 2019 Citation: Wisuthiphaet, N., Yang, X., Young, G. M., & Nitin, N. Rapid detection of Escherichia coli in beverages using genetically engineered bacteriophage T7. AMB Express, 9(55).
• Type: Journal Articles Status: Accepted Year Published: 2020 Citation: Yi, J., Huang, K., Young, G. M., & Nitin, N. Quantitative analysis and influences of contact dynamics on bacterial cross-contamination from contaminated fresh produce. Journal of Food Engineering, 270, 109771.
• Type: Conference Papers and Presentations Status: Published Year Published: 2019 Citation: Plastic to Limit Cross-Contamination in Produce Bins, Newspaper Article, 2019, The California Aggie. https://theaggie.org/2019/02/05/plastic-to-limit-cross-contamination-in-produce-bins/
• Type: Conference Papers and Presentations Status: Published Year Published: 2019 Citation: Reducing Cross-Contamination in Fresh Produce Processing, Other, 2019, Universities Alliance for Agricultural Science. https://fedbyscience.org/stories-of-discovery/reducing-cross-contamination-in-fresh-produce-processing
• Type: Conference Papers and Presentations Status: Published Year Published: 2019 Citation: Jiyoon Yi, Kang Huang, Glenn Young, Yue Ma, Gang Sun and Nitin Nitin. A Novel Antimicrobial Film for Preventing Cross-Contamination of Fresh Produce. Annual Meeting of the International Association of Food Protection, Louisville, Kentucky, July 21 - 24, 2019

Progress 10/01/17 to 09/30/18

Outputs
Target Audience:Food safety is a problem for the entire food value chain extending from the farm to the consumer. This critical area of agriculture research solved problems that affect stakeholders throughout the agricultural community of food producers and citizens of California. Dissemination of knowledge beyond the scientific audience occurs through multiple venues: 1. Publication of research overviews in the departmental quarterly newsletter and media organizations; 2.) Through site tours of the research laboratory and the facilities of the Food Science and Technology Department; 3.) A research program overview to members of the public that visit the university; and 4.) Direct meetings with food industry leaders. On site tours have been delivered to university students, student's parent, international visitors, casual visitors to the university (members of the public) and stakeholders (representing industrial sectors related to food science). Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided?The project has served a foundation of applied research that has allowed training of three additional graduate students and five postdoctoral scientists during the past year. It has also been an opportunity to communicate our results to leaders of the food industry including the following: Bonnie Fernandez-Fenaroli, Executive Director, Center for Produce Safety Rob Twyman, President, Northern California & Reno Region, Whole Foods Market Dan Voit, President, Blentech Corporation Paul Coletta, CEO, Urban Remedy Chris Cuvelier (CEO) and Pete Brennan (Chief Growth Officer), Zola Fruits of the World Lisa Goraski (Food Safety Microbiology Group Leader) USDA-ARS Suzzane Tortorelli (Driector of Global Food Safety) Cambell's Soups Dan Morash (President and CEO) California Safe Soils How have the results been disseminated to communities of interest?Outreach from this research continues to take taken place through the involvement of industry professionals. The work on food safety and sanitation has a industry advisor board composed of professionals from the food industry, the USDA Western Regional Research Center and California Agriculture and Natural Resources Cooperative Extension. A few of the direct contacts are listed below: Jeremy Benson, President, Benson Marketing Group Rob Twyman, President, Northern California & Reno Region, Whole Foods Market Dan Voit, President, Blentech Corporation Barb Stuckey, President and Chief Innovation Officer, Mattson Cindy Eckart, Vice President R&D/Product Innovation, Torani Paul Coletta, CEO, Urban Remedy Chris Cuvelier (CEO) and Pete Brennan (Chief Growth Officer), Zola Fruits of the World Elizabeth Clair (National Confectionery Sales Manager) Barry Gallebaut Chocolates Lisa Goraski (Food Safety Microbiology Group Leader) USDA-ARS Suzzane Tortorelli (Driector of Global Food Safety) Cambell's Soups Dan Morash (President and CEO) California Safe Soils What do you plan to do during the next reporting period to accomplish the goals? Nothing Reported

Impacts
What was accomplished under these goals? The research completed during the reporting period related to two aspects of our broad goals to impact food safety and healthy foods. With regards to food safety, one project completed was to give young entreprenuers the opportunity to work in small groups and conduct evidence?based research with farmers, apply food science principles, and develop Success Skills, including the ability to think critically and communicate clearly. The result was a collection of new agriculture product ideas that could potentially improve food safety of minimally processed foods and diversify agricultural products from plant-based foods. In another project, Shared Interest Savings Groups (SISGs) were initially designed to help low-income farming communities learn to (a) amass lump sums of capital for investments in agriculture, and once operational also served as an organizing platform to (b) collectively identify problems and test solutions, and (c) provide funding for early scaling of appropriate agricultural technologies. The results have provided evidence for an innovative model for effectively mitigating multiple constraints that typically hinder agricultural advancements in setting where food value chains constraint due to poor access to new knowledge and inadequate access to new technologies. With regards to health foods, we examined the potential for developing new fermented foods by the exploring the potential for using alternative grains to produce probiotic sour dough breads. This study enhanced the corpus of existing knowledge on the microbial diversity of gluten-free sourdough and provided a basis for the possible application of Pediococcus spp. and Weisella spp. as a starter culture(s) in fermented products with probiotic properties.

Publications

• Type: Journal Articles Status: Published Year Published: 2017 Citation: LeGrand, K., Yamashita, L., Trexler, C.J., Vu, T.L.A. and Young, G.M., Developing Food Science Core Competencies in Vietnam: The Role of Experience and Problem Solving in an Industry-Based Undergraduate Research Course. Journal of Food Science Education, 16(4), pp.118-130.
• Type: Journal Articles Status: Published Year Published: 2018 Citation: Adepehin, J.O., Enujiugha, V.N., Badejo, A.A., Young, G.M., Odeny, D.A. and Wu, F., 2018. Bacterial ecology and rheological parameters of multigrain gluten-free sourdoughs. LWT.
• Type: Journal Articles Status: Published Year Published: 2018 Citation: LeGrand, K., Borarin, B., Thort, C., Miller, G.D., Thong, K., Trexler, C. and Young, G.M., 2018. Leveraging Shared Interests to Advance Sustainable Food Safety Systems in Cambodia. Journal of Rural and Community Development, 13(3).

Progress 10/01/16 to 09/30/17

Outputs
Target Audience:Food safety is a problem for the entire food value chain extending from the farm to the consumer. This critical area of agriculture research solved problems that affect stakeholders throughout the agricultural community of food producers and citizens of California. Dissemination of knowledge beyond the scientific audience occurs through multiple venues: 1. Publication of research overviews in the departmental quarterly newsletter and media organizations; 2.) Through site tours of the research laboratory and the facilities of the Food Science and Technology Department; 3.) A research program overview to members of the public that visit the university; and 4.) Direct meetings with food industry leaders. On site tours have been delivered to university students, student's parent, international visitors, casual visitors to the university (members of the public) and stakeholders (representing industrial sectors related to food science). I additionally organize a class, FST190, to bring food industry leaders to campus to interact with faculty and students. Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided?The project has served a foundation of applied research that has allowed training of four graduate student and three postdoctoral scientists during the past year. It has also been an opportunity to communicate our results to leaders of the food industry including the following: Jeremy Benson, President, Benson Marketing Group Rob Twyman, President, Northern California & Reno Region, Whole Foods Market Dan Voit, President, Blentech Corporation Barb Stuckey, President and Chief Innovation Officer, Mattson Cindy Eckart, Vice President R&D/Product Innovation, Torani?Paul Coletta, CEO, Urban Remedy Chris Cuvelier (CEO) and Pete Brennan (Chief Growth Officer), Zola Fruits of the World Elizabeth Clair (National Confectionery Sales Manager) Barry Gallebaut Chocolates Lisa Goraski (Food Safety Microbiology Group Leader) USDA-ARS Suzzane Tortorelli (Driector of Global Food Safety) Cambell's Soups Dan Morash (President and CEO) California Safe Soils How have the results been disseminated to communities of interest?Outreach from this research has taken place through the involvement of industry professionals. The project for food sanitation has a industry advisor board composed of professionals from the food industry, the USDA Western Regional Research Center and California Agriculture and Natural Resources Cooperative Extension. A few of the direct contects are listed below: Jeremy Benson, President, Benson Marketing Group Rob Twyman, President, Northern California & Reno Region, Whole Foods Market Dan Voit, President, Blentech Corporation Barb Stuckey, President and Chief Innovation Officer, Mattson Cindy Eckart, Vice President R&D/Product Innovation, Torani?Paul Coletta, CEO, Urban Remedy Chris Cuvelier (CEO) and Pete Brennan (Chief Growth Officer), Zola Fruits of the World Elizabeth Clair (National Confectionery Sales Manager) Barry Gallebaut Chocolates Lisa Goraski (Food Safety Microbiology Group Leader) USDA-ARS Suzzane Tortorelli (Driector of Global Food Safety) Cambell's Soups Dan Morash (President and CEO) California Safe Soils What do you plan to do during the next reporting period to accomplish the goals? Nothing Reported

Impacts
What was accomplished under these goals? This project continued to explore the scientific basis for effective killing of microbes by santiation procudures commonly used in the food industry. To ensure food safety and minimize excessive use of sanitizers and water during sanitation, it is critical to develop a rapid method to assess sanitation efficacy. In one study, the potential for employing oxidative stress, membrane damage and glucose uptake measurements to assess the antimicrobial efficacy of NaOCl (0-70.4 ppm) and H2O2 (0-1.6% v/v) toward Escherichia coli O157:H7. The relative amount of intracellular reactive oxygen species (ROS) was measured using Aminophenyl fluorescein (APF) and 2′,7′- dichlorodihydrofluorescein diacetate (H2DCFDA) for cells treated with NaOCl and H2O2 respectively. Results from these ROS sensitive probes revealed a limited correlation between these oxidative stress measurements and inactivation of bacteria measured using the plate counting method. In another study, the focus was to identify biomarkers that can provide direct assessment of oxidative damage in bacteria upon exposure to sanitizers in the presence of fresh produce and correlation of these oxidative biomarkers with logarithmic inactivation of bacteria. Two endogenous bacterial biomarkers, protein carbonylation and thiol oxidation, were evaluated for assessing oxidative damage in Escherichia coli O157:H7 and Listeria innocua during sanitation of pre-cut lettuce leaves with NaOCl or H2O2. Results show that NaOCl treatment was more effective than H2O2 for oxidation of both the intracellular thiols and protein carbonylation in the selected strains. Collectively, this information is being used to advise the food industry on best practices and to improve current applications of sanitizers. In a separate study, we have been investigating the normal flora common to food. This particular study focused on microbes found in cocco bean. Using an in solico approach we defined the flora of a typical bean fermentation. Yet another study defined the role of a key regulatory protein, CsrA, in controlling expression of genes involved in the ability of Yersinia entrocolitica causing foodborn illness. This new knowledge help provide science-based information to explain why certain foodborn bacteria cause gastroenteritis in humans.

Publications

• Type: Journal Articles Status: Published Year Published: 2017 Citation: Cossu, A., Le, P., Young, G.M. and Nitin, N., 2017. Assessment of sanitation efficacy against Escherichia coli O157: H7 by rapid measurement of intracellular oxidative stress, membrane damage or glucose active uptake. Food Control, 71, pp.293-300.
• Type: Journal Articles Status: Published Year Published: 2017 Citation: Cossu, A., Dou, F., Young, G.M. and Nitin, N., 2017. Biomarkers of oxidative damage in bacteria for the assessment of sanitation efficacy in lettuce wash water. Applied microbiology and biotechnology, 101(13), pp.5365-5375.
• Type: Journal Articles Status: Published Year Published: 2017 Citation: Ozturk, G. and Young, G.M., 2017. Food evolution: the impact of society and science on the fermentation of cocoa beans. Comprehensive Reviews in Food Science and Food Safety, 16(3), pp.431-455.
• Type: Journal Articles Status: Published Year Published: 2017 Citation: Ozturk, G., LeGrand, K., Zheng, Y. and Young, G.M., 2017. Yersinia enterocolitica CsrA regulates expression of the Ysa and Ysc type 3 secretion system in unique ways. FEMS microbiology letters, 364(20).

Progress 12/18/15 to 09/30/16

Outputs
Target Audience:Food safety is a problem for the entire food value chain extending from the farm to the consumer. This critical area of agriculture research solved problems that affect stakeholders throughout the agricultural community of food producers and for citizens of California. Dissemination of knowledge beyond the scientific audience occurs through multiple venues: 1. Publication of research overviews in the departmental quarterly newsletter and media organizations; 2.) Through site tours of the research laboratory and the facilities of the Food Science and Technology Department; 3.) A research program overview to members of the public that visit the university; and 4.) Direct meetings with food industry leaders. On site tours have been delivered to university students, student's parent, international visitors, casual visitors to the university (members of the public) and stakeholders (representing industrial sectors related to food science). I additionally organize a class, FST190, to bring food industry leaders to campus to interact with faculty and students. Changes/Problems:During this reporting period, there were no changes to the project. However, there was the additional research activity to examine technology for converting food waste to safe organic soils amendments. What opportunities for training and professional development has the project provided?During the reporting period, this project provided training to four Ph.D. students, two postdocs, one professors and one cooperative extension specialist and one industry professional. The training took place during the execution of research and through group workshops. How have the results been disseminated to communities of interest?Outreach from this research has taken place through the involvement of industry professionals. The project for food sanitation has a industry advisor board composed of professionals from the food industry, the USDA Western Regional Research Center and California Agriculture and Natural Resources Cooperative Extension. What do you plan to do during the next reporting period to accomplish the goals? Nothing Reported

Impacts
What was accomplished under these goals? A direct accomplishment that fulfills an objective of this project m teams success in providing science-based development of technologies for understanding and improving the effectiveness of vegetable sanitation. Toward this goal we have had progressed toward defining and developing approaches for rapid measurement of intracellular oxidative stress, membrane damage or glucose active uptake. Specifically, This study examines the potential for employing oxidative stress, membrane damage and glucose uptake measurements to assess the antimicrobial efficacy of NaOCl (0-70.4 ppm) and H2O2 (0-1.6% v/v) toward Escherichia coli O157:H7. The relative amount of intracellular reactive oxygen species (ROS) was measured using Aminophenyl fluorescein (APF) and 2′,7′- dichlorodihydrofluorescein diacetate (H2DCFDA) for cells treated with NaOCl and H2O2 respectively. Results from these ROS sensitive probes revealed a limited correlation between these oxidative stress measurements and inactivation of bacteria measured using the plate counting method. Sanitation experiments, conducted with contaminated pre-cut lettuce leaves in water, were also carried out. Measurement of the bacterial membrane integrity was assessed using the membrane permeable probe propidium iodide (PI) and by evaluating effects on active transport by the glucose transport system using 2-(N-(7-Nitrobenz-2-oxa-1,3-diazol-4-yl)Amino)-2-Deoxyglucose (2-NBDG). The results demonstrate that the relative increase in membrane permeability using PI correlated with NaOCl, but did not correlate with H2O2 induced reduction of bacterial survival quantified by the plate counting method. In contrast to the other approaches, monitoring the loss of glucose transport system function by measuring the uptake of 2-NBDG displayed strong correlation with the reduction of bacterial survival for both NaOCl and H2O2 treatment. Overall, the study demonstrated potential of glucose uptake measurements with 2-NBDG to serve as surrogate method for the traditional plate counting, which is the current gold standard, to provide a faster analysis of sanitation processes. During this reporting period, I also conducted other related mission-based research not described in the project description. The goal of the research was to facilitate the development of a technology to convert food waste to organic soil amendments that can be use for food crop production. The value of this study was that it provided necessary validation of a technology to make beneficial use of the enormous amount of food waste. Ultimately, the study was successful in providing science-based information used by the California Department of Agriculture to approve and certify the new technology. Certification of the technology has allowed to the local company, California Safe Soil, to further expand to a facility that now has the capacity of handling up to 32,000 tons/year.

Publications

• Type: Journal Articles Status: Published Year Published: 2016 Citation: Cossu, A., Le, P., Young, G. M., & Nitin, N. (2017). Assessment of sanitation efficacy against Escherichia coli O157: H7 by rapid measurement of intracellular oxidative stress, membrane damage or glucose active uptake. Food Control, 71, 293-300.
• Type: Journal Articles Status: Accepted Year Published: 2016 Citation: Pandey, P., M. Lejeune, S. Biswas, D. Morash, B. Weimer, and G. M. Young. A new method for converting foodwaste into pathogen free soil amendment for enhancing agricultural sustainability. Journal of Cleaner Production, 112: 205-213.
• Type: Journal Articles Status: Published Year Published: 2016 Citation: Kamdar K, Khakpour S, Chen J, Leone V, Brulc J, Mangatu T, Antonopoulos DA, Chang EB, Kahn SA, Kirschner BS, Young, G.M., and DePaolo, W. Genetic and Metabolic Signals during Acute Enteric Bacterial Infection Alter the Microbiota and Drive Progression to Chronic Inflammatory Disease. Cell Host & Microbe, 19(1): 21-31.