Speakers – June 2, 2022 – Concurrent 3A

Food Safety on Fresh Produce

Dr. Keith Warriner, Professor, Department of Food Science – University of Guelph

Dr. Warriner is currently a Professor within the Department of Food Science at University of Guelph, Canada. Dr. Warriner received his BSc in Food Science from the University of Nottingham, UK and PhD in Microbial Physiology from the University College of Wales Aberystwyth, UK. He later went on to work on biosensors within the University of Manchester, UK and subsequently returned to the University of Nottingham to become a Research Fellow in Food Microbiology. He joined the Faculty of the University of Guelph in 2002.

During the last twenty five years in the field of microbiology and food safety research, Dr. Warriner has published more than 200 papers, book chapters, patents, and conference abstracts. His research interests are focused on enhancing food safety within meat processing, fresh cut sectors and more recently, in the area of marijuana edibles. To this end, his research team have advanced knowledge in the area of emerging pathogens, intervention technologies and development of biosensor devices to detection of foodborne hazards. His research in UV is developing novel decontamination methods based on gas phase hydroxyl-radicals for treating food surfaces and more recently N95 masks along with other personal protective equipment. He was awarded the Ontario Innovation of the Year award in 2017, OCE Mind to Market award in 2018, IAFP Food Safety Innovation award in 2019 and University of Guelph Innovation award in 2020. He is frequently contacted by the media to provide commentary on food safety issues and is the past President of the Ontario Food Protection Association. He is currently the Chair of the University of Guelph Biosafety committee, Director of the OMAFRA HQP Scholarship program and Associate Editor for several journals. Dr Warriner has visited Beijing, Zhengzhou, Dalian and Guangzhou for information exchange visits. He has held the position of Graduate Coordinator within the Department of Food Science and Director of the Food Safety and Quality program.


Fresh Produce Safety: The Need for Post-Harvest Interventions

To date, food safety interventions have focused on pre-harvest measures and testing to stop pathogens being introduced into the fresh produce chain. However, due the environmental distribution and endemic nature of human pathogens such control can be challenging. In addition, testing programs typically miss pathogens due to sporadic occurrence of the target that can be present below the limit of detection. Consequently, there is interest in re-visiting post-harvest intervention methods to enhance the microbiological safety of fresh produce. Previously washing fresh produce in sanitizers was viewed as a control step although it has subsequently found to lead to cross-contamination between batches if not controlled. Consequently, there is a need for innovative post-harvest approaches to decontaminate fresh produce to complement pre-harvest approaches. The presentation will provide an overview of our understanding of sources of contamination, relevant pathogens and current limitations of post-harvest washing.


Dr. Kevin M. Keener, Professor of Engineering, School of Engineering – University of Guelph

Prof. Kevin Keener is the University of Guelph’s first Barrett Family Foundation Chair in Sustainable Food Engineering. Prof. Keener joined the University of Guelph in 2019. Previously, he was a professor and the director of the Iowa State University Center for Crops Utilization Research and BioCentury Research Farm where he led a 12-member staff team providing assistance on over 100 industry, government, faculty, staff, and student projects each year to develop sustainable technologies and processes at pilot and small industrial scale for food, feed, biochemicals and bioplastics industries. He earned bachelor’s and master’s degrees in agricultural engineering from Ohio State University and a doctorate in food processing engineering from Purdue University in 1996. He has visiting professor appointments at South China University of Technology, University College Dublin (Ireland), and Dublin Institute of Technology (Ireland). He also previously served as a 2014 Distinguished Fulbright Professor at Russian State Agrarian University – Moscow Timiryazev Agricultural Academy. He is a Fellow of the American Society of Agricultural and Biological Engineers (ASABE) and the Institute of Food Technologists.

Dr. Keener has authored more than 170 publications, including 90 peer-reviewed journal papers, 13 book chapters, and 12 patents. He has also delivered over 100 workshops on food safety, food quality, food manufacturing, food export, food technology, food regulations, and environmental sustainability to over 2500 food manufacturers, government inspectors, and food entrepreneurs around the world.

Keener’s research focuses on improving safety processes and practices to reduce food waste, increase the use of food and fibre, and ensure sustainable food manufacturing processes. He develops novel food technologies that can enhance sustainable food systems and ensure the global transport of safe, nutritious high-quality food that benefits consumers, food manufacturers and government agencies. He has invented a number of novel technologies including controlled dynamic radiant frying, variable heat flux heat exchanger, high voltage atmospheric cold plasma, and others. Atmospheric cold plasma technology is an emerging, green process that can aid food manufacturers in increasing processing efficiency, reducing overall food waste, and reducing greenhouse gas emissions. It can be applied as a surface decontamination technology for foodstuffs and food packaging material at room temperature with minimal energy input.


Application of Gas Plasma for Decontaminating Fresh Produce

Fresh produce is harvested from a field and minimally processed prior to reaching the consumer. Because of the open production environment in the field, pathogens such as Salmonella enterica and E. coli O157:H7 have been found in these products because of field contamination or processing plant contamination. There is a need to develop alternative processes which can further reduce this food safety risk while maintaining the quality in fresh produce. Cold plasma is a promising technology that has been shown successful in reducing both pathogens and pesticide residues in fresh produce. This presentation will explore high voltage atmospheric cold plasma’s (HVACP) potential to reduce and possibly eliminate these risks. Several examples will be provided including strawberries and spinach along with others. Presentation highlights will include operational costs, scale-up challenges, and the many potential commercial opportunities for this technology.   

Dr. Tatiana Koutchma, Research Scientist, Agriculture and Agri-Food Canada – Guelph Research and Development Centre

Dr. Tatiana Koutchma is a Research Scientist at the Agriculture and Agri-Food Canada, Guelph Research and Development Centre where she leads research in novel processing and food safety engineering and serves as a Graduate Faculty at University of Guelph.  Tatiana’s activity focuses on application of novel processing technologies to enhance microbial safety and functionality of foods and feed, addresses issues of chemical safety including regulatory approvals, validation and technology transfer.  Tatiana initiates, directs and performs integrated fundamental and applied research, interacts extensively with international government agencies and collaborates with industry and academia partners.

Tatiana is an active promoter of novel food processing and science-based regulations to professional community.  She is an Associate Editor of the Compehensive Reviews in Food Science and Food Safety, Journal of Food Process Engineering, Food Science and Technology International, Also, Tatiana served on the Board of Directors of Ontario Food Protection Association (OFPA), National Advisory Committee of Food Processing Council HR of Canada, Process Innovation Advisory Board of PepsiCo; Global Harmonization Initiative as Canadian Ambassador and a Leader of Emerging Technologies Group.  She is a co-founder and co-chair of UV for Food Working Group of International UV Association (IUVA). Tatiana is a past Chair of Nonthermal Processing Division of Institute of Food Technologies (IFT) and a lead in food engineering track of Annual Meeting Scientific Program Advisory Panel (AMSPAP).


UV Light Emitting Diodes to Improve Safety and Quality of Foods and Beverages

Fast advancements in ultraviolet light-emitting diodes (UV-LEDs) technology  have allowed for their successful integration into UV food systems including point-in-place disinfection devices,  conveyor units designed for fresh produce and packaged foods, and continuous flow units for water and beverages.  A number of studies was conducted to measure efficacy of UV LEDs at multiple wavelengths including 255, 265 and 275 nm for pathogens inactivation and increasing shelf-life of fresh produce and beverages. The bacterial inactivation, destruction of vitamin C (ascorbic acid)  and antioxidants was measured on products surfaces and beverages using LEDS exposure at above  wavelengths. UV absorbed fluence was determined for achieving 5-log reduction of pathogens. The presentation will focus on overviewing the current status of UV LEDs for food and beverages  applications and present critical engineering factors to consider for development and validation of UV LEDs systems for foods. Also, the results of recent studies of LEDS for leafy greens, apples and cold pressed beverages will be presented. Better understanding of bacterial and nutrients destruction at multiple wavelengths will allow to optimize UVC treatment with improved safety and achieve higher retention of quality and nutritional content. 

Dr. Mahdiyeh Hasani, Post-doctoral Research Fellow – University of Guelph

Mahdiyeh Hasani obtained her BSc and MSc in Food Science at the University of Tabriz and Ph.D. in Food Process Engineering from the Gorgan University of Agricultural Science & Natural Resources. She has a broad interest in food process engineering, then has included fermentation, processing and, more recently, novel surface decontamination technologies. Dr. Hasani holds the position of Post-doctoral Research Fellow within the Department of the Food Science University of Guelph. Research highlights include developing a surface decontamination method based on generating hydroxyl radicals. The technology has been commercialized for decontaminating fresh produce and, more recently, N95 masks along with other personal protective equipment. Dr. Hasani’s research excellence has been recognized by being awarded the University of Guelph Innovation of the Year in 2020 and Mitacs & NRC-IRAP Award for Commercialization 2020. She has published her work in highly rated peer-review journals and presented at conferences. Dr. Hasani undertakes consultation in the industry and sits on the University Research Committee.


Gas Phase-Hydroxyl-Radical Process for Decontaminating and Extending the Shelf-life of Fresh Produce

Hydroxyl-radicals are generated by the UV-C degradation of hydrogen peroxide and/or ozone. The principle has been widely used to degrade pollutants, such as pesticides, in wastewater in a process referred to as Advanced Oxidation Process. The generation of hydroxyl-radicals can also occur in the gas phase by UV-C illumination of hydrogen peroxide mist and ozone gas within a batch or continuous process. In the following presentation the principle of the hydroxyl-radical process will be described and provide examples on decontaminating a broad range of fruit and vegetables. In addition to pathogen inactivation, the gas phase-hydroxyl radical treatment can be applied to extend the shelf-life of fresh produce and degrade pesticides such as chlorpyrifos. The process is versatile and has also been applied to decontaminate non-food surfaces such as N95 masks and reusable plastic crates. In more recent research a portable device using UV-LED and electrostatic misting has been developed for use in food service facilities. The hydroxy-radical process represents an effect method to enhance food safety, extend shelf-life while saving on large volumes of water used in the traditional fruit & vegetable wash process.

Dr. Siyun Wang, Associate Professor, Department of Food Science – University of British Columbia

Dr. Siyun Wang is an Associate Professor and the principal investigator of the Wang Lab of Molecular Food Safety (http://foodsafety.landfood.ubc.ca) at the University of British Columbia, where she teaches and conducts research on ensuring a safer food supply system. She has authored over 50 peer-reviewed papers and book chapters.  Siyun received her BSc in Pharmacy from Fudan University in 2005 and PhD in Biology from Illinois Institute of Technology in 2010. Prior to joining UBC in Jan 2013, she was a postdoctoral associate at Cornell University.

Awards she received included Notable Distinctions at UBC, the Food Safety Award from BC Food Protection Association, the Young Researcher Initiative from the European Food Safety Authority, and the scholarship for young women scientists underrepresented in STEM from the US National Science Foundation. Siyun currently serves as an Associate Editor of Current Research in Food Science, an editorial board member of Journal of Food Protection and Food Microbiology, and a review editor of Frontiers in Microbiology|Phage Biology.

At UBC, Siyun serves as the graduate advisor of the Food Science Program as well as sits on the COVID-19 expert panel as a food safety expert.


Bacteriophages and their application in ensuring fresh produce safety

Verocytotoxin-producing E. coli (VTEC) and Salmonella enterica are causative agents of multiple outbreaks of foodborne illness associated with fresh produce. Controlling of these pathogens in fresh produce is challenging, because contamination can occur at multiple stages through the farm-to-fork continuum. we evaluated the potential of lytic bacteriophages (phages) for controlling pathogens in fresh produce at the postharvest level. Phages are viruses that infect and often kill bacteria through lysis of the bacterial cell wall, but are harmless to humans. The bacterial strains we evaluated possess diverse genetic factors that affect their susceptibility to phage treatments and abilities to contaminate fresh produce. The phage cocktail was able to reduce VTEC/Salmonella on Romaine lettuce, and Salmonella on cantaloupe flesh and alfalfa sprouts up to 3 log, but the effect is phage- and strain-dependent. According to whole genome sequencing results, isolated phages lacked integrase and known pathogenic and virulence genes. Phages remained stable despite host absence at different temperatures, indicating they have potential for applications in produce industry.