Source: CALIFORNIA STATE UNIVERSITY EAST BAY FOUNDATION submitted to NRP
ENHANCING THE SAFETY AND QUALITY OF FRESH PRODUCE AND LOW-MOISTURE FOODS BY WATERLESS NON-THERMAL TECHNOLOGIES
Sponsoring Institution
National Institute of Food and Agriculture
Project Status
COMPLETE
Funding Source
AFRI COMPETITIVE GRANT
Reporting Frequency
Annual
Accession No.
1023525
Grant No.
2015-69003-32075
Cumulative Award Amt.
$1,809,209.67
Proposal No.
2020-06875
Multistate No.
(N/A)
Project Start Date
Sep 1, 2020
Project End Date
Aug 31, 2023
Grant Year
2020
Program Code
[A4131]- Enhancing Food Safety Through Improved Processing Technologies
Recipient Organization
CALIFORNIA STATE UNIVERSITY EAST BAY FOUNDATION
25976 CARLOS BEE BLVD
HAYWARD,CA 94542
Performing Department
Biological Sciences
Non Technical Summary
Our food supply could be vulnerable to multiple pathogens such as bacteria, parasites, and viruses. Consumption of produce and low-moisture foods (LMF), such as nuts, cereals, and spices, has increased significantly in recent decades. These products are highly susceptible to contamination by pathogens from pre-harvest to post-harvest stages. The challenge for food scientists is to develop new technologies that will improve safety and extend the shelf life of food products without compromising safety or sensory properties. Most foods are thermally preserved (i.e., cooking) by subjecting them to high temperature or boiling. However, fresh fruits and vegetables are particularly critical because they are commonly eaten without thermal processing. Nonthermal methods allow for the processing of foods below the temperatures used during pasteurization and canning, allowing minimal changes in flavor and quality while removing pathogens. The purpose of this project is to investigate the emerging nonthermal technologies such as decontaminating lights, gaseous treatment, and cold plasma (ionized atmospheric air, i.e., lightening). These processes are used on an industrial scale for the manufacturing of electronics and medical instruments. Each nonthermal technology has a specific application, and each technology has its merits and limitation. Our approach is to use combinations of technologies to optimize product quality and inactivate pathogens and commercialize the process. With the technology transfer to industry, we expect that processors will spend less money on energy inputs such as energy for heat, water, and chemical passing the savings on the consumer. With the increasing outbreaks associated with fresh produce and LMF, the ability to provide effective microbiological control will be critical to maintaining consumer confidence in the agricultural and food industries, both in the United States and with international trading partners.
Animal Health Component
25%
Research Effort Categories
Basic
25%
Applied
25%
Developmental
50%
Classification

Knowledge Area (KA)Subject of Investigation (SOI)Field of Science (FOS)Percent
7127299110030%
9031129302020%
5011499110120%
7231212202020%
9021430110310%
Knowledge Area
902 - Administration of Projects and Programs; 501 - New and Improved Food Processing Technologies; 712 - Protect Food from Contamination by Pathogenic Microorganisms, Parasites, and Naturally Occurring Toxins; 903 - Communication, Education, and Information Delivery; 723 - Hazards to Human Health and Safety;

Subject Of Investigation
1499 - Vegetables, general/other; 1212 - Almond; 1129 - Berries and cane fruits, general/other; 1430 - Greens and leafy vegetables; 7299 - Research equipment and methods, general/other;

Field Of Science
2020 - Engineering; 1101 - Virology; 1103 - Other microbiology; 3020 - Education; 1100 - Bacteriology;
Keywords
Goals / Objectives
The goal of this study is to develop an integrated project among academia, government, industry partners, and stakeholders to develop effective waterless, non-thermal processing technologies to provide consumers with safe, nutritious, high-quality produce and low-moisture foods, equip Extension agents with the knowledge and tools that they need to influence a change inconsumer perception related to food processing technologies, and facilitate the commercialization of these technologies and dissemination of knowledge through education and outreach.
Project Methods
This research will determine the effects of processing parameters (e.g., concentration, intensity, and time) of light and gaseous treatments, environmental conditions (e.g., temperature and humidity), and product characteristics (e.g., tissue makeup, surface structure, and roughness) on the inactivation and survival of foodborne bacterial, viral, and parasitic pathogens, such as Shiga toxin-producing Escherichia coli, Salmonella spp., Listeria monocytogenes, Cryptosporidium parvum, and human norovirus. Food products will include fresh and fresh-cut leafy greens, root and berry produce, and LMF, such as whole peppercorn and almond. Logarithmic reductions of bacterial pathogens and parasites will be determined using a viable count method and a combination of cell culture and mouse models, respectively. Since human norovirus cannot be grown in cell culture, the inactivation of human norovirus will be determined using a novel published receptor-binding assay, and the infectivity will be further verified in a published gnotobiotic pig model. Similarly, work with the protozoan parasite Cryptosporidium will be used to assess Cyclospora, which cannot be grown in cell culture or in animal models. Mathematical models will be developed to describe inactivation kinetics. The effects of these processing technologies on product quality attributes, such as sensory, color, texture, nutrients, and consumer acceptance, will be evaluated using instruments in conjunction with sensory panels. Technologies that are capable of achieving the desired performance standards for hazard reduction, nutrition, and quality will be optimized for industrial applications. By working with growers, processors, economic researchers, and environmental scientists, the costs, benefits, and environmental impact of implementing the technologies will also be determined.For education, Students training in emerging nonthermal technologies, parasitology, microbiology, virology, and food safety will be conducted.Methods for carrying extension components include 1) access consumer perception of food processing technologies, 2) develop educational materials, 3) provide training to Cooperative Extension agents, 4) extension agent training, and 5) eXtension webinar series.The project team has established a plan for evaluating project progress to achieve the research, education, and education objectives and ensure the successful completion of the project. The plan includes a master timeline/milestones that indicates the specific tasks, time, and milestones for each participating institution. A template of performance standard is to be used by the team member to list tasks, timeline, milestones, and indicators of completion for establishing his/her annual work plan. The effectiveness of the research, education, and extension program will be evaluated.

Progress 09/01/20 to 08/31/23

Outputs
Target Audience:We developed and optimized non-thermal processing technologies to inactivate pathogens in high-risk foods. We targeted food processors, packagers, and retailers that wish to optimize commercial equipment and provide optimal processing parameters for produce and low-moisture foods (LMF). Other target audiences included consumer groups; regulators in the US, Canada, EU, and, extension, regulators globally; researchers in the field of food safety, with particular emphasis on those developing, evaluating, and optimizing non-thermal interventions to inactivate human pathogens. The commercialization of these technologies will significantly improve the safety of the food supply while benefiting the processors by providing sustainable alternative methods of non-thermal processing. These benefits will be passed on to the consumer by creating products that are safe with high sensory and nutrition quality. Information from this project was disseminated through websites and surveys and used to develop educational materials for training students, extension agents, consumers, and other educators. Extension publications (infosheets) have been produced for Extensionagents to utilize as resources. Because Extension agents interact with clientele/consumers, the infosheets are subsequently being used to educate the general public about food processing technologies. Additionally, the results have been published and presented at the conferences. The technologies and knowledge generated from this project improve food safety and benefit public health and the U.S. economy. Changes/Problems: The system did not accept any "Journal Articles or Presentations" that were prior to 2020. Therefore,publications between 2015 and 2020 as part of the entire project but before the year the grant was transferred to CSUEB were not entered. Publications that were already reported with the previous report were not re-entered. What opportunities for training and professional development has the project provided?This CAP project strengthens the collaboration among all the participant institutions. Co-PDs, students, postdoc fellows, lab technicians, and visiting scholars working on this project present their progress in the virtual lab meetings and quarterly project progress meetings. In addition to graduate students in U.D., VT, OSU, and TTU, we have trained graduate students from Washington State University, the University of California at Davis, and the University of California at Berkeley. Graduate students, visiting scientists, and postdocs have been trained extensively in prototype development, microbiology, molecular biology, virology, and engineering and have been given the opportunity to present their findings professionally. The virtual stakeholder meetings have allowed graduate students and postdocs to communicate with industrial and academic partners. These interactions are a pivotable moment in early investigators and can help to determine future career paths. Many postdocs and graduate student are now pursuing their independent careers as researchers or independent investigators. This project has supported 12 postdoctoral scientists, 8 Master's level and 11 Ph.D.'s level graduate students, and 7 visiting scientists. How have the results been disseminated to communities of interest?Results have been shown to collaborators on the project and board members during virtual quarterly meetings. Results have been disseminated to target audiences through peer-reviewed journal publications and presented virtually at the Institute of Food Technology (IFT) Annual Meeting, and the International Association for Food Protection (IAFP) meeting. There have been several opportunities to present research results to FDA and FSIS scientists, which has facilitated technology transfer to these regulatory agencies. Information on various mitigation technologies and advances in food protection has been included in regional trainings to support the FDA Produce Safety Rule. Dissemination has been via direct communication of research progress to stakeholders in the industry via virtual meetings, telephone, and email. Information has been shared in an educational context through inclusion in course materials. Infosheets have been distributed and shared with Extension Agents and consumers. Extension publications are available for view and download by Extension agents, consumers, and other educators through the Virginia Cooperative Extension publications website. We have communicated with stakeholders through a series of stakeholder meetings. Onsite meetings were conducted at WRRC in 2019 and 2020. In 2022, a virtual meeting was conducted on Zoom and organized in a manner to systematically gather feedback. Barriers and facilitators to scaling up non-thermal technologies were accessed by hosting breakout sessions following the technical presentation. The breakout session revealed that adaptability, cost, and perceived knowledge inform stakeholders' decisions when adopting new technologies. In 2023, a hybrid stakeholder meeting was hosted over Zoom and at WRRC to further discuss how to deliver novel technologies to the industry at a commercial scale. What do you plan to do during the next reporting period to accomplish the goals?None. This is the final report.

Impacts
What was accomplished under these goals? This project has accomplished the following milestones: Developed effective decontamination treatments for tomatoes, baby-cut carrots, peppercorns, apples, and almonds using gaseous ClO2. Target pathogens included E.coli O157:H7, Listeria monocytogenes, Salmonella, Aspergillus flavus, Cryptosporidium, and Eimeria as a surrogate for Cyclospora. Log reduction ranged from 0.5-6.2 CFU/g and was primarily driven by the intrinsic moisture content of the food. Baby-cut carrots demonstrated the highest log reduction, and gaseous ClO2 completely eliminated the pathogens. Overall, ClO2 treatments that achieved more than 4 log reductions of Salmonella did not significantly affect the sensory or nutritional quality of grape tomatoes. Larger-scale studies simulating a pilot-scale process were conducted to identify the effective treatment parameters that may be useful for commercial-scale applications. The cumulative ClO2 exposures of 300, 1300, and 1600 ppm-h caused >4.0-log CFU/g reductions of the pathogens on baby-cut carrots, tomatoes, and blueberries, respectively. The treatment was the most effective against the pathogens on baby-cut carrots, likely due to the moisture on the surface of the peeled carrots. For nuts and spices, a higher dose level is needed. A significant (P<0.05) log reduction of L. innocua was achieved by pilot-scale and semi-industrial scale (1.4 ± 0.2 and 1.2 log CFU/mL) gaseous ClO2 treatments in the cold storage of fresh apples (750 pounds of apples) without adversely affecting fruit quality. Investigate the effect of water activity (aw) on the inactivation ofListeria monocytogenes using gaseous chlorine dioxide (ClO2 (g)). Water activity, ClO2 concentration, and time as critical parameters for inactivating L. monocytogenes and may be used to design effective ClO2 (g) treatment processes t in low-moisture foods. Designed and built a refrigerator size-controlled atmosphere ClO2 treatment chamber for the treatment of apples and optimized dose and duration of treatment. The inactivation of Listeria innocua by gaseous ClO2 treatment for 1h was approximately 3 log CFU/ml. The quality of the ClO2-treated apples after cold storage for four months remained. Developed industrial-scale treatment protocols for high and low doses of gaseous ClO2 on in-hull almonds fumigation to reduce the presence of microorganisms. A headspace concentration of 0.2 ppm ClO2 demonstrated 87.1% reduction ofA. flavuson in-hull almonds. The protocols can be applied to stockpiles, shipping containers, and during warehouse storage. Observed the suppression of the microbial flora (aerobic bacteria, coliforms, yeasts, and molds) on treated almonds as compared to the control. High humidity is critical for gaseous ozone treatments to preserve quality and exert high antimicrobial effectiveness. Dry ozone treatments had limited effectiveness against Salmonella on tomatoes and negatively impacted the fruit quality during post-treatment storage. However, increasing humidity during ozone treatment not only increased the efficacy of ozone against Salmonella by 99.9% on tomatoes, but also minimized the ozone-induced deterioration in the sensory and nutritional quality of the fruit. Integrated non-thermal technologies for pilot scale studies based on a modified tunnel carrot washing line and/or vibrating convey line to treat produce and low-moisture foods. The design for our system was adapted to optimize the treatment of technology-compatible produce commodities with cold plasma and blue light (405nm) to reduce the number of pathogens present without disrupting the organoleptic or sensory properties of the product. Demonostrated reductions of MNV and TV with 405 light, and effects of incorporated photoactivator compounds. Elucidation of the efficacious modes of action confirmed that 405 light did not significantly inactivate Tulane virus, but when singlet oxygen enhancers were added the virus was inactivated by 405nm light. Salmonella is more easily killed by cold plasma on tomatoes than on lettuce when the two are mixed together as a salad. In this study, the direction of transfer of Salmonella from lettuce to tomato specifically showed greater kill than the reverse (0.29 log CFU/g) (P < 0.002). Evaluated the impact of cold atmospheric plasma (CP) on the viability of Cryptosporidium parvum oocysts on cilantro. Overall, CP treatment significantly reduced oocyst infectivity compared with the 0-s treatment control (P< 0.02). Log inactivations of oocysts observed on cilantro were 0.84, 1.23, and 2.03 for the 30-, 90-, and 180-s treatment times, respectively. Drying and darkening of cilantro leaves was observed with treatments longer than 30 s. Dry and water-assisted pulsed light (PL) treatments were evaluated on Salmonella-contaminated blueberries. The water-assisted PL method significantly reduced Salmonella levels, outperforming dry PL, without affecting shelf life or quality. The performance of a large-scale decontamination system based on a washing process in combination with pulsed light (PL) exposure and H2O2/chlorine was evaluated. The combined PL-H2O2 treatment in general, showed a better inactivation effect of Salmonella on tomatoes than the PL alone treatment. Three UV treatment forms were tested on Salmonella-inoculated tomatoes and fresh-cut lettuce: dry UV, wet UV, and water-assisted UV. Water-assisted UV proved most effective. Water-assisted UV, especially when combined with chlorine, proved as effective as or better than chlorine washing. Two light systems, pulsed light and UV, for decontamination of fresh produce were evaluated and compared. Results demonstrated that the two systems showed similar decontamination effect on fresh produce, demonstrating that the UV system could be used to replace the pulsed light system to reduce equipment costs. Compared the effectiveness of ultraviolet light (UV), chemical sanitizers, and heat treatments in inactivating Salmonella and preserving almond quality. UV treatment alone was insufficient for Salmonella inactivation. Combined treatments involving chemical solutions and UV were more effective. Heat treatment was superior to UV and sanitizers for raw almond pasteurization. Pulsed light can reduce the infectivity ofC. parvumoocysts on cilantro, mesclun, lettuce, spinach, and tomato and with further optimization, could have potential applications in post-harvest processing of these commodities. Our systematic reconstruction of the transcriptional regulatory networks across different dosages of O3 xenobiosis showed that gene modules associated with pathogenicity, stress response, transcriptional regulation, and transport processes play important roles. From a food safety standpoint, introducing combinations of treatments (i.e., optimal hurdles) might be an attractive alternative to effectively control bacterial pathogens without promoting adaptation or mutation, which are the main causes of perennial outbreaks. Completed survey assessing Extension agent knowledge, perceptions, and purchasing intention relative to specific processing technologies. Data was used to inform the creation of educational materials and training. Data is being prepared for publication in a peer-reviewed scientific journal. Peer-reviewed educational materials were distributed to Extension Agents, consumers, and stakeholders. We worked with other grant members to ensure each technology is well represented from a scientific standpoint while still using lower-level language to ensure understanding from all potential readers.

Publications

  • Type: Journal Articles Status: Published Year Published: 2023 Citation: Guan, J, Lacombe, A., Rane, B., Zhang, Y., Tang, J., Shyam, S., Wu, V.C.H, (2023). The Stress Response of Listeria monocytogenes Inoculated on Fresh Apples Exposed to Gaseous Chlorine Dioxide. Journal of Food Safety (submitted 09/27/23). Published
  • Type: Journal Articles Status: Published Year Published: 2023 Citation: Rane, B. Lacombe, A., Guan, J., Zhang, Y., Bridges, D.F., Tang, J., Shyam, S., Wu, V.C.H, (2023). Molecular approaches to investigate the effect of gaseous chlorine dioxide (ClO2) on A. flavus aflatoxin production on almonds. Food Chemistry (submitted 09/25/23). Published
  • Type: Journal Articles Status: Published Year Published: 2023 Citation: Guan, J, Lacombe, A., Rane, B., Tang, J., Shyam, S., Wu, V.C.H, (2023) Scaling up Gaseous Chlorine Dioxide (ClO2) Treatment in the Cold Storage of Fresh Apples, LWT (in preparation) (NIFA support acknowledged) Published
  • Type: Journal Articles Status: Published Year Published: 2023 Citation: Rane, B., Lacombe, A., Friedman, Pratt, P., Wu, V.C.H. (2023) Navel orangeworm (NOW) development response on gaseous chlorine dioxide treatments. Journal of Stored Product (Submitted 09/29/23). (NIFA support acknowledged) Published
  • Type: Journal Articles Status: Published Year Published: 2023 Citation: Lacombe, A., Wu, V.C.H, (2023). The effects of sanitizing hurdles against foodborne pathogens during blueberry processing. Food Control, https://doi.org/10.1016/j.foodcont.2023.109981 (NIFA support acknowledged) Published
  • Type: Journal Articles Status: Published Year Published: 2020 Citation: Bhargavi Rane, Alison Lacombe, Shyam Sablani, David F. Bridges, J. T., & Jiewen Guan, V. C. H. W. (2020). Effects of moisture content and mild heat on the ability of gaseous chlorine dioxide against Salmonella and Enterococcus faecium NRRL B-2354 on almonds. Food Control. https://doi.org/https://doi.org/10.1016/j.foodcont.2020.107732 Published
  • Type: Journal Articles Status: Published Year Published: 2022 Citation: Bridges, David F., Lacombe, A. & Wu, V. C. H. 2022 Fundamental Differences in Inactivation Mechanisms of Escherichia coli O157:H7 Between Chlorine Dioxide and Sodium Hypochlorite. Front Microbiol. 2022; 13: 923964. Published
  • Type: Journal Articles Status: Published Year Published: 2021 Citation: Bridges, David F., Lacombe, A. & Wu, V. C. H (2021). Integrity of the Escherichia coli O157:H7 Cell Wall and Membranes After Chlorine Dioxide Treatment. Frontiers in Microbiology. 11. Published
  • Type: Journal Articles Status: Other Year Published: 2023 Citation: How Virginia Extension Agents Engage with the Public about Food Processing Perceptions (Working title; In preparation)
  • Type: Journal Articles Status: Other Year Published: 2023 Citation: Stakeholder Feedback on Waterless, Non-Thermal Processing Technology Coordinated Agriculture Project (Working title; In Preparation)
  • Type: Conference Papers and Presentations Status: Published Year Published: 2021 Citation: Shu X, Singh M, Karampudi NBRK, Bridges D, Kitazumi A, Wu VCH, De los Reyes BG (2021) Responses of Escherichia coli and Listeria monocytogenes to ozone treatment on non-host tomato: Efficacy of intervention and evidence of induced acclimation. American Society of Microbiology Annual Conference, 2019 (Abstract). Published
  • Type: Conference Papers and Presentations Status: Published Year Published: 2020 Citation: Craighead S, S Hertrich, G Boyd, J Sites, B.A. Niemira, K.E. Kniel. 2020. Cold atmospheric plasma jet inactivates Cryptosporidium parvum oocysts on cilantro. J Food Prot (2020) 83(5):794800. Published
  • Type: Conference Papers and Presentations Status: Published Year Published: 2020 Citation: Fan, X. 2020. Application of gaseous ozone as in-package and fumigation treatments to enhance microbial safety and maintain quality of tomato fruit. American Chemical Society Annual Meeting, San Francisco, CA August 16-20, 2020. Published
  • Type: Conference Papers and Presentations Status: Published Year Published: 2023 Citation: Wang, W., Ngo, H., Jin, T., Fan, X. Gaseous chlorine dioxide reduced Salmonella populations on almonds, while accelerating lipid oxidation during storage. IAFP meeting, July 16 19, 2023. Toronto, Ontario, Canada. Published
  • Type: Conference Papers and Presentations Status: Published Year Published: 2023 Citation: Fan, X. 2023. Undesirable chlorine byproducts in water, fresh produce and nuts. International Association for Food Protection Annual Meeting, July 16-19, 202.3 Toronto, Ontario, Canada. Published
  • Type: Conference Papers and Presentations Status: Published Year Published: 2023 Citation: Fan, X. 2023. Chlorine dioxide fumigation of fresh produce and nuts: microbial reduction and quality change. American Chemical Society Annual Meeting, San Francisco, CA, August 13 - 17, 2023. Published
  • Type: Conference Papers and Presentations Status: Published Year Published: 2023 Citation: Lacombe, A., V.C.H. Wu*, L.H. Schonberger, and B.R. Renee. Outcomes of stakeholder meeting discussing outreach efforts of waterless, non-thermal food processing technology USDA coordinated agriculture project / speaker's corner. 2023. International Association for Food Protection (IAFP) Annual Meeting. Toronto, Canada. Published
  • Type: Conference Papers and Presentations Status: Published Year Published: 2023 Citation: Lacombe, A., B. Rane, and V.C.H. Wu*. Reduction of Aspergillus flavus and aflatoxin AFB1 on almond kernels using gaseous chlorine dioxide fumigation. 2023. Institute of Food Technologist (IFT) Annual Meeting. Chicago, IL. Published
  • Type: Conference Papers and Presentations Status: Published Year Published: 2022 Citation: Lacombe, A and V.C.H. Wu*. Implementation of gaseous chlorine dioxide fumigation to improve post-harvest stockpile management of almonds. 2022 The Almond Conference. California. Dec. 7, 2022. Published
  • Type: Conference Papers and Presentations Status: Published Year Published: 2021 Citation: Rane, B., A. Lacombe, L. Lucero, P. Pratt, and V.C.H. Wu*. 2021. Gaseous chlorine dioxide fumigation against Aspergillus flavus molds and aflatoxins on almonds. The Almond conference.v Published
  • Type: Conference Papers and Presentations Status: Published Year Published: 2020 Citation: Lacombe, A. D. F. Bridges, and V.C.H. Wu*. 2020. Strain specific response of Escherichia coli biofilms to chlorine dioxide . International Association for Food Protection (IAFP) Annual Meeting. Virtual. Published
  • Type: Conference Papers and Presentations Status: Published Year Published: 2020 Citation: Guan, J., A. Lacombe, J. Tang, D. F. Bridges, B. Rane, S. Sablani, and V.C.H. Wu*. 2020. Modeling the efficacy of gaseous chlorine dioxide against Listeria on apple surfaces. International Association for Food Protection (IAFP) Annual Meeting. Virtual. Published
  • Type: Conference Papers and Presentations Status: Published Year Published: 2020 Citation: Rane, B., A. Lacombe, D. Bridges, J. Guan, S. Sablani, J. Tang, and V.C.H. Wu*. 2020. Effect of gaseous chlorine dioxide on aflatoxin-producing fungi in almonds. Institute of Food Technologist (IFT) Annual Meeting. Virtual. Published
  • Type: Conference Papers and Presentations Status: Published Year Published: 2020 Citation: Lacombe, A. and V.C.H. Wu*. 2020. Food safety technologies in the era of the COVID-19 pandemic. ACS National Meeting & Exposition. San Diego, CA Published
  • Type: Conference Papers and Presentations Status: Published Year Published: 2020 Citation: Chai, H.-E., Hwang, C.-A., Huang, L., Wu, V.C.H., and Sheen, L.-Y. Efficacy of gaseous chlorine dioxide for decontamination of almonds and peppercorns. 2020 IFT Annual Meeting. Published
  • Type: Journal Articles Status: Published Year Published: 2020 Citation: Fan, X., Wang, W. 2020. Quality of fresh and fresh-cut produce impacted by nonthermal physical technologies intended to enhance microbial safety. Critical Reviews in Food Science and Nutrition, 62:362-382. Published
  • Type: Journal Articles Status: Published Year Published: 2021 Citation: Fan, X. 2021. Gaseous ozone to preserve quality and enhance microbial safety of fresh produce: Recent developments and research needs. Comprehensive Reviews in Food Science and Food Safety 20:4993-5014. Published
  • Type: Journal Articles Status: Published Year Published: 2022 Citation: Jiang, T., Guo, F., Fang, T., Hwang, C.-A., and Huang, L. 2022. Efficacy of gaseous chlorine dioxide generated by sodium chlorite - carbon dioxide reaction on safety and quality of blueberries, cherry tomatoes, and grapes. Food Control. https://doi.org/10.1016/j.foodcont.2022.109288. Published
  • Type: Journal Articles Status: Published Year Published: 2021 Citation: Park, H., Huang, L., Chen, G., Hwang, C.-A. 2021. Effect of water activity on inactivation of Listeria monocytogenes using gaseous chlorine dioxide  A kinetic analysis. Food Microbiology. https://doi.org/10.1016/j.fm.2020.103707. Published
  • Type: Journal Articles Status: Published Year Published: 2022 Citation: Wang, L. Fan, X., Gurtler, J. 2022. Reduction of Salmonella enterica Typhimurium populations and quality of grape tomatoes treated with dry and humidified gaseous ozone. Postharvest Biology and Technology. 193, p.112061. Published
  • Type: Journal Articles Status: Published Year Published: 2023 Citation: Wang, W., Smith, D.J., Ngo, H., Jin, ZT., Alyson, M., Fan. X. 2023. Lipid oxidation and volatile compounds of almonds as affected by gaseous chlorine dioxide treatment to reduce Salmonella populations. J. Agric. Food Chem. 71(13), pp.5345-5357. Published
  • Type: Journal Articles Status: Published Year Published: 2020 Citation: Craighead S, Hertrich S, Boyd G, Sites J, Niemira BA, Kniel KE. 2020. Cold Atmospheric Plasma Jet Inactivates Cryptosporidium parvum Oocysts on Cilantro. J Food Prot. 1;83(5):794-800. doi: 10.4315/0362-028X.JFP-19-442. PMID: 32318724. Published
  • Type: Journal Articles Status: Published Year Published: 2022 Citation: Xu, S. and Chen, H. 2022. Vacuum packaging improved inactivation efficacy of moderate dry heat for decontamination of Salmonella on almond kernels. Int. J. Food Micro. 379: 109849. DOI: 10.1016/j.ijfoodmicro.2022.109849. Published
  • Type: Journal Articles Status: Published Year Published: 2023 Citation: Xu, S. and Chen, H. 2023. Mild heat treatment achieved better inactivation of Salmonella and preservation of almond quality than ultraviolet light and chemical sanitizers. Int. J. Food Micro. 399: 110253. doi: 10.1016/j.ijfoodmicro.2023.110253. Published
  • Type: Journal Articles Status: Published Year Published: 2023 Citation: Xu, S. and Chen, H. 2023. The influence of almonds water activity and storage temperature on Salmonella survival and thermal resistance. Food Micro. 113: 104269. doi: 10.1016/j.fm.2023.104269. Published


Progress 09/01/21 to 08/31/22

Outputs
Target Audience:We expect to develop and optimize non-thermal processing technologies to inactivate pathogens in high-risk foods. We plan to target food processors, packagers, and retailers that wish to optimize commercial equipment and provide optimal processing parameters for produce and low-moisture foods (LMF). Other target audiences include consumer groups; regulators in the US, Canada, EU, and, extension, regulators globally; researchers in the field of food safety, with particular emphasis on those developing, evaluating, and optimizing non-thermal interventions to inactivate human pathogens. The commercialization of these technologies will significantly improve the safety of the food supply while benefiting the processors by providing sustainable alternative methods of non-thermal processing. These benefits will be passed on to the consumer by creating products that are safe with high sensory and nutrition quality. Information from this project will be disseminated through websites and surveys and used to develop educational materials for training students, extension agents, consumers, and other educators. Extension publications (infosheets) have been produced for Extension agents to utilize as resources. Because Extension agents interact with clientele/consumers, the infosheets are subsequently being used to educate the general public about food processing technologies. Additionally, the results will be published and presented at the conferences. Hopefully, as the pandemic is coming to an end, future efforts will also focus on outreach and education using non-written publication methods. The application of the technologies will significantly improve food safety and benefit public health and the U.S. economy. Changes/Problems:The global pandemic on COVID-19 had caused immeasurable challenges that were addressed through resilience and resourcefulness. However, during this time, we continued to deal with issues related to Center/lab/University closures and phased reopening associated with COVID. We experienced complications due to COVID in student recruitment. COVID-19 has continued to impact our ability to maintain progress in the project, with limited opportunities to engage in professional development and in-person training with Extension agents. However, we were able to host virtual meetings, including our annual grantee and stakeholder meeting. We anticipate that our research will begin to progress normally from this period forward. What opportunities for training and professional development has the project provided?This CAP project strengthens the collaboration among all the participant institutions. Co-PDs, students, postdoc fellows, lab technicians, and visiting scholars working on this project present their progress in the virtual lab meetings and quarterly project progress meetings. In addition to graduate students in U.D., VT, OSU, and TTU, we have trained graduate students from Washington State University, the University of California at Davis, and the University of California at Berkeley. Graduate students, visiting scientists, and postdocs have been trained extensively in prototype development, microbiology, molecular biology, virology, and engineering and have been given the opportunity to present their findings professionally. The virtual stakeholder meetings have allowed graduate students and postdocs to communicate with industrial and academic partners. These interactions are a pivotable moment in early investigators and can help to determine future career paths. Many postdocs and graduate student are now pursuing their independent careers as researchers or independent investigators. How have the results been disseminated to communities of interest?Results have been shown to collaborators on the project and board members during virtual quarterly meetings. Results have been disseminated to target audiences through peer-reviewed journal publications and presented virtually at the Institute of Food Technology (IFT) Annual Meeting, and the International Association for Food Protection (IAFP) meeting. There have been several opportunities to present research results to FDA and FSIS scientists, which has facilitated technology transfer to these regulatory agencies. Information on various mitigation technologies and advances in food protection has been included in regional trainings to support the FDA Produce Safety Rule. Dissemination has been via direct communication of research progress to stakeholders in the industry via virtual meetings, telephone, and email. Information has been shared in an educational context through inclusion in course materials. Infosheets have been distributed and shared with Extension Agents and consumers. We have hosted virtual stakeholder meetings on Zoom. Valuable comments and suggestions were collected for future guidance. What do you plan to do during the next reporting period to accomplish the goals?Cumulative research activities will be used to focus scale-up efforts on chlorine dioxide, U.V., and cold plasma systems. The next step is to work with the industry to improve the engineering controls to enhance microbial kill while protecting worker safety and complying with local, state, and federal regulations. Critical aspects should be taken into consideration and analyzed, including a larger number of fresh apples (more than one apple bin, i.e., 10 bins), longer storage times (more than 3 months), pilot-scale and semi-industrial scale treatment in CA cold storage, optimized concentrations and times for diverse commercial conditions, chemical residue analysis, and any negative impact on the existing cold storage facilities. More antimicrobial mechanism studies focusing on the analysis of more relevant genes or even whole-genome sequencing of L. monocytogenes on apple surfaces exposed to different initial inputs and exposure times of gaseous ClO2 are needed. This helps further understand the stress response systems that facilitate L. monocytogenes surviving sublethal gaseous ClO2 exposure. The mechanism information can provide insights to optimize the inactivation conditions and ensure the effectiveness of gaseous ClO2. The required goals for the industrial scale up of gaseous ClO2 have been met. This project can provide a baseline to develop and improvise the gaseous ClO2 application methods based on specific industrial requirements. Furthermore, this technology can be applied to inhull almonds that are harvested and stockpiled for storage to be dried. This will help to address the initial problem of microbial contaminations and help control the toxin formations. We plan to continue to work on the decontamination of almonds. Further optimization of the processing parameters will enhance the Salmonella inactivation efficacy. Hurdle technology involving thermal and UV light will be explored. Additionally, work is being completed regarding the chlorine dioxide inactivation of Cryptosporidium parvum on fresh produce items. Outreach will continue to involve potential commercial partners in scale-up and commercialization. We will continue to integrate our seminal findings from this project to make our final recommendations to the target audience in the food technology community. We plan to publish more manuscripts. In the upcoming reporting period, our extension effort will lead us to Submit the "How Virginia Extension Agents Engage with the Public about Food Processing Perceptions" manuscript for publication Complete our analysis of data from the 2022 Stakeholder Meeting and submit it for publication Continue to develop a professional development opportunity for Extension agents to increase their awareness of the processing technologies.

Impacts
What was accomplished under these goals? This year, the project team has continued under restricted activity due to the COVID-19 pandemic for the first half of the year and phased-returned to the workplace during the second half of the year. Activities have focused on publishing existing data (see publications). Administrative actions have been completed for the no-cost extension. The 2022 Stakeholder and Annual Grantee Meeting took place successfully virtually, where we were able to receive feedback on our Research and Extension/outreach work. The stakeholder feedback is being analyzed for publication. Some of our labs were able to operate under 50% building occupation restriction, allowing us to accomplish the following milestones: Development of a cold storage system with integrated gaseous ClO2 industrial used with a modified atmosphere. The refrigeration system supports the shelf-life extension and pathogen reduction of up to 750 pounds of apples for one month. Optimization of gaseous ClO2 (1.2 g precursor/kg of produce) dosages for the inactivation of pathogens on fresh apple surfaces during cold storage. Significant reductions (1.4 ± 0.2 and 1.2 log CFU/mL) without visual and chemical impacts on apple quality. Examined for the first time the stress response of L. monocytogenes on apple surfaces under optimized dose treatment by investigating the gene expression of two relevant virulence (hly) and stress (clpC) genes. Developed protocols for high and low dose of gaseous ClO2 on in-hull almonds fumigation to reduce the presence of background molds thus preventing toxin production. Gaseous ClO2 treatments on almond kernels activated the defense mechanism of A. flavus and underwent a genetic change on almonds to adapt and survive in a low water activity environment. Gaseous ClO2 can be used as an antifungal to reduce A. flavus molds on almonds by interfering with its metabolism pathway Our studies revealed that ozone (O3) treatment altered the expression of genes associated with pathogenicity, stress response, cell motility, transcriptional regulation, primary metabolism, and transport in both E. coli and L. monocytogenes. From a food safety standpoint, introducing combinations of relatively mild intervention treatments (i.e., optimal cocktail) might be an attractive alternative to effectively control bacterial pathogens without promoting adaptation or mutation, which are the main causes of perennial outbreaks. We developed a vacuum packaging in combination with 4-h heat treatment of almonds with an initial aw of 0.43 or 8-h heat treatment of almonds with an initial aw of 0.33 and achieved a ≥ 5-log reduction of Salmonella. Those two combinations resulted in very little weight loss (≤ 0.05%), insignificant color change (?E ≤ 1.26), and unnoticeable change in the visual appearance of almonds, demonstrating that they could be potentially used for raw almond pasteurization. We studied the effects of gaseous chlorine dioxide at varying treatment times on Cryptosporidium parvum on baby-cut carrots and grape tomatoes. After tomatoes were treated with gaseous chlorine dioxide for one hour, a 4.82-log reduction was shown. After three hours of treatment with gaseous chlorine dioxide, C. parvum remained undetectable. For carrots, one hour of gaseous chlorine dioxide treatment resulted in a 3.6-log reduction of C. parvum. Carrots that were treated for three hours showed a 5.2-log reduction of C. parvum. Water activity was measured for each produce type before and after exposure to treatment. There was no significant change in water activity after 1 hour or 3 hours of treatment with gaseous chlorine dioxide for baby-cut carrots or grape tomatoes.

Publications

  • Type: Book Chapters Status: Published Year Published: 2021 Citation: Shu X, Singh M, Karampudi NBRK, Bridges D, Kitazumi A, Wu VCH, De los Reyes BG (2021) Responses of Escherichia coli and Listeria monocytogenes to ozone treatment on non-host tomato: Efficacy of intervention and evidence of induced acclimation. Cold Spring Harbor Laboratory Press bioRxiv doi: https://doi/0.1101/2021.08.13.456288.
  • Type: Journal Articles Status: Published Year Published: 2021 Citation: Shu X, Singh M, Karampudi NBR, Bridges D, Kitazumi A, Wu VCH, De los Reyes BG (2021) Responses of Escherichia coli and Listeria monocytogenes to ozone on non-host tomato: Efficacy of intervention and evidence of induced acclimation. PLoSONE 16(10):e0256324, https://doi.org/ 10.1371/journal.pone.0256324.
  • Type: Journal Articles Status: Published Year Published: 2021 Citation: Fan, X. 2021. Gaseous Ozone to Preserve Quality and Enhance Microbial Safety of Fresh Produce: Recent Developments and Research Needs. Comprehensive Reviews in Food Science and Food Safety. https://doi.org/10.1111/1541-4337.12796.
  • Type: Journal Articles Status: Published Year Published: 2021 Citation: Song, Y., Fan, X. 2021. Hydrogen peroxide residue on tomato, apple, cantaloupe, and Romaine lettuce after treatments with cold plasma-activated hydrogen peroxide aerosols. Journal of Food Protection. (8): 13041308.
  • Type: Journal Articles Status: Published Year Published: 2021 Citation: Liu, X., Fan, X., Wenli, W., Yao, S, Chen, H. 2021. Pasteurization of raw almonds using pulsed light combined with prior water dipping. International Journal of Food Microbiology. https://doi.org/10.1016/j.foodcont.2021.107946.
  • Type: Journal Articles Status: Published Year Published: 2022 Citation: Gurtler, J., Dong, X., Zhong, B., Lee, R. 2022. Efficacy of a mixed peroxyorganic acid antimicrobial wash solution against Salmonella, Escherichia coli O157:H7 or Listeria monocytogenes on cherry tomatoes. Journal of Food Protection. Vol. 85, No. 5, 2022, Pages 773777. https://doi.org/10.4315/JFP-21-368.
  • Type: Journal Articles Status: Published Year Published: 2021 Citation: Tan, J.N., Hwang, C., Huang, L., Wu, V.C., Hsiao, H. 2021. A pilot-scale evaluation of using gaseous chlorine dioxide for decontamination of foodborne pathogens on produce and low-moisture foods. Journal of Food Safety. http://doi.org/10.1111/jfs.12937.
  • Type: Journal Articles Status: Published Year Published: 2021 Citation: Chai, H., Hwang, C., Huang, L., Wu, V.C., Sheen, L. 2021. Efficacy of gaseous chlorine dioxide for decontamination of Salmonella, Shiga toxin-producing Escherichia coli, and Listeria monocytogenes on almonds and peppercorns. Food Control. https://doi.org/10.1016/j.foodcont.2021.108556.
  • Type: Journal Articles Status: Published Year Published: 2020 Citation: Hyeon-Woo, P., Chen, G., Hwang, C., Huang, L. 2020. Effect of water activity on inactivation of listeria monocytogenes using gaseous chlorine dioxide  A kinetic analysis. Food Microbiology. 95/103707. https://doi.org/10.1016/j.fm.2020.103707.
  • Type: Journal Articles Status: Published Year Published: 2021 Citation: Annous, B.A., Buckley, D., Kingsley, D.H. 2021. Efficacy of chlorine dioxide gas against hepatitis A virus on blueberries, blackberries, raspberries, and strawberries. Food and Environmental Virology. 13,241-247. https://doi.org/10.1007/s12560-021-09465-1.
  • Type: Journal Articles Status: Submitted Year Published: 2021 Citation: S, Xu and Chen, H. 2021. Vacuum packaging improved inactivation efficacy of moderate dry heat for decontamination of Salmonella on almond kernels. International Journal of Food Microbiology.
  • Type: Journal Articles Status: Published Year Published: 2021 Citation: Rane, B., Lacombe, A., Sablani, S., Bridges, D. F., Tang, J., Guan, J., & Wu, V. C. (2021). Effects of moisture content and mild heat on the ability of gaseous chlorine dioxide against Salmonella and Enterococcus faecium NRRL B-2354 on almonds. Food Control, 123, 107732.
  • Type: Journal Articles Status: Published Year Published: 2021 Citation: Rane, B., Lacombe, A., Guan, J., Bridges, D. F., Sablani, S., Tang, J., & Wu, V. C. Gaseous chlorine dioxide inactivation of microbial adulterants on whole black peppercorns. Journal of Food Safety, e12948.
  • Type: Journal Articles Status: Published Year Published: 2022 Citation: Rane, B., A. Lacombe, D. Bridges, J. Guan, L. Lucero, S. Sablani, J. Tang, and V.C.H. Wu*. 2022. Reduction of Aspergillus flavus and aflatoxin on almond kernels using gaseous chlorine dioxide fumigation. Food Chemistry. 402 (2023) 134161.
  • Type: Journal Articles Status: Published Year Published: 2021 Citation: Guan, J., A. Lacombe, J. Tang, B. Rane, S. Sablani, and V.C.H. Wu*. 2021. A review: gaseous interventions for food safety control of Listeria monocytogenes in fresh apple cold storage. Front. Micro. 12: 782934.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2020 Citation: Fan, X. Mukhopadhyay, S., Jin, Z. Postharvest intervention technologies to enhance microbial safety of fresh and fresh-cut produce. 2020.. International Fresh Cut Produce Association Annual Conference.


Progress 09/01/20 to 08/31/21

Outputs
Target Audience:We expect to develop and optimize non-thermal processing technologies to inactivate pathogens on high-risk foods. We plan to target food processors, packagers, and retailers that wish to optimize commercial equipment and provide optimal processing parameters for produce and low moisture foods (LMF). Other target audiences include consumer groups; regulators in the US, Canada, EU, and, extension, regulators globally; researchers in the field of food safety, with particular emphasis on those developing, evaluating, and optimizing non-thermal interventions to inactivate human pathogens. The commercialization of these technologies will significantly improve the safety of the food supply while benefiting the processors by providing sustainable alternative methods of non-thermal processing. These benefits will be passed on to the consumer by creating products that are safe with high sensory and nutrition quality. Information from this project will be disseminated through websites and surveys and used to develop educational materials for training students, extension agents, consumers, and other educators. Additionally, the results will be published and presented at the conferences. Hopefully, as the pandemic is coming to an end, future efforts will also focus on outreach and education using non-written publication methods. Application of the technologies will significantly improve food safety and benefit public health and the U.S. economy. Changes/Problems:The global pandemic on COVID-19 had caused immeasurable challenges that were addressed through resilience and resourcefulness. However, during this time, we continued to deal with issues related to Center/lab/University closures associated with COVID. We experienced complications due to COVID in student recruitment. With COVID-19 over the last two years, we have not been able to make efforts to get out and conduct any face-to-face food processing training. Additionally, we had laboratory moves in November through January in this timeframe, which slowed research progress. A no-cost extension is needed. We anticipate that our research will begin to progress normally from this period forward. What opportunities for training and professional development has the project provided?This CAP project strengthens the collaboration among all the participant institutions. Co-PDs, students, postdoc fellows, lab technicians and visiting scholars working on this project present their progress on the virtual lab meetings and quarterly project progress meetings. In addition to graduate students in U.D., VT, OSU, and TTU, we have trained graduate students from Washington State University, University of California at Davis, and University of California at Berkeley. Graduate students, visiting scientists, and postdocs at USDA WRRC have been trained extensively in prototype development, microbiology, molecular biology, virology, and engineering and have been given the opportunity to present their findings professionally. The virtual stakeholder meetings have allowed graduate students and postdocs to communicate with industrial and academic partners. These interactions are pivotable moment in early investigators and can help to determine future career paths. How have the results been disseminated to communities of interest?Results have been shown to collaborators on the project and board members during virtual quarterly meetings. Results have been disseminated to target audiences through peer-reviewed journal publications and presented virtually in the Institute of Food Technology (IFT) Annual Meeting, and International Association for Food Protection (IAFP) meeting. Dissemination has been via direct communication of research progress to stakeholders in the industry via virtual meetings, telephone, and email. Information has been shared in an educational context through inclusion in course materials. Infosheets have been distributed and shared with Extension Agents and consumers. We have hosted virtual stakeholders meeting on Zoom. The topics discussed are: 1) pre-and post-harvest food safety without traditional chlorine washing; 2) cost analysis of upgrading current sanitizing standard operating procedures; 3) pitfalls to avoid when scaling up. It is through these interactions and discussions that we develop actionable food safety aims and programs. What do you plan to do during the next reporting period to accomplish the goals?Cumulative research activities will be used to focus scale-up efforts on chlorine dioxide, U.V., and cold plasma systems. Outreach will continue to potential commercial partners to be involved in scale-up and commercialization. Based on our results so far, the water-assisted U.V. technology can be a potential alternative to chlorine washing for tomatoes. We plan further optimize the water-assisted U.V. technology for tomato decontamination. In addition, we will continue to work on the decontamination of almonds and black peppercorns. We will continue efforts to scale up gaseous ClO2 for commercial application for low moisture foods and produce. We will evaluate critical inputs and parameters that contribute to the reduction in pathogen and create simple engineering controls to augment the process. We plan to publish more manuscripts. Over the next year, we plan to develop professional development training for Extension agents.

Impacts
What was accomplished under these goals? This year, the project team has continued under restricted activity due to the COVID-19 pandemic. Activities have focused on publishing existing data (see publications). Administrative actions have been completed to transfer collaboration paperwork to Cal State East Bay. Some of our labs were able to begin operation under 25% building occupation restriction, allowing us to accomplish the following milestones: We set up lab-scale treatment for treating in-hull almonds with gaseous chlorine dioxide (ClO2). We developed protocols for the lab-scale airtight chambers, Aspergillus flavus inoculation methods for in-hull almonds, 24 h treatments of in-hull almonds with high (20 g) and low precursor doses (5 g). After conducting the lab-scale treatments using high and low doses of gaseous ClO2 on in-hull almonds, a log reduction of ~1 log CFU/g was obtained on A. flavus inoculated on almonds. We conducted lab-scale treatments of almond kernels with gaseous ClO2 (doses- 5, 10, 15, and 20 g) for short and long treatment times (1, 2, 3, 8, 12, and 24 h) to reduce the presence of Aspergillus flavus and its toxins on them. Additionally, these almonds were quantified for the quality damages post-treatment. Longer time treatments with high ClO2 doses obtained a 1 log reduction of A. flavus inoculated on almond kernels. These treatments also reduced 20 ppb of aflatoxins by 70 - 80 % after high dose long time treatments. We maintained stockpiles of in-hull almonds and monitored the deterioration caused by moisture and pest, and set up pilot scale studies for evaluating ClO2 efficacy against mycotoxigenic molds. We designed and built a refrigerator size-controlled atmosphere ClO2 treatment chamber for the treatment of apples. The inactivation of Listeria innocua by gaseous ClO2 treatment for 1h was approximately 3 log CFU/ml. We examined the quality of the treated apples after cold storage for four months and did not observe any damage. Based on the completed research, we have recommended precautionary measures to the food safety industry on the potential impacts of supra-optimal doses of xenobiotic chemicals used for intervention on the development of super-resistant strains through adaptation, acclimation, and even mutation. These findings and recommendations present critical new considerations that could determine potential outbreaks of microbial contamination in the fresh produce processing and supply chain. Inactivation of Cryptosporidium parvum treated with pulsed light was completed and published (see publication). Research regarding the treatment of the protozoan parasite Cryptosporidium parvum with chlorine dioxide was performed on fresh produce. Educational info sheets have been peer-reviewed and finalized. Educational materials have been distributed to Extension Agents, consumers, and stakeholders.

Publications

  • Type: Journal Articles Status: Published Year Published: 2021 Citation: Shu X, Singh M, Karampudi NBRK, Bridges D, Kitazumi A, Wu VCH, De los Reyes BG (2021) Responses of Escherichia coli and Listeria monocytogenes to ozone treatment on non-host tomato: Efficacy of intervention and evidence of induced acclimation. Cold Spring Harbor Laboratory Press bioRxiv doi: https://dpoi/0.1101/2021.08.13.456288.
  • Type: Journal Articles Status: Published Year Published: 2020 Citation: Shu X, Singh M, Karampudi NBR, Kitazumi A, Bridges D, Wu VCH, De los Reyes BG (2020) Xenobiotic effects of chlorine dioxide to Escherichia coli O157:H7 on non-host tomato environment revealed by transcriptional network modeling: Implications to adaptation and selection. Frontiers in Microbiology (Section Food Microbiology) 11:1122, doi:10.3389/fmicb.202.01122.
  • Type: Journal Articles Status: Published Year Published: 2020 Citation: Hyeon-Woo, P., Chen, G., Hwang, C., Huang, L. 2020. Effect of water activity on inactivation of listeria monocytogenes using gaseous chlorine dioxide  A kinetic analysis. Food Microbiology. 95/103707. https://doi.org/10.1016/j.fm.2020.103707.
  • Type: Journal Articles Status: Published Year Published: 2020 Citation: Tan, J., Hwang, C., Huang, L., Wu, V.C., Hsiap, H. 2020. In-situ generation of chlorine dioxide for decontamination of whole cantaloupes and sprout seeds. Journal of Food Protection. 83:287-284. https://doi.org/10.4315/0362-028X.JFP-19-434.
  • Type: Journal Articles Status: Published Year Published: 2020 Citation: Gurtler, J., Keller, S.E., Fan, X., Olanya, O.M., Jin, Z.T. 2020. Survival of desiccation-resistant salmonella on apple slices following antimicrobial immersion treatments and dehydration. Journal of Food Protection. 83:902-909.
  • Type: Journal Articles Status: Published Year Published: 2020 Citation: Fan, X., Song, Y. 2020. Advanced Oxidation Processes to Improve Microbial Safety of Fresh Produce. Journal of Agricultural and Food Chemistry. https://doi.org/10.1021/acs.jafc.0c01381.
  • Type: Journal Articles Status: Published Year Published: 2020 Citation: Oyeyinka, S.A., Olanya, O.M., Ade-Omowaye, B.I., Niemira, B.A. 2020. Non-thermal processing techniques for innovative food processing. Food Science and Technology Trends and Future Prospects. Berlin, Germany: De Gruyter. https://doi.org/10.1515/9783110667462-017.
  • Type: Journal Articles Status: Published Year Published: 2021 Citation: Liu, X., Fan, X, Wang, W., Yao, Y., Chen, H. 2021. Wetting raw almonds to enhance pulse light inactivation of Salmonella and preserve quality. Food Control. 125: 107946. https://doi.org/10.1016/j.foodcont.2021.107946
  • Type: Journal Articles Status: Published Year Published: 2021 Citation: Lacombe, Y.-T. Liao, I. Quintela, and V.C.H. Wu. 2021. Food safety lessons learned from the COVID-19 pandemic. 2020. J. Food Safety. e1287
  • Type: Journal Articles Status: Published Year Published: 2021 Citation: Craighead, C., Huang, R., Chen, H., Kniel, K.E. 2021. The use of pulsed light to inactivate Cryptosporidium parvum oocysts on high-risk commodities (Cilantro, mesclun lettuce, spinach, and tomatoes). Food Control. 126:107965. https://doi.org/10.1016/j.foodcont.2021.107965
  • Type: Journal Articles Status: Under Review Year Published: 2021 Citation: Lacombe, A., Quintela, I., Liao, Y.T., Wu, V.C.H. (2021). Susceptibilities to Perennial E. coli O157:H7 Outbreaks in Californias Leafy Greens Production Continuum. Journal of Food Protection.
  • Type: Journal Articles Status: Published Year Published: 2021 Citation: Rane, B., Lacombe, A., Sablani, S., Bridges, D. F., Tang, J., Guan, J., & Wu, V. C. (2021). Effects of moisture content and mild heat on the ability of gaseous chlorine dioxide against Salmonella and Enterococcus faecium NRRL B-2354 on almonds. Food Control, 123, 107732.
  • Type: Journal Articles Status: Awaiting Publication Year Published: 2021 Citation: Rane, B., Lacombe, A., Guan, J., Bridges, D. F., Sablani, S., Tang, J., & Wu, V. C. Gaseous chlorine dioxide inactivation of microbial adulterants on whole black peppercorns. Journal of Food Safety
  • Type: Journal Articles Status: Published Year Published: 2020 Citation: Guan, J., Lacombe, A., Tang, J., Bridges, D. F., Sablani, S., Rane, B., & Wu, V. C. H. (2020). Use of mathematic models to describe the microbial inactivation on baby carrots by gaseous chlorine dioxide. Food Control, 123(December 2020), 107832.
  • Type: Journal Articles Status: Awaiting Publication Year Published: 2021 Citation: Guan, J., Lacombe, A., Tang, J., Sablani, S., Rane, B., & Wu, V. C. H. (2021). Food Safety Control of Listeria monocytogenes in Fresh Apple Packing Process: Current Interventions and Gaps. Frontiers
  • Type: Journal Articles Status: Published Year Published: 2020 Citation: Arnold, N., L. Yang, R. Boyer. 2020. Safe Processing, Safe Food: Food Processing Infosheets for Extension Educators. Journal of Extension. Volume 58(1). Available at: https://archives.joe.org/joe/2020february/tt7.php
  • Type: Conference Papers and Presentations Status: Published Year Published: 2020 Citation: Fan, X. Mukhopadhyay, S., Jin, Z. Postharvest intervention technologies to enhance microbial safety of fresh and fresh-cut produce. 2020.. International Fresh Cut Produce Association Annual Conference.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2020 Citation: The Use of Non-thermal Approaches to Inactivate Protozoa and Viral Pathogens in Produce. Korea Academy of Science and Technology (KAST). October 2020.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2021 Citation: Educators knowledge and perception of food processing technologies. 2021 Consumer Food Safety Education Conference (3/11/2021) Content: This presentation emphasizes the importance of assessing educators" knowledge and perceptions of food safety topics before they deliver programming to others. Multi-modal educational initiatives (videos, peer-reviewed infosheets, train-the-trainer workshop) were created in response to a survey of Virginia Extension Agents regarding their knowledge of and perceptions towards food processing technologies.
  • Type: Books Status: Published Year Published: 2020 Citation: How is Ozone Gas Used to Process Foods? [Published] Posted on Virginia Cooperative Extension website for public viewing. Available at: https://resources.ext.vt.edu/contentdetail?contentid=2359&contentname=How%20is%20Ozone%20Gas%20Used%20to%20Process%20Foods%3F
  • Type: Books Status: Published Year Published: 2020 Citation: How is Pulsed Light Used to Process Foods [Published] Posted on Virginia Cooperative Extension website for public viewing. Available at: https://resources.ext.vt.edu/contentdetail?contentid=2361&contentname=How%20is%20Pulsed-Light%20Used%20to%20Process%20Foods%3F%20FST-357P
  • Type: Books Status: Published Year Published: 2020 Citation: Why are Foods Processed? [Published] Posted on Virginia Cooperative Extension website for public viewing. Available at: https://resources.ext.vt.edu/contentdetail?contentid=2096&contentname=Why%20are%20Foods%20Processed%3F