Progress 07/01/23 to 06/30/24
Outputs
Target Audience:The target audience reached during this reporting period were academic scholars, farmers, and food industry professionals. The primary means of communication was listserv, individual emails, and conference presentations. Changes/Problems:
Nothing Reported
What opportunities for training and professional development has the project provided? Mentored fivegraduate students (3 MS, 2PhD program) through one-on-one interactions in a laboratory setting. Activities included generation of microbubbles, safe handling of ozone, conducting food safety experiments with fresh produce. MS student-Kimberly Rankin defended her thesis in Fall 2022.MS student-Atul Walunj and Chen Zhu are scheduled to defend their thesis in October and November, 2023. PhD student-Brindhalakshmi Balasubramanian defended her dissertation in April 2024. PhD student-Trushenkumar Shah defended his dissertation proposal in Spring 2024 and is scheduled to defend his dissertation in Spring 2025. Professional development activities:Conducted conference presentations, workshops and seminar presentation to showcase the technology. Trained graduate students how to write a scientific abstract, present research at national and international conferences and write a manuscript. How have the results been disseminated to communities of interest? The results are being disseminated through conference presentations, posters, workshops and demonstrations of the technology. What do you plan to do during the next reporting period to accomplish the goals? During the next reporting period, we plan to complete the research objectives as per the timeline and publish our findings in peer-reviewed journals. In addition, we plan to conduct cost-benefit analysis of the technology and share the results with veteran, small and medium poultry farmers. In addition, a webinar will be conducted in participation with other sub-awards to present our research and reach a larger audience. The MS and PhD student thesis and dissertation will also be completed in the next reporting period.
Impacts
What was accomplished under these goals?
The accomplishments during the reporting period for each objective is provided below. Research: Objectives 1,2,3: The projects performed under objectives 1,2,3 are described below. The results of the research were presented at local, national and international conferences (please refer to the product section for details). Project 1:Balasubramanian, B., Allen, J., Zhu, C., Zhai, C., Upadhyay, A*. Ultrafine ozone bubble wash as an effective strategy to reduce Salmonella Enteritidis on shelled eggs. Poultry Science Association Annual Meeting, Louisville, KY, July 15-18, 2024. Introduction:SalmonellaEnteritidis (SE) is a significant cause of human foodborne illness, often transmitted through the consumption of contaminated eggs. Ozone, a Generally Recognized as Safe status gas has been widely used as an antimicrobial treatment against SE. Unlike chlorine-based compounds, ozone does not leave chemical residues on the product as it naturally degrades back to oxygen. However, its low solubility limits its application as an egg-wash treatment. This study investigated the efficacy of ultrafine bubbles technology in improving ozone solubility. Furthermore, the efficacy of ultrafine ozone bubbles (UFOB) as a dip treatment for reducing SE on shelled eggs was tested. Methods: UFOBs were produced using an ozone-injected-nanobubble generator system. The generated UFOB was characterized for size and concentration using Nanosight 300. The eggs were spot inoculated with 200µl of a 4-strain SE mixture (~ 9 log CFU/ml) and allowed to attach for 60 min at 25?. The inoculated eggs were dipped in sterile water (control) or water containing 200 mg/L of chlorine (industry control) or UFOB water for 1 and 5 min at 34?. Post-washing, the surviving SE on the eggs and wash water were enumerated on XLD agar. In addition, the efficacy of UFO on the egginstrumentalcolor(lightness, redness, and yellowness)was evaluated during refrigerated storage for 7 days. The study was completely randomized and repeated at least three times. Data was analyzed with two-way ANOVA in R version 4.3. Results: The UFOB number in water was approximately 10^8/ml with a size ranging from 100-200 nm. UFOB water had an oxidation potential of ~ 1200mV. The use of ultrafine bubble technology increased ozone solubility by at least threefold in water. The dissolved ozone concentration in UFOB water was ~ 8 mg/L at 25oC. In baseline (eggs not washed), ~ 6 log CFU/egg SE was recovered. Washing with water (control) reduced SE by ~ 2 log CFU/egg, however, UFO dip treatment completed inactivated SE to below detection limit (~ 4 log CFU/egg reduction) as early as 1 min of treatment (p<0.05). No pathogen was detected in the wash water of the UFOB treatment. UFOB treatment did not affect the color of the egg during storage (p>0.05). Significance: Results demonstrate that UFO bubble water could potentially be used as an antimicrobial wash in the egg industry. Experiments investigating the effect of UFOB on egg quality are currently underway. Project 2:Shah, T., Shah, C., Zhu, C., Zhai, C., Upadhyay, A*.Ultra-fine ozone bubbles: An effective chill tank treatment to reduceSalmonellaEnteritidis cross-contamination in poultry carcasses without affecting product color. IAFP Annual Meeting, Long Beach, CA. July 14-17, 2024. Introduction: The chill tank act as a source ofSalmonellaEnteritidis (SE) cross-contamination between poultry carcasses. Therefore, there is a need for developing effective intervention strategies for reducing SE cross-contamination in chill tank. This study investigated the efficacy of water containing Ultra-fine ozone bubbles (UFOB) in reducing cross-contamination ofSalmonellaEnteritidis on poultry carcasses. In addition, the effect of UFOB treatment on carcass color was studied. Methods: UFOB were produced in water maintained at 4oC using an ozone injected-nanobubble generator. The characteristics of UFOB and dissolved ozone levels were measured using NanoSight300 and ozone detection kit, respectively. Chicken skin (4 x 4 cm) was spot-inoculated with a 4-strain cocktail of SE (7 log CFU/sample) and allowed to attach for 120 min. One SE inoculated skin along with 9 non-inoculated skins were dipped in refrigerated DI water or UFOB water for 30 min. After treatment, surviving SE on chicken skin was enumerated on XLD agar. All experiments had duplicate samples, repeated thrice, and analyzed using student t-test (p<0.05). The color measurement was carried out using a chroma meter. Results: The dissolved ozone concentration in UFOB water was ~9 ppm. Bubble concentration was ~108/ml with size ~100-200 nm. Dipping of non-inoculated samples with inoculated sample in DI water resulted in 100% cross-contamination (10 samples positive out of 10). Dipping in UFOB water reduced cross-contamination by 50% (5 samples positive out of 10). SE load on skin treated with UFOB water reduced by ~1 log CFU/sample as compared to control. The UFOB water treatment did not affect the color of chicken skin. The effect of UFOB water dip on meat quality and consumer acceptability is currently underway. Significance: UFOB water could be used for reducing SE cross-contamination of poultry carcasses in chill tank without affecting the color parameters. Objective 4: This objective is currently underway. Extension: Objective 1:We disseminated the results of the project to rural veteran farmers through local conferences, workshops, electronic and printed materials, and demonstrations. A significant interest in the farming community has been observed. Major followup questions from farmers include the cost of using the equipment, operation time, total operational costs etc. These concerns will be addressed via our objective 4 of cost-benefit analysis of the technology in the coming year. Objective 2:We conducted technology demonstration to showcase the microbubble technology to farmers and extension educators. In the current year, we will conduct train the trainer programs for extension specialists and other interested stakeholders regarding the objectives and results of this project.
Publications
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2024
Citation:
Balasubramanian, B., Allen, J., Zhu, C., Zhai, C., Upadhyay, A*. Ultrafine ozone bubble wash as an effective strategy to reduce Salmonella Enteritidis on shelled eggs. Poultry Science Association Annual Meeting, Louisville, KY, July 15-18, 2024.
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2024
Citation:
Shah, T., Shah, C., Zhu, C., Zhai, C., Upadhyay, A*. Ultra-fine ozone bubbles: An effective chill tank treatment to reduce Salmonella Enteritidis cross-contamination in poultry carcasses without affecting product color. IAFP Annual Meeting, Long Beach, CA. July 14-17, 2024.
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Progress 07/01/22 to 06/30/23
Outputs
Target Audience:The target audience reached during this reporting period were academic scholars, farmers and food industry professionals. The primary means of communication was listserv and individual emails. Changes/Problems:
Nothing Reported
What opportunities for training and professional development has the project provided?Training activities: Mentored four graduate student (3 MS, 1 PhD program) through one-on-one interactions in a laboratory setting. Activities included generation of microbubbles, safe handling of ozone, conducting food safety experiments with fresh produce. MS student-Kimberly Rankin defended her thesis in Fall 2022. MS student-Atul Walunj and Chen Zhu are scheduled to defend their thesis in October and November, 2023. PhD student-Brindhalakshmi Balasubramanian defended her dissertation proposal defense on October 6th, 2023 and is scheduled to defend her dissertation in Spring, 2023. Professional development activities: Conducted conference presentations, workshops and seminar presentation to showcase the technology. Trained graduate students how to write a scientific abstract, present research at national and international conferences and write a manuscript.? How have the results been disseminated to communities of interest? The results are being disseminated through conference presentations, posters, workshops and demonstrations of the technology. What do you plan to do during the next reporting period to accomplish the goals? During the next reporting period, we plan to complete the research objectives as per the timeline and publish our findings in peer-reviewed journals. In addition, we plan to conduct cost-benefit analysis of the technology and share the results with veteran, small and medium poultry farmers. In addition, a webinar will be conducted in participation with other sub-awards to present our research and reach a larger audience. The MS and PhD student thesis and dissertation will also be completed in the next reporting period.?
Impacts
What was accomplished under these goals?
The accomplishments during the reporting period for each objective is provided below. Research: Objective 1,2,3: The projects performed under objective 1,2,3 are described below. The results of the research were presented at local, national and international conferences (please refer to the product section for details). Significant interest from the scientific community and farmers in using the microbubble technology was observed. Project 1: Efficacy of ultra-fine ozone bubbles in inactivating Listeria monocytogenes on fresh produce. Wash water used for fresh produce can act as a source of contamination due to the widespread distribution of food borne pathogens in the environment. Commercial disinfectants are not completely effective in killing pathogens on the surface of produce. The overall goal of this project was to develop novel washing treatments using ultra-fine Ozone (UFO) bubbles to reduce the survival of Listeria monocytogenes (LM) on fresh produce (lettuce, celery and apples). In addition, the effect of UFO bubbles on color of aforementioned produce was tested using Miniscan® XE. UFO bubbles were produced using an ozone injected-nanobubble generator system. The generated ozone nanobubble solution was characterized for size, concentration and oxidation potential. Thereafter, the antimicrobial efficacy of washing (for 1, 3, or 5 min at 25 or 4?) with water containing UFO bubbles against LM on fresh produce was investigated. Experiments had triplicate samples, repeated twice, and analyzed using ANOVA. Bubble characterization results indicated that the bubble number in water was approximately 10^8/ml with size < 200nm. The dissolved ozone concentration in UFO bubble water was ~5ppm at 25oC. Washing of fresh produce with ultra-fine ozone bubble water significantly reduced L. monocytogenes load by ~1- 1.5 log CFU/sample, as early as 1 min of treatment time (P<0.05). No significant increase in efficacy against L. monocytogenes on fresh produce was observed by increasing the wash time to 5 min (P>0.05). The wash treatment did not affect the color parameters (L, a, b values) of the fresh produce (P>0.05). No L. monocytogenes was detected in wash water (> 5 log CFU/ml reduction). Experiments investigating the efficacy of UFO bubble water in reducing the survival of S. enterica and E. coli O157:H7 on fresh produce are currently underway. UFO bubble water could be used for produce decontamination without affecting the color of the product. Project 2: Effect of Ultra-fine ozone bubbles in inactivating Listeria monocytogenes and Salmonella Enteritidis on Romaine lettuce. The widespread distribution of Salmonella Enteritidis and Listeria monocytogenes in agricultural environments such as manure, soil and irrigation water results in frequent contamination of fresh produce. Water used for produce washing can act as a source of contamination. Since this could lead to human infections, controlling Salmonella and L. monocytogenes in wash water and surface of fresh produce is critical for food safety. Currently used commercial disinfectants are not completely effective in killing the aforementioned pathogens on the surface of produce, especially in the presence of organic load. Therefore, there is a need for developing novel strategies that could be employed to control foodborne pathogens in wash water and on surface of fresh produce. The overall goal of this project was to develop novel washing treatments using ultra- fine bubble technology in combination with ozone to reduce the survival of Salmonella and L. monocytogenes on fresh produce (Romaine lettuce) and in wash water. Ultra-fine ozone (UFO) bubbles were produced using an ozone generator- nanobubble generator dual system. The UFO bubbles in water were characterized for size and number. Bubble characterization results indicated that the bubble number in water was approximately 10^8/ml with size ranging from 90-150 nm. The dissolved ozone concentration in UFO bubble water was ~ 5 ppm at 25oC. Washing of Romaine lettuce with ultra- fine ozone bubble water significantly reduced L. monocytogenes load by ~ 1.5 log CFU/sample, as early as 1 min of treatment time (P<0.05). No significant increase in efficacy against L. monocytogenes on lettuce was observed by increasing the wash time to 5 min (P>0.05). The wash treatment did not affect the color parameters (L, a, b values) of lettuce (P>0.05). No L. monocytogenes was detected in wash water (> 5 log CFU/ml reduction). Experiments investigating the efficacy of UFO bubble water in reducing the survival of S. Enteritidis on Romaine lettuce are currently underway. Objective 4: This objective will be performed during the current reporting period. Extension: Objective 1. We disseminated the results of the project to rural veteran farmers through local conferences, workshops, electronic and printed materials, and demonstrations. A significant interest in the farming community has been observed. Major followup questions from farmers include the cost of using the equipment, operation time, total operational costs etc. These concerns will be addressed via our objective 4 of cost-benefit analysis of the technology in the coming year. Objective 2: We conducted technology demonstration to showcase the microbubble technology to farmers and extension educators. In the current year, we will conduct train the trainer programs for extension specialists and other interested stakeholders regarding the objectives and results of this project.
Publications
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2022
Citation:
Balasubramanian, B., Trushenkumar S., Chen, Z., Rankin, K., Ghimire, S., Upadhyaya, I., Upadhyay, A. Effect of ultra-fine ozone bubbles in inactivating Listeria monocytogenes and Salmonella Enteritidis on Romaine lettuce. Poster #2022-01. New England Vegetable and Fruit Conference, Manchester, NH. December 13-15, 2022.
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2023
Citation:
A. Upadhyay. Demonstration on Ozone microbubble for produce safety. UConn Extension Vegetable and Small Fruit Growers's Conference. Rocky Hill, CT. January 4, 2023.
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2023
Citation:
Balasubramanian, B., Trushenkumar S., Chen, Z., Rankin, K., Ghimire, S., Upadhyaya, I., Upadhyay, A. Ultra-fine ozone bubbles inactivate Listeria monocytogenes on Romaine lettuce without affecting produce color.ASHS Annual Conference, Orlando, Florida, July 31-August 4, 2023.
- Type:
Journal Articles
Status:
Accepted
Year Published:
2023
Citation:
Balasubramanian, B., Xue, J., Luo, Y., Upadhyay, A. 2023. Eugenol nanoemulsion reduces Listeria monocytogenes biofilm by modulating motility, quorum sensing and biofilm architecture. Frontiers in Sustainable Food Systems Agro-Food Safety. DOI: 10.3389/fsufs.2023.1272373
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2023
Citation:
Walunj. A., Shah, T., Shah, C., Zhu, C., Rodrigues, A.L., Allen, J., Balasubramanian, B., Upadhyay, A. 2023. Effect of ultra-fine oxygen bubble water on production performance and jejunal proteome of broiler chickens. Poultry Science Association Annual Conference, Philadelphia, Pennsylvania, July 10-13, 2023.
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2023
Citation:
Balasubramanian, B., Trushenkumar S., Chen, Z., Rankin, K., Upadhyay, A. Efficacy of ultra-fine ozone bubbles in inactivating Listeria monocytogenes on fresh produce. International Association of Food Protection Annual Meeting, Toronto, Canada, July 16-19, 2023.
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2023
Citation:
Zhu, C., Rankin, K., Shah, C., Upadhyay, A. Eugenol nanoemulsion wash inactivates Listeria monocytogenes and Escherichia coli O157:H7 on Romaine lettuce in modified atmosphere packaging. Institute of Food Technologists Annual Meeting, Chicago, Illinois, July 16-19, 2023.
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Progress 07/01/21 to 06/30/22
Outputs
Target Audience: The target audience reached during this reporting period were academic scholars, farmers, poultry industry professionals, post-docs, graduate and undergraduate students. The primary means of communication was listserv, conference presentations, and individual emails. Changes/Problems:
Nothing Reported
What opportunities for training and professional development has the project provided?Training activities: Mentored twograduate student (MS, PhD program) through one-on-one interactions in a laboratory setting. Activities included generation of microbubbles, safe handling of ozone, conducting food safety experiments with fresh produce. Professional development activities:Conducted conference presentations, workshops and seminar presentation to showcase the technology. Trained graduate students how to write a scientific abstract, present research at national and international conferences and write a manuscript. How have the results been disseminated to communities of interest?The results are being disseminated through conference presentations, posters, workshops and demonstrations of the technology. What do you plan to do during the next reporting period to accomplish the goals?During the next reporting period, we plan to complete the research objectives as per the timeline and publish our findings in peer-reviewed journals. In addition, we plan to conduct cost-benefit analysis of the technology and share the results with veteran, small and medium poultry farmers. In addition, a webinar will be conducted in participation with other sub-awards to present our research and reach a larger audience. The MS and PhD student thesis and dissertation will also be completed in the next reporting period.
Impacts
What was accomplished under these goals?
The accomplishments during the reporting periodfor each objective is provided below. Research: Objective 1,2,3: The projects performed under objective 1,2,3 are described below. The results of the research were presented at local, national and international conferences (please refer to the product section for details). Significant interest from the scientific community and farmers in using the microbubble technology was observed. Project 1:Efficacy of ultra-fine ozone bubbles in inactivating Listeria monocytogenes on fresh produce. Wash water used for fresh produce can act as a source of contamination due to the widespread distribution of food borne pathogens in the environment. Commercial disinfectants are not completely effective in killing pathogens on the surface of produce. The overall goal of this project was to develop novel washing treatments using ultra-fine Ozone (UFO) bubbles to reduce the survival of Listeria monocytogenes (LM) on fresh produce (lettuce, celery and apples). In addition, the effect of UFO bubbles on color of aforementioned produce was tested using Miniscan® XE. UFO bubbles were produced using an ozone injected-nanobubble generator system. The generated ozone nanobubble solution was characterized for size, concentration and oxidation potential. Thereafter, the antimicrobial efficacy of washing (for 1, 3, or 5 min at 25 or 4?) with water containing UFO bubbles against LM on fresh produce was investigated. Experiments had triplicate samples, repeated twice, and analyzed using ANOVA. Bubble characterization results indicated that the bubble number in water was approximately 10^8/ml with size < 200nm. The dissolved ozone concentration in UFO bubble water was ~5ppm at 25oC. Washing of fresh produce with ultra-fine ozone bubble water significantly reduced L. monocytogenes load by ~1- 1.5 log CFU/sample, as early as 1 min of treatment time (P<0.05). No significant increase in efficacy against L. monocytogenes on fresh produce was observed by increasing the wash time to 5 min (P>0.05). The wash treatment did not affect the color parameters (L, a, b values) of the fresh produce (P>0.05). No L. monocytogenes was detected in wash water (> 5 log CFU/ml reduction). Experiments investigating the efficacy of UFO bubble water in reducing the survival of S. enterica and E. coli O157:H7 on fresh produce are currently underway. UFO bubble water could be used for produce decontamination without affecting the color of the product. Project 2:Effect of Ultra-fine ozone bubbles in inactivating Listeria monocytogenes and Salmonella Enteritidis on Romaine lettuce. The widespread distribution of Salmonella Enteritidis and Listeria monocytogenes in agricultural environments such as manure, soil and irrigation water results in frequent contamination of fresh produce. Water used for produce washing can act as a source of contamination. Since this could lead to human infections, controlling Salmonella and L. monocytogenes in wash water and surface of fresh produce is critical for food safety. Currently used commercial disinfectants are not completely effective in killing the aforementioned pathogens on the surface of produce, especially in the presence of organic load. Therefore, there is a need for developing novel strategies that could be employed to control foodborne pathogens in wash water and on surface of fresh produce. The overall goal of this project was to develop novel washing treatments using ultra-fine bubble technology in combination with ozone to reduce the survival of Salmonella and L. monocytogenes on fresh produce (Romaine lettuce) and in wash water. Ultra-fine ozone (UFO) bubbles were produced using an ozone generator-nanobubble generator dual system. The UFO bubbles in water were characterized for size and number. Bubble characterization results indicated that the bubble number in water was approximately 10^8/ml with size ranging from 90-150 nm. The dissolved ozone concentration in UFO bubble water was ~ 5 ppm at 25oC. Washing of Romaine lettuce with ultra-fine ozone bubble water significantly reduced L. monocytogenes load by ~ 1.5 log CFU/sample, as early as 1 min of treatment time (P<0.05). No significant increase in efficacy against L. monocytogenes on lettuce was observed by increasing the wash time to 5 min (P>0.05). The wash treatment did not affect the color parameters (L, a, b values) of lettuce (P>0.05). No L. monocytogenes was detected in wash water (> 5 log CFU/ml reduction). Experiments investigating the efficacy of UFO bubble water in reducing the survival of S. Enteritidis on Romaine lettuce are currently underway. Objective 4: This objective will be performed during the current reporting period. Extension: Objective 1. We disseminated the results of the project to rural veteran farmers through local conferences, workshops, electronic and printed materials, and demonstrations. A significant interest in the farming community has been observed. Major follow up questions from farmers include the cost of using the equipment, operation time, total operational costs etc. These concerns will be addressed via our objective 4 of cost-benefit analysis of the technology in the coming year. Objective 2: We conducted technology demonstration to showcase the microbubble technology to farmers and extension educators.In the current year, we will conduct train the trainer programs for extension specialists and other interested stakeholders regarding the objectives and results of this project.
Publications
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2022
Citation:
Balasubramanian, B., Trushenkumar S., Chen, Z., Rankin, K., Ghimire, S., Upadhyaya, I., Upadhyay, A. Effect of ultra-fine ozone bubbles in inactivating Listeria monocytogenes and Salmonella Enteritidis on Romaine lettuce. Poster #2022-01. New England Vegetable and Fruit Conference, Manchester, NH. December 13-15, 2022.
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2023
Citation:
A. Upadhyay. Demonstration on Ozone microbubble for produce safety. UConn Extension Vegetable and Small Fruit Growers's Conference. Rocky Hill, CT. January 4, 2023.
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2023
Citation:
Balasubramanian, B., Trushenkumar S., Chen, Z., Rankin, K., Upadhyay, A. Efficacy of ultra-fine ozone bubbles in inactivating Listeria monocytogenes on fresh produce. International Association of Food Protection Annual Meeting, Toronto, Canada, July 16-19, 2023.
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2023
Citation:
Balasubramanian, B., Trushenkumar S., Chen, Z., Rankin, K., Ghimire, S., Upadhyaya, I., Upadhyay, A. Ultra-fine ozone bubbles inactivate Listeria monocytogenes on Romaine lettuce without affecting produce color.ASHS Annual Conference, Orlando, Florida, July 31-August 4, 2023.
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Progress 07/01/20 to 06/30/21
Outputs
Target Audience:The target audience reached during this reporting period were academic scholars and food industry professionals. The primary means of communication was listserv and individual emails. Changes/Problems:Due to the ongoing COVI-19 pandemic, there is often a delay in shipment of supplies required to conduct proposed experiments. To face this challenge, the PI has reached out to multiple vendors and is proactively ordering the supplies to conduct experiments in time. In addition, there are unexpected delays due to the graduate student or their immediate contacts getting exposed to COVID-19 virus which results in quarantine period and temporary halt in the experiments. The PI and the graduate student have received their COVID-19 vaccine and are back in the laboratory to proceed with the proposed experiments. What opportunities for training and professional development has the project provided?During the reporting period, the graduate student was trained in conducting research in food microbiology. Specifically, the student was engaged in the planning and design of UFO bubble generator and in conducting experiments. The student learned to generate ozone and ozone microbubbles in laboratory setting, quantify dissolved ozone, and study the effect of temperature, turbulence and other physical factors on ozone generation and solubility. How have the results been disseminated to communities of interest?The community of small and medium scale farmers have been informed about the project via communications through extension educators working for the state. As the Pi and Co-PIs generate more data, the results will be disseminated via pamphlets, extension articles, workshops and demonstrations. What do you plan to do during the next reporting period to accomplish the goals? Based on the results so far, the research plan during the next reporting period is as follows: 1-Investigate the efficacy of UFO bubbles in reducing Salmonella on eggs. 2-Investigate the efficacy of UFO bubbles in reducing Salmonella and C. jejuni on poultry carcass. 3-Investigate the efficacy of UFO bubbles in reducing Salmonella and E. coli O157:H7 on fresh produce.
Impacts
What was accomplished under these goals?
During this reporting, the PI collaborated with Acniti company (Japan) and Molear company (California) to conceptualize, design, and develop a portable, bench-top, ultrafine ozone (UFO) bubble generator. Next, the PI shared the design of the UFO bubble generator with his collaborators at University of Connecticut, University of Arkansas, USDA-ARS, Arkansas, Cal Poly Pomona, and Appalachian State University. The PI requested the collaborators to share the equipment information to medium and small-scale farmers in their region and collect questions from them on the project. The PI also hired a graduate student to work on the project. The PI and graduate student have standardized the on-site production of ozone and ozone microbubbles under various temperature and time combinations. In addition, the effect of ozone in inactivating Salmonella and E. coli O157:H7 in produce wash water was investigated. Specific details on the experiments and results are provided below. Project 1: Investigating the solubility and stability of ozone in water maintained at different temperatures. Since ozone is generated on-site, it is critical to study the impact of type of machine, liquid temperature, and bubble time on ozone solubility. Also, since ozone naturally disintegrates to oxygen, understanding the disintegration kinetics of ozone in liquid medium and the various factors that impact the rate of disintegration is important for developing recommendations for farmers. The solubility and stability of ozone in water maintained at different temperatures (25, 4?) was measured at different bubbling time (0, 5, 10, and 15 min). The ozone was generated using an ozone generator (Ivation; ozone generation rate of 600 mg/h) and bubbled in 500 ml of DI water using a micro bubble diffuser. The concentration of ozone was measured post-bubble time at 0, 5, 10, 15, 20, 40 and 60 min using the Vacu-vials kit (SAM, OZONE, CHEMetrics, I-2019). Results and Discussion: The temperature of the liquid had a significant effect on Ozone solubility. For example, approximately 1 ppm of dissolved ozone was observed in the water maintained at 4? after 15 min of bubbling time. However, when the water was maintained at 25?, the dissolved ozone level obtained after 15 min of bubbling time was ~ 0.5 ppm (~50% less solubility). The ozone disintegration time was also higher in water maintained at 25? than at 4?. After 60 min post-bubble time, the ozone level reduced by ~90% in water maintained at 25? whereas the ozone level reduced by ~30% in water maintained at 4? suggesting that ozone has a higher stability at lower temperature. Project 2: Effect of oxygen concentrator and corona discharge tubes on amount of ozone generation. The generation of ozone was investigated using VMUS-4 ozone generator with or without an oxygen concentrator as described above. Results and discussion: VMUS-4 produces ozone at the rate of 4 g/h from dry air and 10 g/h from oxygen concentrator. This ozone generation rate is significantly higher than Ivation generator due to double corona discharge tubes present in the VMUS-4. Use of oxygen concentrator facilitated in the production of ~5 ppm of ozone in 1500 ml of DI water maintained at 25? in 5 min. Without the oxygen concentrator, a maximum ozone concentration of ~1 ppm was observed in 5 min. These results suggest that in order to generate a higher ozone concentration in water, an ozone generator with a higher ozone output (g/h) is required. Moreover, an oxygen concentrator facilitates in generating higher level of dissolved ozone in solution. Project 3: Effect of water turbulence on degradation rate of dissolved ozone. Since washing of produce, especially in hydrocooling systems, involves circulating water, we investigated the effect of water turbulence on the stability of dissolved ozone. Method: Ozone gas was produced using the VMUS-4 generator and oxygen concentrator set up and bubbled in 750 ml of sterilized, deionized water maintained at 4? for 15 min. Initial ozone concentration was measured and the ozonated water was divided into 3 groups (control, treatment 1 and treatment 2). The water in treatment 1 was stirred with a magnetic stirrer for 15 min at 80 rpm while the water in treatment 2 was stirred for 15 min at 1150 rpm. Dissolved ozone levels were measured at 1, 5, 10, 15 min of stirring. Results and discussion: Stirring the ozonated water at 80 rpm for 10 and 15 min led to ~8% and 17% degradation of dissolved ozone, respectively. A higher stirring speed of 1150 rpm increased the degradation rate as compared to control. Approximately 31% and 69% of dissolved ozone degradation was observed when the ozonated water was stirred at 1150 rpm for 10 and 15 min, respectively. These results suggest that circulation or turbulence of water accelerates the degradation rate of ozone. Our next set of experiments will investigate the role of various circulation speeds (for example 250, 500, 750, 1000 rpm), water surface area, liquid temperature, presence of organic matter, hardness in water on the rate of ozone degradation. Project 4: Efficacy of ozone microbubbles in inactivating planktonic cells of Salmonella and E. coli O157:H7 in produce wash water. Rationale: Contaminated wash water can act as a source of cross-contamination between produce and can act as a medium to spread foodborne pathogens. Therefore, it is critical to test the effectiveness of antimicrobial wash treatments in reducing pathogen survival in wash water. Ozone was bubbled in 500 ml of DI water maintained at 4? for 15 min. After bubbling, ozonated DI water was inoculated with Salmonella or E. coli O157:H7 at ~6 log CFU/ml. The wash water was sampled at 1, 5, 10, 15, 30 min and the surviving pathogens were enumerated by dilution and plating on oxford agar plates followed by incubation at 37? for 48 hours. Ozone concentration was simultaneously measured at the aforementioned timepoints. The concentration of ozone at 1 min was ~ 0.74 ppm. The ozone level reduced to ~0.4 ppm by 30 min. Results and discussion: Ozone micro bubbles (dissolved ozone concentration ~ 0.74 ppm) inactivated Salmonella and E. coli O157:H7 to below detection limits (~5 log CFU/ml reduction) as early as 1 min of treatment time indicating that dissolved ozone is very effective in inactivating the aforementioned pathogens in wash water. Ongoing experiments are investigating the efficacy of ozone and UFO bubbles in inactivating Salmonella on eggs and Salmonella and E. coli O157:H7 on fresh produce.
Publications
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