Progress 05/01/22 to 04/30/23
Outputs
Target Audience:Egg washing and processing industries, plasma equipment manufacturers, food scientists, the general public, students, and researchers. Changes/Problems:It was difficult to obtain dye for cuticle from USA and UK. Hence, there was a delay in the procurement of this dye. What opportunities for training and professional development has the project provided?The project involved one graduate student, one research technician, three undergraduate students, and one post-doctoral researcher. The researchers are engaged in laboratory science and technology development. The student is provided with an opportunity for technical presentation during bimonthly research progress meetings and weekly laboratory meetings. The technology and research were presented to industry representatives from Rose Acre Farms and CALPIS AMERICA, INC. The graduate student was also invited at Drexel University and Illinois Institute of Chicago to enlighten students on plasma technology, egg washing methods, and safety of shell eggs. How have the results been disseminated to communities of interest?The students have presented posters at IAFP 2021, IFT 2022, IAFP 2022, NCSU Graduate Student Research Symposium 2022, NCSU Undergraduate Research Symposium. The graduate student was also invited to speak about this research at Drexel University and Illinois Institute of Technology in the Food Science Program. We have also published one article in Journal of Food Protection regarding PAW optimization and surrogate validation. PI of this project was invited to present results from this research at the University of Georgia (Virtual presentation. November 4th, 2021), The Ohio State University (Virtual presentation. Oct 5th, 2021), BASF Corporation (Virtual presentation. April 8th, 2021), and NCSU podcast. What do you plan to do during the next reporting period to accomplish the goals?-Evaluate the efficacy of PAW using non-pathogenic and pathogenic strains of Salmonella enterica on the surface of shell eggs using the bench top spray washer. -Compare the efficacy of PAW with commercial sanitizers such as chlorine and quaternary ammonia for surface inactivation of shell eggs using the spray washer. -Perform quality analysis of eggs post-treatment based on the optimized conditions for microbial inactivation.?
Impacts
What was accomplished under these goals?
A. Microbiology Studies: Processing conditions of plasma-activated water (PAW) were statistically optimized using response surface methodology (RSM). Two optimized conditions based on 3 processing parameters: volume of water, time for plasma activation, and the distance between the water surface and nozzle of the plasma jet were obtained for the inactivation of planktonic cells of avirulent Salmonella Typhimurium by PAW. The individual batches of each of the optimized conditions of PAW were consecutively mixed to determine the efficacy of large volumes (600 - 700 mL) of PAW. There was no significant difference in the inactivation of S. Typhimurium when mixed batches were compared with individual batches of PAW. Physicochemical characteristics such as pH and ORP remained unaffected due to mixing but there was a significant reduction in nitrite and nitrate values of PAW. The storage of large volumes of PAW at 40 - 46 °C for 25 min did not change the physicochemical properties and inactivation efficacy of PAW. A validation study using a cocktail from six pathogenic strains of Salmonella was performed to provide evidence for using S. Typhimurium as a surrogate for Salmonella for PAW disinfection. The large batches of PAW prepared from the two optimized conditions were used to treat planktonic cells of S. Typhimurium (avirulent strain) grown in tryptic soy broth versus grown in tryptic soy agar at two time points (t1 = 0 min after reaching 40-46 °C, t2 = 25 min after reaching 40-46°C). This organism can show different resistances to desiccation if grown on agar v/s broth. However, when treated with PAW no significant differences in microbial inactivation were noted between agar?grown and broth? grown inoculum at both the time points for the two optimized conditions. This suggests that PAW after short storage was able to successfully inactivate broth?grown or agar?grown cells of S. Typhimurium, with a minimum reduction of 5 log. Studies were performed to determine aerobic plate count (APC) on surfaces of caged and cage-free eggs from the farm. For caged eggs APC count was less than 2.3 log cfu/egg while for cage-free eggs APC count was 2.7 log cfu/egg (based on 3 replications) post hand washing under warm tap water for 30 s. Hence, we decided to continue studies on caged eggs which were also visibly less soiled than cage free. Preliminary studies were conducted to determine the diluent volume needed to harvest inoculated bacteria from the egg surface. No significant differences were seen in inoculum concentrations when eggs were massaged in 20 mL 0.2% buffered peptone water (BPW) v/s 100 mL BPW. Studies were also performed to determine soaking time of farm fresh eggs in 70% ethanol to eliminate the background microorganisms. One minute soaking time led to less than 1.3 log cfu/egg of background microorganisms that could grow on Tryptic Soy Agar. All egg experiments were then performed after washing the eggs under warm (40 - 46 °C) tap water for 15 s to remove the dirt followed by soaking egg in ethanol for 1 min. The eggs were allowed to dry near burner for 30 min after which they were ready to be inoculated. A benchtop spray washer for eggs was designed and constructed to mimic the commercial egg washing spray systems. The spray washer can accommodate 3 eggs and has a rolling mechanism to rotate the eggs. The temperature of water coming out of nozzle is adjusted to 40 - 46 °C to match the commercial washing temperatures. A sanitation validation study was performed using Klebsiella aerogenes (previously known as Enterobacter aerogenes) and 200 ppm free chlorine to verify the sanitation protocol of the food contact surfaces of the spray washer. Studies using spray washer and eggs inoculated with S. Typhimurium or K. aerogenes are being performed by changing various factors: Different washing solutions such as deionized water (DI), chlorine, and PAW, High and low nozzle pressures, washing solutions at room and warm temperatures (40 - 46 °C), various washing times (30 s - 3 min), and different egg inoculation methods (spot v/s immersion inoculation). So far, the spent water which is recirculated for egg washing in the spray washer does not show detectable surviving organisms in PAW and Chlorine solutions but there are surviving bacteria present in DI after recirculating through inoculated eggs. We are also testing to see if organisms attach differently on eggs by inoculating eggs at various stages - unwashed eggs, eggs hand washed under warm tap water (15 s) and eggs hand washed under tap water (15 s) followed by soaking in ethanol (60 s). These eggs are stored in a refrigerator for various times and analyzed for the concentration of microorganisms that can be harvested at each time. In addition, these inoculation stages are also being analyzed using SEM to understand the bacterial attachment on the surface of shell eggs due to their porous nature. B. Quality Studies Cuticle blue dye has been obtained from CALPIS AMERICA, INC. Protocols are now optimized for cuticle study using the dye to stain the cuticle. The store-bought eggs have lower cuticle coverage than fresh eggs based on colorimetric results pre and post-staining with the dye. We are now performing studies to analyze cuticle coverage post-PAW treatment. Cuticle is also being analyzed using SEM with top and cross-section views. A special metallic probe was constructed to determine eggshell strength using a texture analyzer for compression tests.
Publications
- Type:
Journal Articles
Status:
Published
Year Published:
2023
Citation:
Shah U, Wang Q, Kathariou S, Salvi D. Optimization of Plasma-activated Water and Validation of a Potential Surrogate for Salmonella for Future Egg Washing Processes. J Food Prot. 2023 Jan;86(1):100029. doi: 10.1016/j.jfp.2022.100029.
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2022
Citation:
Shah U. (Presenter), Jackson J., Wang Q., Kathariou S., Salvi D. (2022). Validation of Salmonella Typhimurium MHM112 as a Surrogate for Inactivation of Pathogenic Salmonella using Plasma-Activated Water. International Association for Food Protection Annual Meeting (Poster).
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2022
Citation:
Shah U. (Presenter), Wang Q., Kathariou S., Salvi D. (2022). Determination of disinfection efficacy of enhanced volumes of plasma-activated water for future scale-up. Institute of Food Technologists FIRST Annual Event and Expo (Poster).
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2022
Citation:
Shah U. (Presenter), Wang Q., Kathariou S., Salvi D. (2022). Plasma-activated Water as a Novel Sanitizer: Process Optimization for Inactivation of Salmonella Typhimurium. Graduate Student Research Symposium at North Carolina State University (Poster).
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2023
Citation:
Gilleland J., Shah U., Salvi D. (2023). Evaluate Various Stages of Inoculation on Shell Eggs and Role of Plasma Technology in Shell Egg Surface Sanitization. Undergraduate Research Symposium (Poster).
- Type:
Other
Status:
Published
Year Published:
2022
Citation:
Shah U.1st place in North Carolina Ag and Life Science (NCALS) Foundation Board Research Competition (2022)
- Type:
Other
Status:
Published
Year Published:
2022
Citation:
Shah U.3rd place in Infographics PackPics Competition by Graduate Student Association at NCSU (2022)
- Type:
Other
Status:
Published
Year Published:
2022
Citation:
Shah U., Ahuja M.Honorable mention for highly commended video at New Zealand Institute of Food Science and Technology on Sustainable Food System (2022)
- Type:
Other
Status:
Published
Year Published:
2022
Citation:
Shah U. Food Safety Needs in the Egg Industry, Illinois Institute of Technology, FDSN Seminar (2022)
- Type:
Other
Status:
Published
Year Published:
2022
Citation:
Shah U. Applications of cold plasma in food, Drexel University, Food Science Seminar (2022)
- Type:
Other
Status:
Published
Year Published:
2021
Citation:
Salvi D. (2021) Food Processing. Invited Speaker, RTP180 to present a TED-style talk at RTP 180: Food Science at Frontier RTP. September 16, 2021 www.pbs.org/video/dr-deepti-salvi-nc-state-food-science-8pzbbl/
- Type:
Other
Status:
Published
Year Published:
2021
Citation:
Salvi D. (2021). Research updates on cold plasma technology. University of Georgia, Athens. November 4, 2021
- Type:
Other
Status:
Published
Year Published:
2021
Citation:
Salvi D. (2021). Research updates on cold plasma technology. The Ohio State University. October 5, 2021
- Type:
Other
Status:
Published
Year Published:
2021
Citation:
Salvi D. (2021). Cool Tech Part II: Pressure and Plasma with Dr. Deepti Salvi. Wolfing Down Food Science. April, 2021. https://open.spotify.com/show/1Gqk6evevPU6TwaoVfFq5y
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Progress 05/01/21 to 04/30/22
Outputs
Target Audience:Egg washing and processing industries, plasma equipment manufacturers, food scientists, general public, students, researchers Changes/Problems:It was difficult to obtain dye for egg cuticle from USA and UK. Hence, there was a delay in the procurement of this dye. What opportunities for training and professional development has the project provided?The project has supported 1 graduate student, a research technician, and a post-doctoral researcher. The researchers are engaged in laboratory science and technology development. The student is provided with opportunitiesfor technical presentation during bimonthly research progress meetings and monthly laboratory meetings. The technology and research were presented to industry representatives from Rose Acre Farms, CALPIS AMERICA, INC.,and American Egg Board. How have the results been disseminated to communities of interest?The student has presented a poster at IAFP 2021 and will be presenting a poster at NCSU Graduate Student Research Symposium in April 2022, IAFP 2022, and IFT 2022. The student was also invited to speak about this research at Drexel University in the Food Science Program. PI of this project was invited to present results from this research at theUniversity of Georgia (Virtual presentation. November 4th, 2021), TheOhio State University (Virtual presentation. Oct 5th, 2021),BASF Corporation (Virtual presentation. April 8th, 2021), and NCSU podcast. What do you plan to do during the next reporting period to accomplish the goals?1. Evaluate the efficacy of PAW using non-pathogenic and pathogenic strains of Salmonella enterica on the surface of shell eggs using the bench top spray washer. 2. Compare the efficacy of PAW with commercial sanitizers such as chlorine and quaternary ammonia for surface inactivation of shell eggs using the spray washer. 3. Develop and optimize protocols for quality analysis of eggs post-treatment.
Impacts
What was accomplished under these goals?
Processing conditions of plasma-activated water (PAW) were statistically optimized using response surface methodology (RSM). Two optimized conditions were obtained for the inactivation of planktonic cells of avirulent Salmonella Typhimurium by PAW. All 3 processing parameters (volume of water, time for plasma activation, and the distance between the water surface and nozzle of the plasma jet) significantly affected the physicochemical characteristics of PAW. In addition, individual batches of each of the optimized conditions of PAW were consecutively mixed to determine the efficacy of large volumes (600 - 700 mL) of PAW. There was no significant difference in the inactivation of S. Typhimurium when mixed batches were compared with individual batches of PAW. Physicochemical characteristics such as pH and ORP remained unaffected due to mixing but there was a significant reduction in nitrite and nitrate values of PAW. The storage of large volumes of PAW at 40 - 46 oC for 25 min did not change the physicochemical properties and inactivation efficacy of PAW. A validation study using a cocktail from six pathogenic strains of Salmonella was performed to provide evidence for using S. Typhimurium as a surrogate for Salmonella for PAW disinfection. These findings can be useful for future research studies and in scaling up this technology for industrial applications. A benchtop spray washer for eggs was designed and constructed to mimic the commercial egg washing spray systems. A sanitation validation study was performed using Klebsiella aerogenes (previously known as Enterobacter aerogenes) and 200 ppm free chlorine to verify the sanitation protocol of the food contact surfaces of the spray washer. Studies are now being conducted by inoculating the eggs and using deionized water and PAW at 40 - 46 oC to wash eggs using the spray washer under a bio-safety cabinet. Preliminary studieswere performed on fresh eggs (unwashed, obtained directly from farm) to determine the background microbiota of eggs. Protocols were optimized to remove dirt from eggs and treat them with 70% alcohol before inoculation. Cuticle blue dye has been obtained from CALPIS AMERICA, INC. Protocols are now being designed and optimized to determine the cuticle coverage post-treatment. A special metallic probe is under construction to determine eggshell strength using a texture analyzer for compression tests.
Publications
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2021
Citation:
Shah, U., Wang, Q., Kathariou, S., Salvi, D. (2021). Optimization of Nonthermal Plasma-activated Water Processing Conditions for Inactivation of Salmonella Typhimurium. International Association for Food Protection (IAFP) Annual Meeting, virtual conference
- Type:
Conference Papers and Presentations
Status:
Accepted
Year Published:
2022
Citation:
Shah, U., Jackson, J., Wang, Q., Kathariou, S., Salvi, D. (2022). Validation of Salmonella Typhimurium MHM112 as a Surrogate for Inactivation of Pathogenic Salmonella using Plasma-Activated Water. International Association for Food Protection (IAFP) Annual Meeting, Pittsburgh.
- Type:
Conference Papers and Presentations
Status:
Accepted
Year Published:
2022
Citation:
Shah, U., Wang, Q., Kathariou, S., Salvi, D. (2022). Determination of disinfection efficacy of enhanced volumes of plasma-activated water for future scale-up.Institute of Food Technologists (IFT), Chicago.
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Progress 05/01/20 to 04/30/21
Outputs
Target Audience:Egg washing and processing industries, plasma equipment manufacturers, food scientists, general public, students, researchers. Changes/Problems:Due to the COVID-19 pandemic, there were some delays in experimental work and hiring. What opportunities for training and professional development has the project provided?The project has supported 1 graduate student, a research technician, a post-doctoral researcher. The researchers are engaged in laboratory science and technology development. The student is provided with an opportunity for technical presentation during bimonthly research progress meetings and monthly laboratory meetings. How have the results been disseminated to communities of interest?
Nothing Reported
What do you plan to do during the next reporting period to accomplish the goals?-Optimize the PAW to select the most suitable condition. -Optimize the benchtop spray washer for handling eggs at the desired washing temperatures. -Evaluate the efficacy of PAW using non-pathogenic and pathogenic strains of Salmonella enterica on shell eggs.
Impacts
What was accomplished under these goals?
A study is in progress to optimize processing conditions of plasma-activated water (PAW) for its inactivation efficiency against Salmonella Typhimurium using response surface methodology. The Box-Behnken design (BBD) was used with 3 factors: volume of water, time for plasma activation, and the distance between the water surface and nozzle of the plasma jet. The effects of these parameters on pH, electrical conductivity (EC), oxidation-reduction potential (ORP), nitrate, and nitrite concentration in PAW were statistically analyzed. A total of 15 BBD experiments were performed in duplicate to measure these responses. The microbial reduction of planktonic cells of S. Typhimurium incubated in PAW for 1 min and 3 min at 40 - 46 oC was analyzed for the 15 experiments. Statistical optimization is pending due to microbial data reaching the detection limit and methods are in progress to resolve this problem. A benchtop spray washer for eggs was designed and constructed to mimic the commercial egg washing spray systems. This spray washer will be used to run PAW and commercial sanitizers to evaluate the microbiology and quality characteristics. A preliminary study was performed on fresh eggs (unwashed, obtained directly from the farm) to determine the background microbiota of eggs.
Publications
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