Progress 05/01/23 to 04/30/24
Outputs
Target Audience:Egg washing and processing industries, plasma equipment manufacturers, food scientists, 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 procurement of this dye. However, the dye we received was small quantities than desired. Hence, new dye mixture Lissamine Green B and Tartrazine was evaluated for staining the cuticle on shell eggs. Comparable results were obtained when comparing chlorine treated eggs with farm fresh eggs using this dye and decision was made to use the new dye mixture for future cuticle evaluations. The potential surrogate validated for planktonic studies in the beginning of this project does not seem to be a reliable surrogate for egg washing with PAW. Due to this, no significant reduction is achieved so far on pathogenic strains of Salmonella inoculated on eggs. DI is unexpectedly showing to cause higher reduction than PAW for non-pathogenic strains on eggs using spraying mechanism of washing. Hence, we are considering exploring PAW generated from other plasma devices. In addition, PAW characteristics are changing after it runs through the spray nozzle. What opportunities for training and professional development has the project provided?1 Ph.D. student completed their candidacy, 4 undergraduate students, and 1 graduate students were trained on microbial challenge and quality studies of shell eggs. 1 undergraduate student assisted Ph.D. student for 3 semesters and will be a potential graduate student in our lab next semester onwards. 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. The undergraduate student presented his research at the University Level. How have the results been disseminated to communities of interest?The students and PI have presented posters at IAFP 2021, IFT 2022, IAFP 2022, NCSU Graduate Student Research Symposium 2022, NCSU Undergraduate Research Symposium 2023, Dubai International Food Safety Conference 2023, IFT-EFFoST International Nonthermal Processing Workshop 2023, Poultry Science Association Annual Meeting 2023. The students are selected to present posters at NCSU Undergraduate Research Symposium 2024, IAFP 2024, and IFT 2024. 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. We are in the process of submitting an article on the direct plasma treatment of shell eggs to the Poultry Science Journal. 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. Publication: Shah U., Wang Q., Kathariou S., Salvi D. (2023). Optimization of Plasma-activated Water and Validation of a Potential Surrogate forSalmonellafor Future Egg Washing Processes. Journal of Food Protection. What do you plan to do during the next reporting period to accomplish the goals?- Investigate other plasma equipment to determine the inactivation efficacy of PAW for pathogenic Salmonella using the pour and spray washer method. - Conduct life cycle analysis to evaluate the sustainability value of plasma and plasma-activated water compared to traditional sanitizers -Perform quality analysis of eggs post-treatment based on the results obtained for microbial inactivation.
Impacts
What was accomplished under these goals?
A. Microbiology Studies: Tests were performed to see if K. aerogenes 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). The recovery of K. aerogenes (5.5 - 6.5 log cfu/egg) was similar for inoculum at all 3 stages and after 24 h and 48 h storage in refrigerator. Eggs spot inoculated with K. aerogenes were spray washed with PAW, Chlorine, and DI for 1 min 30 s at 40 - 46 °C that led to a reduction of 4.1, 5.2, and >5.9 log respectively. There were no surviving bacteria in any of these spent solutions. It was unexpected for DI to show such high reduction. Hence, inoculation method was changed to immersion inoculation and yet DI showed a higher reduction than PAW with no surviving bacteria in spent solutions. Eggs were also spray washed with DI and PAW at room temperature and that led to 1.6 and 1.9 log reduction respectively. PAW generating conditions were also changed to obtain relatively lower pH (<2.6) and yet the reduction on egg did not increase to 5 log as observed for DI. However, a trend was observed that PAW when used at room temperature caused ~1 log lower reduction than when used at 40 - 46 °C Swabbing different areas in the spray washer system immediately after washing inoculated eggs did not show any growth. The entire spent water was also run through a membrane filter using vacuum pump and there were no colonies observed in spent DI or spent PAW. However, when spent PAW and spent DI were collected from each nozzle after using them for inoculated eggs, they both had surviving bacteria. To eliminate any issues from the spray washer system, a hand spray bottle was used to spray PAW or DI at 40 - 46 °C manually on the eggs with egg rotating on a roller. A 2 min treatment using this method caused >4.1 log and 1.2 log reduction for K. aerogenes and 3 and 1.6 log reduction for S. Typhimurium by DI and PAW respectively. PAW characteristics changed in the spray washer system which was verified by pH and EC measurements before pumping PAW in the spray washer and after collecting PAW from the nozzle. Eggs washed without recirculation by generating 8-9 liters of PAW or DI maintained at room temperature caused 2.5 log and 1.8 log reduction of S. Typhimurium by DI and PAW respectively. Due to unexpected results obtained from spraying mechanisms, we switched to immersion washing, tested reusability in immersion washing, and using plasma-activated hydrogen peroxide (P-H2O2). For all solutions, eggs were immersed in 150 mL solution and hand massaged for 3 min at 42 - 44 °C. The average S. Typhimurium reduction by PAW and 0.5% H2O2 was 2.9 log and DI caused 2.6 log reduction. All 3 treatments showed insignificant differences among each other for reduction on egg. However, 0.5% P-H2O2 showed significantly higher reduction of 4.2 log indicating that plasma activation of hydrogen peroxide played a role in modifying the composition of H2O2 for microbial inactivation. None of the spent solutions had surviving Salmonella (<0.5 log cfu/mL) except for DI. Reusing PAW and DI did not show significant difference in reduction of Salmonella on egg with 2.3 and 2.0 log reduction respectively. The reused spent PAW had surviving bacteria of 1.9 log cfu/mL which was significantly lower than reused spent DI solution of 2.9 log cu/mL surviving bacteria. We also tested pour method for washing where 60 mL of solution (42 - 44 °C) was poured over the egg while the egg is rotated using sanitized gloves ensuring the solution comes in contact with entire surface area of the egg. In this case, the S. Typhimurium (non-pathogenic) reduction between PAW and chlorine was insignificant leading to 2.5 log and 3.1 log respectively but was significantly higher than that of DI that caused 0.3 log reduction. Similar to immersion method, chlorine and PAW did not have any surviving Salmonella in spent solutions (<0.5 log cfu/mL) while DI spent solution had 2.9 log cfu/mL of surviving Salmonella. However, DI and PAW showed insignificant difference for reduction of K. aerogenes on egg of 1.2 and 1.7 log respectively and chlorine exhibited significantly higher reduction of 3.8 log. In addition, the spent solutions showed similar trend with 2.1 log cfu/mL surviving in DI and no surviving K. aerogenes in PAW and chlorine solutions. Pour method tested on eggs inoculated with 6-strain pathogenic Salmonella cocktail led to 0.6 log reduction by both PAW and DI and 4.3 log reduction by chlorine. Hence, S. Typhimurium may not be considered an appropriate surrogate for application of PAW on egg washing. Bacterial inactivation mechanism by PAW: PAW at 1 min caused injury to some cells at a concentration of 0.9 ± 0.8 log cfu/mL while PAW at 3 min did not cause any injury. The average fluorescent intensity for cell membrane damage by PAW was higher than that by DI but this difference was insignificant due to a higher standard deviation seen for DI treatments. This indicates both PAW and DI could have caused cell membrane damage in S. Typhimurium. PAW treated cells caused the highest lipid peroxidation on cell membrane and DI was also responsible for lipid peroxidation. However, this indicates mild heat alone does not cause extensive lipid peroxidation but when combined with PAW the reactive species may play a role in peroxidation. Direct plasma treatment of shell eggs: An increase in direct plasma treatment time from 1 min to 3 min increased reduction from 0.4 ± 0.8 to 2.2 ± 0.5 log for S. Typhimurium spot inoculated on shell eggs. Plasma treatment time of 3 min led to a 2.5 ± 1.1 log reduction of K. aerogenes. A hot air treatment did not cause inactivation greater than 0.7 ± 0.05 log cfu/egg for K. aerogenes and 0.3 ± 0.2 log cfu/egg for S. Typhimurium. It is evident that heat did not play a role in microbial inactivation. The UV treatment caused a reduction of 2.1 ± 1.0, 3.3 ± 0.1, and 3.7 ± 0.1 log of S. Typhimurium at treatment times of 0.25, 1.5, and 3 min respectively. A reduction of 5.1 ± 0.3 log in Salmonella was obtained after plasma (3 min) + UV (3 min) treatment used in sequence as a hurdle approach. B. Quality Studies Cuticle blue dye has been obtained from CALPIS AMERICA, INC. Protocols were 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. However, the quantity received for this cuticle dye was not sufficient to last for 3 years of the project. Hence, another protocol was optimized using new dye mixture of Lissamine Green B and Tartrazine for staining egg shells. A special metallic probe was constructed to determine eggshell strength using a texture analyzer for compression tests. Quality studies are now being conducted using pour method on shell egg washing with PAW and chlorine. Direct plasma treatment on shell eggs did not cause significant changes in color values but plasma + UV led to a significant increase in yellow color. There was no statistical difference in cuticle coverage between control, plasma, UV, and plasma + UV treatments. Various quality characteristics such as haugh unit, egg weight, yolk index, yolk pH, albumen pH, yolk color, and shell strength did not show major changes during the 6-week storage study after all the treatments.
Publications
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2023
Citation:
Gilleland J., Shah U., Salvi D.(2023). Microbial Inactivation by Atmospheric Pressure Plasma and Effects on Quality of Shell Eggs. NCSU Undergraduate Research Symposium (2024).
- Type:
Conference Papers and Presentations
Status:
Accepted
Year Published:
2024
Citation:
Shah U., Gilleland J., Salvi D. (2024). Effects of Cold Plasma and Ultraviolet (UV) on Microbial Inactivation and Quality Characteristics of Eggshells. Institute of Food Technologists FIRST Annual Event and Expo.
- Type:
Conference Papers and Presentations
Status:
Accepted
Year Published:
2024
Citation:
Shah U., Salvi D. (2024).Efficacy of Plasma-Activated Water in Cell Membrane Damage and Salmonella Inactivation in Egg Washing. International Association for Food Protection Annual Meeting.
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2023
Citation:
Shah U., Gilleland J., Salvi D. (2023). Evaluating the effectiveness of atmospheric pressure plasma treatment on microbial inactivation and quality effects on shell eggs. Dubai International Food Safety Conference.
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2023
Citation:
Shah U., Salvi D. (2023). Waterless Plasma Treatment for the Safety of Shell Eggs. Poultry Science Association Annual Meeting.
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2023
Citation:
Shah U., Salvi D. (2023). Waterless Plasma Treatment for the Safety of Shell Eggs. IFT-EFFoST International Nonthermal Processing Workshop.
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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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