Progress 02/10/11 to 02/09/16
Outputs
Progress Report Objectives (from AD-416): The overall goal of this research is to reduce the risk of foodborne illness associated with the consumption of produce and shell eggs. Effective postharvest intervention technologies for these foods have proven difficult to implement and, therefore, are on the FDA Center for Food Safety and Applied Nutrition's list of highest research priorities. This new project was formed to apply proven engineering expertise to the development of efficient intervention strategies for challenging foods such as shell eggs, fresh produce and frozen produce. While other projects continue looking at intervention methods such as hot water immersion, irradiation and cold plasma for these types of foods, the proposed project will research novel technologies including microwave, radio frequency, UV, and flash steam. The specific objectives of the research program are as follows: 1: Develop, evaluate, and validate through laboratory and pilot-plant processing the effect of single and combinations of intervention technologies on pathogen reduction in eggs. Specifically, conduct research to "pasteurize" shell eggs using technologies, such as microwave heating or ozone-based combination treatments. 2: Develop, evaluate, and validate through laboratory and pilot-plant processing the effect of single and combinations of intervention technologies on pathogen reduction in fresh produce. For example, engineer flash steam and UV treatments and develop antimicrobial/ antioxidant compounds of GRAS origin as a processing aid for fruits and vegetables. 2A: Develop and evaluate a hurdle approach to inactivate Salmonella spp. and E. coli O157:H7 from tomato stem scar tissue. Application of thermal energy to the stem scar region of the tomato will be employed for the destruction of pathogens and to expose bacteria to subsequent treatments including antimicrobial immersion. 2B: Develop and evaluate a novel approach to inactivate Salmonella and E. coli O157:H7 on berries by an antimicrobial water agitation treatment. Aerated turbulence and vacuum will be applied to berries in order to remove particulate matter and expose niches within the host tissue to antimicrobials. 2C: Develop and evaluate a hurdle approach to inactivate Salmonella spp., L. monocytogenes and E. coli O157:H7 on fresh fruits and vegetables using individual treatments or a combination of antimicrobials and flash steam. 3: Develop, evaluate, and validate through laboratory and pilot-plant processing the effect of single and combinations of intervention technologies on pathogen reduction for frozen fruits and vegetables. Currently some vegetables are processed through snap freezing. It might be possible to develop a steam pasteurization processing technology that would allow vegetables to be stored refrigerated instead of frozen while having a stable shelf life. Approach (from AD-416): Radio frequency (RF) heating intervention technology will be developed that requires less time to pasteurize shell eggs than hot water immersion. A 4 kW RF unit will be modified to enable the application of RF energy to a shell egg. Another option to improve heating uniformity is to immerse the shell eggs in a liquid while applying RF energy. In addition, nonthermal ozone treatment of shell eggs will be evaluated for reducing Salmonella. Combinations of these technologies, such as ozone and RF, will be investigated. Shell eggs will be sent to Dr. Deana Jones (Athens, GA) for extensive quality tests including foaming ability, Haugh unit, yolk index, as well as turbidity and viscosity of the egg white. Tomatoes will be inoculated and the current practice of trimming stem-scar tissue will be tested to determine if subsequent cross-contamination of tomatoes occurs during traditional stem-scar removal. Vacuum perfusion sanitization will be used in combination with chemical sanitizers for the decontamination of Salmonella and E. coli from tomatoes. A novel localized heat treatment for the physical inactivation of Salmonella within the stem scar of tomatoes will be developed. Our engineers will modify existing technology currently used for the electrical thermal dehorning of sheep, goats and cattle. Berries will be inoculated and a hurdle approach to decontaminating berries will be applied by the use of sanitizers in combination with physical treatments such as applied vacuum perfusion, or aerated turbulence of water. Fruit (including melon, apple, tomato, pepper, mango, cucumber, and pear) surfaces will be inoculated and a novel antimicrobial treatment will be developed that will not impact the sensorial quality. The kinetics and mechanism of inactivation of the developed antimicrobial wash solutions will be investigated. Flash steam technology will be used to inactivate bacteria on such fruits and vegetables as peppers, cantaloupes, mangoes, green onions, parsley, cabbage, cucumbers, and radishes. The produce will be evaluated for thermal and mechanical damage using a texture analyzer and colorimeter. Frozen fruit (e.g., berries) and vegetables (e.g., corn and peas) will be inoculated and GRAS antimicrobial compounds will be used to sensitize foodborne pathogens to UV light inactivation and inhibit growth of pathogens on thawed fruits and vegetables. The bacterial inactivation using pulsed UV bulbs, that provide higher intensities than 254 nm UV bulbs, will be investigated. The latest technology to emerge is UV-LED (light-emitting diode). UV-LEDs are compact, do not fail as quickly as other types of UV bulbs, and have a potential for significant energy savings. A radio frequency process (RFP) was developed to rapidly pasteurize shell eggs. It works by using penetrating radio frequency (RF) energy to quickly heat the yolk, which is the egg component most favorable to harboring Salmonella. As the egg is rotated, RF energy and cooling water are simultaneously applied to the egg. This initiates pasteurization of the yolk while maintaining a low temperature in the heat-sensitive egg white, thus preventing hazing. Immediately after the RF heating process, the egg is placed in hot water to pasteurize the egg white and to complete pasteurization of the yolk. Radio frequency pasteurization of shell eggs, invented by ARS engineers in Wyndmoor, Pennsylvania, was granted patent rights (U.S. 8,973,492). The process inactivates 99.999% of Salmonella (inoculated) in shell eggs in 1/3 the time of the conventional hot water process and results in eggs that retain their fresh-like appearance and significantly more functionality. Substantial progress was made in scaling up the process. A prototype RFP unit was assembled and tested that can process four eggs simultaneously. Work is ongoing to maximize processing uniformity of the eggs. In addition, a larger RFP unit is being assembled in collaboration with a funded-CRADA industry partner. In produce-related research, ARS scientists in Wyndmoor, Pennsylvania evaluated the washing of tomatoes with 63 sanitizers. Some of the sanitizers achieved an inactivation of 99.999% of Salmonella. A new organic antimicrobial wash was developed in partnership with a funded- CRADA industry partner. The results showed that the new formulation kills up to 99.97% of inoculated pathogens on grape tomatoes and apples, and up to 99.0% percent on spinach and cantaloupe rind. The formulation received a non-objection letter from Health Canada as well as approval from the FDA for use as an antimicrobial produce wash and was also approved as USDA Certified Organic (OMRI). A patent on the produce wash has been filed. Low level concentrations of the produce wash (0.2, 0.3, and 0.4%) inactivated greater than 99.999% of Listeria, Salmonella and E. coli. In the presence of an interference substance (5 percent apple juice), reductions for 0.5 and 0.4% concentrations of the produce wash, respectively, were E. coli (6.25, 5.06), Salmonella (6.78, 6.18), and Listeria (6.69, 2.94). A second antimicrobial wash solution was independently developed by ARS researchers in Wyndmoor, Pennsylvania that reduces Salmonella, E. coli O157:H7 and Listeria monocytogenes on produce surfaces. All ingredients used in making the wash are considered generally recognized as safe (GRAS). Inactivation using this wash solution achieved 99.99% kill and prevented transfer of these pathogens to the interior flesh during fresh-cut preparation. This antimicrobial solution was also shown to reduce the browning reaction on fresh-cut apples and pears. An invention disclosure for a patent application for the wash was submitted. The effect of quick freezing on bacterial populations inoculated on baby spinach and in combination with the wash was investigated. Baby spinach treated with the wash and then frozen at - 80 C for 1 h reduced the human bacterial populations to below detection, while even native spinach microflora was reduced by 99.9%. A wet steam intervention treatment was also developed that kills human bacterial pathogens on cantaloupe surfaces and reduces transfer to fresh-cut cantaloupe. The wet steam process did not affect sensory characteristics of the fresh-cut melons. In addition, combining ultraviolet-C (UV-C) light treatment with antimicrobials to inactivate Salmonella Enterica on plum tomatoes was investigated. The combined UV-C and antimicrobial treatment effectively inactivated Salmonella on tomatoes during storage. The combination treatment did not affect the tomatoes� firmness and color during storage. The feasibility of inactivating bacteria using UV energy supplied by light emitting diodes (UV-LED) was investigated. UV-LEDs have only very recently become commercially available. Compared to conventional UV mercury bulbs, UV-LED bulbs may be more energy efficient as well as more environmentally friendly. Using an experimental system that was designed and assembled in-house, E. coli inoculated onto the surface of a tomato was reduced by 99.7 percent after 150 seconds of UV- LED exposure. In other research, in order to mitigate transfer of bacterial pathogens from soil to fresh produce, studies examined the effects of mycorrhizal fungi as well as a biofuel production byproduct (pyrolysis biochar) on bacterial survival in soil. Long-term shelf stability of whey protein during adverse storage conditions was established and efficacy was found to be dependent on packaging, temperature and humidity. Accomplishments 01 Radio frequency pasteurization of shell eggs scaled-up. Radio frequency pasteurization (RFP) produces safer eggs with exceptional quality; however, larger scale equipment is needed to make the process economical. Based on the ARS-patented RFP prototype (U.S. 8,973,492), which is capable of killing 99.999% of Salmonella, ARS engineers in Wyndmoor, Pennsylvania designed and built a RFP unit that can simultaneously process four eggs. A larger scale RFP unit is being assembled, in collaboration with a CRADA industry partner, which will facilitate commercialization of RFP. 02 Antimicrobial produce wash receives FDA approval. A patent-pending produce wash was developed jointly with a CRADA industry partner and ARS researchers in Wyndmoor, Pennsylvania. This antimicrobial solution has been shown to inactivate foodborne pathogens on produce and in wash waters which assists in preventing cross contamination of fruits and vegetables during washing. Besides being approved for use in Canada and receiving USDA-Organic Materials Review Institute Certified-Organic Status, the FDA recently approved the produce wash to be used on fresh and fresh cut fruits and vegetables. This approval by the FDA has allowed the industry cooperator to begin selling the product to fresh produce processors.
Impacts
(N/A)
Publications
- Geveke, D.J., Gurtler, J., Jones, D.R., Bigley, A.R. 2016. Inactivation of salmonella in shell eggs by hot water immersion and its effect on quality. Journal of Food Science. 81(3):M709-M714.
- Miks-Krajnik, M., Yoon, Y., Ukuku, D.O., Yuk, H. 2016. Growth dynamics of specific spoilage organisms and associated spoilage biomarkers in chicken breast stored aerobically. Food Microbiology and Safety Journal. DOI:10. 1111/1750-3841.13371.
- Ukuku, D.O., Mukhopadhyay, S., Geveke, D.J., Olanya, O.M., Niemira, B.A. 2016. Minimal thermal treatments for reducing bacterial population on cantaloupe rind surfaces and transfer to fresh-cut pieces. Journal of Food Protection. DOI:10.4315/0362-028X.JFP-16-046.
- Krajnik, M., Yoon, Y., Ukuku, D.O., Hyun, G. 2016. Volatile chemical spoilage indexes of raw Atlantic salmon (salmo salar)stored under aerobic condition in relation to microbiological and sensory shelf lives. Food Microbiology. 53:182-191.
- Ukuku, D.O., Onwulata, C.I., Mukhopadhyay, S., Thomas-Gahring, A.E., Chau, L.I., Tunick, M.H. 2016. Changes in microbial populations of WPC34 and WPC80 whey protein during long term storage. Journal of Food Processing and Preservation. doi: 10/1111/jfpp.12743.
- Geveke, D.J., Aubuchon, I., Zhang, H.Q., Boyd, G., Sites, J.E., Bigley, A. 2015. Validation of a pulsed electric field process to pasteurize strawberry puree. Journal of Food Engineering. 166:384-389.
- Geveke, D.J., Trujillo, F. 2014. Nonthermal processing by radio frequency electric fields. Book Chapter. Sun, D.W, editor. Emerging Technologies for Food Processing 2nd Edition. Amsterdam:Elsevier Academic Press. p. 259-269.
- Ukuku, D.O., Geveke, D.J., Chau, L.I., Niemira, B.A. 2016. Microbial safety and overall quality of cantaloupe fresh-cut pieces prepared from whole fruit after wet steam treatment. International Journal of Food Microbiology. doi: 10.1016/j.ijfoodmicro.2016.05.019.
- Ojwang, D.J., Nyankanga, R.O., Olanya, O.M., Ukuku, D.O., Imungi, J. 2016. Yield potential of pigeon pea cultivars. Subtropical Agriculture and Environments. 67:1-12.
- Ukuku, D.O., Latiful, B., Kassama, L.S., Mukhopadhyay, S., Olanya, O.M. 2015. Survival, injury and inactivation of human bacterial pathogens in foods: effect of non-thermal treatments. Book Chapter. p. 82-96.
- Ukuku, D.O., Latiful, B. 2015. Foodborne illness and microbial agents. Book Chapter. Foodborne Pathogens and Safety (Food Biology Series);Bari,Md. L.,Ukuku, Dike (editors) CRC Press, Taylor and Francis Group.Boca Raton, Florida, USA. p. 16-34.
- Ukuku, D.O., Mukhopadhyay, S., Juneja, V.K., Rajkowski, K.T. 2014. Evaluating natural antimicrobials for food application, in natural antimicrobials for food safety and quality. Book Chapter. Oxford, UK: Woodhead Publishing. p. 185-202.
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Progress 10/01/14 to 09/30/15
Outputs
Progress Report Objectives (from AD-416): The overall goal of this research is to reduce the risk of foodborne illness associated with the consumption of produce and shell eggs. Effective postharvest intervention technologies for these foods have proven difficult to implement and, therefore, are on the FDA Center for Food Safety and Applied Nutrition's list of highest research priorities. This new project was formed to apply proven engineering expertise to the development of efficient intervention strategies for challenging foods such as shell eggs, fresh produce and frozen produce. While other projects continue looking at intervention methods such as hot water immersion, irradiation and cold plasma for these types of foods, the proposed project will research novel technologies including microwave, radio frequency, UV, and flash steam. The specific objectives of the research program are as follows: 1: Develop, evaluate, and validate through laboratory and pilot-plant processing the effect of single and combinations of intervention technologies on pathogen reduction in eggs. Specifically, conduct research to "pasteurize" shell eggs using technologies, such as microwave heating or ozone-based combination treatments. 2: Develop, evaluate, and validate through laboratory and pilot-plant processing the effect of single and combinations of intervention technologies on pathogen reduction in fresh produce. For example, engineer flash steam and UV treatments and develop antimicrobial/ antioxidant compounds of GRAS origin as a processing aid for fruits and vegetables. 2A: Develop and evaluate a hurdle approach to inactivate Salmonella spp. and E. coli O157:H7 from tomato stem scar tissue. Application of thermal energy to the stem scar region of the tomato will be employed for the destruction of pathogens and to expose bacteria to subsequent treatments including antimicrobial immersion. 2B: Develop and evaluate a novel approach to inactivate Salmonella and E. coli O157:H7 on berries by an antimicrobial water agitation treatment. Aerated turbulence and vacuum will be applied to berries in order to remove particulate matter and expose niches within the host tissue to antimicrobials. 2C: Develop and evaluate a hurdle approach to inactivate Salmonella spp., L. monocytogenes and E. coli O157:H7 on fresh fruits and vegetables using individual treatments or a combination of antimicrobials and flash steam. 3: Develop, evaluate, and validate through laboratory and pilot-plant processing the effect of single and combinations of intervention technologies on pathogen reduction for frozen fruits and vegetables. Currently some vegetables are processed through snap freezing. It might be possible to develop a steam pasteurization processing technology that would allow vegetables to be stored refrigerated instead of frozen while having a stable shelf life. Approach (from AD-416): Radio frequency (RF) heating intervention technology will be developed that requires less time to pasteurize shell eggs than hot water immersion. A 4 kW RF unit will be modified to enable the application of RF energy to a shell egg. Another option to improve heating uniformity is to immerse the shell eggs in a liquid while applying RF energy. In addition, nonthermal ozone treatment of shell eggs will be evaluated for reducing Salmonella. Combinations of these technologies, such as ozone and RF, will be investigated. Shell eggs will be sent to Dr. Deana Jones (Athens, GA) for extensive quality tests including foaming ability, Haugh unit, yolk index, as well as turbidity and viscosity of the egg white. Tomatoes will be inoculated and the current practice of trimming stem-scar tissue will be tested to determine if subsequent cross-contamination of tomatoes occurs during traditional stem-scar removal. Vacuum perfusion sanitization will be used in combination with chemical sanitizers for the decontamination of Salmonella and E. coli from tomatoes. A novel localized heat treatment for the physical inactivation of Salmonella within the stem scar of tomatoes will be developed. Our engineers will modify existing technology currently used for the electrical thermal dehorning of sheep, goats and cattle. Berries will be inoculated and a hurdle approach to decontaminating berries will be applied by the use of sanitizers in combination with physical treatments such as applied vacuum perfusion, or aerated turbulence of water. Fruit (including melon, apple, tomato, pepper, mango, cucumber, and pear) surfaces will be inoculated and a novel antimicrobial treatment will be developed that will not impact the sensorial quality. The kinetics and mechanism of inactivation of the developed antimicrobial wash solutions will be investigated. Flash steam technology will be used to inactivate bacteria on such fruits and vegetables as peppers, cantaloupes, mangoes, green onions, parsley, cabbage, cucumbers, and radishes. The produce will be evaluated for thermal and mechanical damage using a texture analyzer and colorimeter. Frozen fruit (e.g., berries) and vegetables (e.g., corn and peas) will be inoculated and GRAS antimicrobial compounds will be used to sensitize foodborne pathogens to UV light inactivation and inhibit growth of pathogens on thawed fruits and vegetables. The bacterial inactivation using pulsed UV bulbs, that provide higher intensities than 254 nm UV bulbs, will be investigated. The latest technology to emerge is UV-LED (light-emitting diode). UV-LEDs are compact, do not fail as quickly as other types of UV bulbs, and have a potential for significant energy savings. Radio frequency pasteurization (RFP) of shell eggs, invented by ARS engineers at Wyndmoor Pennsylvania, was recently granted patent rights (U. S. 8,973,492). The process inactivates 99.999% of Salmonella (inoculated) in shell eggs in 1/3 the time of the conventional hot water process and results in a significantly superior quality egg. Substantial progress was made in scaling up the process in collaboration with a funded-CRADA industry partner. A prototype RFP unit was assembled and tested that can process multiple eggs simultaneously. Work is ongoing to maximize processing uniformity of the eggs. In addition, an even larger RFP unit is being designed. Recently, a postdoc researcher was appointed to evaluate the quality of the RFP eggs. In produce-related research, a new organic antimicrobial wash was developed in partnership with a funded- CRADA industry partner. The results showed that the formulation kills up to 99.97 percent of inoculated pathogens on grape tomatoes and apples, and up to 99.0 percent on spinach and cantaloupe rind. The new formulation received a non-objection letter from Health Canada for use as an antimicrobial produce wash. The formulation was also approved as USDA Certified Organic (OMRI). In other research, a thermal cauterization technique was able to inactivate greater than 99.999 percent of Salmonella from tomato stem scars; however, a sonication wash technique only inactivated 68 percent of Salmonella on strawberries. Viral inactivation experiments were also run, analyzing Tulane virus as a useful surrogate for cold plasma treatment in comparison to Murine Norovirus. A second antimicrobial wash solution, named Lovit, independently was developed that reduces Salmonella, E. coli O157:H7 and Listeria monocytogenes on produce surfaces. Inactivation using this wash solution achieved 99.99% kill and prevented transfer of these pathogens to the interior flesh during fresh-cut preparation. This antimicrobial solution was also shown to reduce the browning reaction on fresh-cut apples and pears. A wet steam intervention treatment was also developed that kills human bacterial pathogens on cantaloupe surfaces and reduces transfer to fresh-cut pieces. The wet steam process did not affect sensorial characteristics of the fresh-cut melons. In addition, combining ultraviolet-C (UV-C) light treatment with antimicrobials to inactivate Salmonella Enterica on plum tomatoes was investigated. The combined UV-C and antimicrobial treatment effectively inactivated Salmonella on tomatoes during storage at 4 deg C. The combination treatment did not affect the tomatoes� firmness and color during storage. Accomplishments 01 Radio frequency process to pasteurize shell eggs is scaled-up. Radio frequency pasteurization (RFP) produces safer eggs with exceptional quality; however, larger scale equipment is needed to process more eggs. Based on the ARS-patented RFP prototype (U.S. 8,973,492) which is capable of killing 99.999% of Salmonella, ARS engineers at Wyndmoor, Pennsylvania, designed and built a RFP unit that can simultaneously pasteurize multiple eggs. The multiple egg unit is being used to design an even larger unit in order to facilitate commercialization of RFP. Pasteurization of all shell eggs in the U.S. would reduce cases of Salmonella illnesses by an estimated 110,000 annually. 02 Antimicrobial wash solution developed for fresh and fresh-cut produce. A produce wash solution, called Lovit, was developed by ARS Researchers at Wyndmoor, Pennsylvania. The novel wash inactivates 99.99% of human bacterial pathogens on produce surfaces and minimizes transfer of these pathogens to the interior during fresh-cut preparation. It also slows down the browning reaction on fresh-cut apples and pears. All ingredients used in making the wash are considered generally recognized as safe (GRAS). A patent application has been filed and a company has filed for licensing. This innovation is the basis of a forthcoming article in AgResearch Magazine.
Impacts
(N/A)
Publications
- Olanya, O.M., Taylor, J., Ukuku, D.O., Malik, N.S. 2014. Inactivation of Salmonella serovars by Pseudomonas chlororaphis and Pseudomonas fluorescens strains on tomatoes. Biocontrol Science and Technology. 25(4) :399-413. DOI:10.1080/09583157.2014.982513.
- Gurtler, J., Bailey, R., Jin, Z.T., Fan, X. 2014. Inactivation of an E. coli 0157:H7 and Salmonella composite on fresh strawberries by varying antimicrobial washes and vacuum perfusion. International Journal of Food Microbiology. 139:113-118.
- Nicholoson, A.M., Gurtler, J., Bailey, R., Niemira, B.A., Douds, D.D. 2015. Influence of mycorrhizal fungi on fate of E. coli 0157:H7 in soil and Salmonella in soil and internalization into romaine lettuce plants. International Journal of Food Microbiology. 192:95-102.
- Gurtler, J., Bailey, R., Cray, W.C., Hinton Jr, A., Meinersmann, R.J., Ball, T.A., Jin, Z.T. 2015. Salmonella spp. isolated from ready-to-eat pasteurized liquid egg produce: thermal resistance, biochemical profile, and fatty acid analysis. International Journal of Food Microbiology. 206:109-117.
- Lacombe, A.C., Niemira, B.A., Gurtler, J., Fan, X., Sites, J.E., Boyd, G., Chen, H. 2015. Atmospheric cold plasma inactivation of Aerobic Microorganisms on blueberries and effects on quality attributes. Food Microbiology. 46:479-484.
- Ukuku, D.O., Huang, L., Sommers, C.H. 2014. Survival and growth parameters of Escherichia coli 0157:H7, Salmonella Spp. and Listeria monocytogenes on cantaloupe fresh-cut pieces during storage. Journal of Food Protection. 78:1288-1295.
- Ukuku, D.O., Geveke, D.J., Mukhopadhyay, S., Olanya, O.M., Juneja, V.K. 2014. Survival, injury and inactivation of Escherichia coli 0157:H7, salmonella and aerobic mesophilic bacteria in apple juice and cider amended with nisin-edta. Journal of Food Processing and Technology. 5:385.
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Progress 10/01/13 to 09/30/14
Outputs
Progress Report Objectives (from AD-416): The overall goal of this research is to reduce the risk of foodborne illness associated with the consumption of produce and shell eggs. Effective postharvest intervention technologies for these foods have proven difficult to implement and, therefore, are on the FDA Center for Food Safety and Applied Nutrition's list of highest research priorities. This new project was formed to apply proven engineering expertise to the development of efficient intervention strategies for challenging foods such as shell eggs, fresh produce and frozen produce. While other projects continue looking at intervention methods such as hot water immersion, irradiation and cold plasma for these types of foods, the proposed project will research novel technologies including microwave, radio frequency, UV, and flash steam. The specific objectives of the research program are as follows: 1: Develop, evaluate, and validate through laboratory and pilot-plant processing the effect of single and combinations of intervention technologies on pathogen reduction in eggs. Specifically, conduct research to "pasteurize" shell eggs using technologies, such as microwave heating or ozone-based combination treatments. 2: Develop, evaluate, and validate through laboratory and pilot-plant processing the effect of single and combinations of intervention technologies on pathogen reduction in fresh produce. For example, engineer flash steam and UV treatments and develop antimicrobial/ antioxidant compounds of GRAS origin as a processing aid for fruits and vegetables. 2A: Develop and evaluate a hurdle approach to inactivate Salmonella spp. and E. coli O157:H7 from tomato stem scar tissue. Application of thermal energy to the stem scar region of the tomato will be employed for the destruction of pathogens and to expose bacteria to subsequent treatments including antimicrobial immersion. 2B: Develop and evaluate a novel approach to inactivate Salmonella and E. coli O157:H7 on berries by an antimicrobial water agitation treatment. Aerated turbulence and vacuum will be applied to berries in order to remove particulate matter and expose niches within the host tissue to antimicrobials. 2C: Develop and evaluate a hurdle approach to inactivate Salmonella spp., L. monocytogenes and E. coli O157:H7 on fresh fruits and vegetables using individual treatments or a combination of antimicrobials and flash steam. 3: Develop, evaluate, and validate through laboratory and pilot-plant processing the effect of single and combinations of intervention technologies on pathogen reduction for frozen fruits and vegetables. Currently some vegetables are processed through snap freezing. It might be possible to develop a steam pasteurization processing technology that would allow vegetables to be stored refrigerated instead of frozen while having a stable shelf life. Approach (from AD-416): Radio frequency (RF) heating intervention technology will be developed that requires less time to pasteurize shell eggs than hot water immersion. A 4 kW RF unit will be modified to enable the application of RF energy to a shell egg. Another option to improve heating uniformity is to immerse the shell eggs in a liquid while applying RF energy. In addition, nonthermal ozone treatment of shell eggs will be evaluated for reducing Salmonella. Combinations of these technologies, such as ozone and RF, will be investigated. Shell eggs will be sent to Dr. Deana Jones (Athens, GA) for extensive quality tests including foaming ability, Haugh unit, yolk index, as well as turbidity and viscosity of the egg white. Tomatoes will be inoculated and the current practice of trimming stem-scar tissue will be tested to determine if subsequent cross-contamination of tomatoes occurs during traditional stem-scar removal. Vacuum perfusion sanitization will be used in combination with chemical sanitizers for the decontamination of Salmonella and E. coli from tomatoes. A novel localized heat treatment for the physical inactivation of Salmonella within the stem scar of tomatoes will be developed. Our engineers will modify existing technology currently used for the electrical thermal dehorning of sheep, goats and cattle. Berries will be inoculated and a hurdle approach to decontaminating berries will be applied by the use of sanitizers in combination with physical treatments such as applied vacuum perfusion, or aerated turbulence of water. Fruit (including melon, apple, tomato, pepper, mango, cucumber, and pear) surfaces will be inoculated and a novel antimicrobial treatment will be developed that will not impact the sensorial quality. The kinetics and mechanism of inactivation of the developed antimicrobial wash solutions will be investigated. Flash steam technology will be used to inactivate bacteria on such fruits and vegetables as peppers, cantaloupes, mangoes, green onions, parsley, cabbage, cucumbers, and radishes. The produce will be evaluated for thermal and mechanical damage using a texture analyzer and colorimeter. Frozen fruit (e.g., berries) and vegetables (e.g., corn and peas) will be inoculated and GRAS antimicrobial compounds will be used to sensitize foodborne pathogens to UV light inactivation and inhibit growth of pathogens on thawed fruits and vegetables. The bacterial inactivation using pulsed UV bulbs, that provide higher intensities than 254 nm UV bulbs, will be investigated. The latest technology to emerge is UV-LED (light-emitting diode). UV-LEDs are compact, do not fail as quickly as other types of UV bulbs, and have a potential for significant energy savings. The shell egg pasteurization process, developed by ARS scientists at Wyndmoor, Pennsylvania last year using Escherichia coli, was shown to be capable of inactivating 99.999% of Salmonella. This is important because the bacteria of concern related to the consumption of uncooked or undercooked eggs are Salmonella. The process uses radio frequency (RF) to pasteurize shell eggs within 20 min and maintains the transparency of the egg white. The collaboration continues with ARS scientists at Athens, Georgia to evaluate the egg quality. Preliminary results indicate that the functionality of the RF processed eggs was superior compared to that of eggs pasteurized using the conventional 60 min hot water immersion process. A funded CRADA was signed with an industrial partner with the objective of scaling up and commercializing the RF shell egg pasteurization process. The role of pyrolysis biochar in accelerating the inactivation of pathogens in crop soil, in order to inhibit the contamination of fresh produce, was studied. Biochar application accelerated the inactivation of E. coli O157:H7 and Salmonella, inactivating more than 99.9999% in 5 weeks. Work also continued on a 5- year NIFA-funded project in conjunction with the University of Delaware. A post-doctoral research assistant was hired on this project and has been investigating a potential surrogate virus for human norovirus. Tulane monkey virus is being evaluated for its resistance to various sanitizing compounds, to reduce the risk of foodborne illness on fresh produce. Work from an additional industry-funded CRADA involves testing sundry novel industry antimicrobials for inactivating Salmonella, E. coli O157:H7 and Listeria monocytogenes in vitro, as well as following their inoculation onto fresh produce. The interactive effects of temperature, pH, and water activity on the growth kinetics of Shiga toxin�producing E. coli O104:H43 was studied and used to develop second-order predictive models to estimate the growth potential in foods. These models will provide risk assessors and food safety managers a rapid means of estimating the likelihood that the pathogen, if present, would grow. The behavior of native microbial populations of WPC-34 and WPC-80 whey protein stored at different temperatures was investigated using a conventional and a rapid bioluminescent Adenosine Triphosphate (ATP) assay that does not require up to 3 days incubation before results are achieved. Total microbial populations in the whey proteins determined immediately and after 7 days storage did not show significant changes. The results indicate that bioluminescent ATP assay can be used to estimate total microbial populations in the samples. The effects of ultraviolet-C (UV-C) light treatment on inactivation of Salmonella Enterica and E. coli O157:H7 on grape tomato surface and stem scars and quality was investigated. The treatment was effective in controlling native microbial loads during storage at 4 C. The treatment did not affect the firmness of tomato and its color during storage suggesting that UV-C radiation could potentially be used for sanitizing fresh tomatoes and extending shelf-life. Accomplishments 01 Shell eggs pasteurization technology transferred to industry. The shell egg pasteurization technology, recently developed by ARS researchers at Wyndmoor, Pennsylvania, needs to be scaled up in order to supply consumers with safer and higher-quality eggs. Numerous companies expressed substantial interest in the radio frequency shell egg technology during the past year. The lab-scale prototype was demonstrated to several companies. After a thorough review, a funded CRADA was signed with one of the companies to scale up and commercialize the pasteurization process. Pasteurization of all shell eggs in the U.S. would reduce annual Salmonella illnesses by approximately 110,000. 02 Antimicrobial wash solution for fresh and fresh cut produce. The goal of this work was to collaborate with an industry partner through an established CRADA to develop an antimicrobial wash solution to inactivate pathogens on fresh produce. ARS researchers at Wyndmoor, Pennsylvania, tested numerous combinations of GRAS (generally recognized as safe) compounds for inactivating foodborne bacterial pathogens. The selected antimicrobial solution inactivated bacteria in rinse water under clean conditions and dirty conditions as follows: A provisional patent has been filed for this solution, which will provide processors another option for reducing foodborne pathogens in fresh produce.
Impacts
(N/A)
Publications
- Yan, R., Mattheis, J.P., Gurtler, J., Sites, J.E., Fan, X. 2014. UV-C inactivation of Escherichia coli and dose uniformity on apricot fruit in a commercial setting. Postharvest Biology and Technology. doi.org/10.1016/j. postharvbio.2014.04.005.
- Juneja, V.K., Mukhopadhyay, S., Ukuku, D.O., Hwang, C., Wu, V.C., Harshavardhan, T. 2014. Interactive effects of temperature, pH, and water activity on the growth kinetics of Shiga-toxin producing Escherichia coli O104:H4. Journal of Food Protection. 77(5):706-712 doi:10.431/0362- 028XJFP-13-387.
- Mukhopadhyay, S., Ukuku, D.O., Juneja, V.K., Fan, X. 2014. Effects of UV-C treatment on inactivation of Salmonella and Escherichia coli O157:H7 on tomato surface and steam scars, native microbial loads, and quality of grape tomatoes. Food Control.
- Yan, X., Gurtler, J. 2014. Cronobacter (Enterobacter) sakazakii. Encyclopedia of Food Microbiology. vol 1. In: Batt, C.A., Tortorello, M.L. (Eds.), Elsevier Ltd, Academic Press. pp. 528-532.
- Yun, J., Yan, R., Fan, X., Gurtler, J., Phillips, J.G. 2013. Fate of E. coli O157:H7, Salmonella spp. and potential surrogate bacteria on apricot fruit following UV-C light. International Journal of Food Microbiology. 166:356-363.
- Guo, M., Jin, Z.T., Geveke, D.J., Fan, X., Sites, J.E., Wang, L. 0203. Evaluation of microbial stability, bioactive compounds, physicochemical properties, and consumer acceptance of pomegranate juice processed in a commercial scale pulsed electric field system. Food and Bioprocess Technology. DOI:10.1007/s11947-013-1185-6.
- Ukuku, D.O., Onwulata, C.I., Thomas-Gahring, A.E., Mukhopadhyay, S., Tunick, M.H. 2014. Behavior of native microbial populations of WPC-34 and WPC-80 whey protein stored at different temperatures. Journal of Food Processing and Technology.
- Sampredo, F., Mcaloon, A.J., Yee, W.C., Fan, X., Geveke, D.J. 2014. Cost analysis and environmental impact of nonthermal technologies. Food and Bioprocess Technology. DOI:10.1007/s11947-014-1298-6.
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Progress 10/01/12 to 09/30/13
Outputs
Progress Report Objectives (from AD-416): The overall goal of this research is to reduce the risk of foodborne illness associated with the consumption of produce and shell eggs. Effective postharvest intervention technologies for these foods have proven difficult to implement and, therefore, are on the FDA Center for Food Safety and Applied Nutrition's list of highest research priorities. This new project was formed to apply proven engineering expertise to the development of efficient intervention strategies for challenging foods such as shell eggs, fresh produce and frozen produce. While other projects continue looking at intervention methods such as hot water immersion, irradiation and cold plasma for these types of foods, the proposed project will research novel technologies including microwave, radio frequency, UV, and flash steam. The specific objectives of the research program are as follows: 1: Develop, evaluate, and validate through laboratory and pilot-plant processing the effect of single and combinations of intervention technologies on pathogen reduction in eggs. Specifically, conduct research to "pasteurize" shell eggs using technologies, such as microwave heating or ozone-based combination treatments. 2: Develop, evaluate, and validate through laboratory and pilot-plant processing the effect of single and combinations of intervention technologies on pathogen reduction in fresh produce. For example, engineer flash steam and UV treatments and develop antimicrobial/ antioxidant compounds of GRAS origin as a processing aid for fruits and vegetables. 2A: Develop and evaluate a hurdle approach to inactivate Salmonella spp. and E. coli O157:H7 from tomato stem scar tissue. Application of thermal energy to the stem scar region of the tomato will be employed for the destruction of pathogens and to expose bacteria to subsequent treatments including antimicrobial immersion. 2B: Develop and evaluate a novel approach to inactivate Salmonella and E. coli O157:H7 on berries by an antimicrobial water agitation treatment. Aerated turbulence and vacuum will be applied to berries in order to remove particulate matter and expose niches within the host tissue to antimicrobials. 2C: Develop and evaluate a hurdle approach to inactivate Salmonella spp., L. monocytogenes and E. coli O157:H7 on fresh fruits and vegetables using individual treatments or a combination of antimicrobials and flash steam. 3: Develop, evaluate, and validate through laboratory and pilot-plant processing the effect of single and combinations of intervention technologies on pathogen reduction for frozen fruits and vegetables. Currently some vegetables are processed through snap freezing. It might be possible to develop a steam pasteurization processing technology that would allow vegetables to be stored refrigerated instead of frozen while having a stable shelf life. Approach (from AD-416): Radio frequency (RF) heating intervention technology will be developed that requires less time to pasteurize shell eggs than hot water immersion. A 4 kW RF unit will be modified to enable the application of RF energy to a shell egg. Another option to improve heating uniformity is to immerse the shell eggs in a liquid while applying RF energy. In addition, nonthermal ozone treatment of shell eggs will be evaluated for reducing Salmonella. Combinations of these technologies, such as ozone and RF, will be investigated. Shell eggs will be sent to Dr. Deana Jones (Athens, GA) for extensive quality tests including foaming ability, Haugh unit, yolk index, as well as turbidity and viscosity of the egg white. Tomatoes will be inoculated and the current practice of trimming stem-scar tissue will be tested to determine if subsequent cross-contamination of tomatoes occurs during traditional stem-scar removal. Vacuum perfusion sanitization will be used in combination with chemical sanitizers for the decontamination of Salmonella and E. coli from tomatoes. A novel localized heat treatment for the physical inactivation of Salmonella within the stem scar of tomatoes will be developed. Our engineers will modify existing technology currently used for the electrical thermal dehorning of sheep, goats and cattle. Berries will be inoculated and a hurdle approach to decontaminating berries will be applied by the use of sanitizers in combination with physical treatments such as applied vacuum perfusion, or aerated turbulence of water. Fruit (including melon, apple, tomato, pepper, mango, cucumber, and pear) surfaces will be inoculated and a novel antimicrobial treatment will be developed that will not impact the sensorial quality. The kinetics and mechanism of inactivation of the developed antimicrobial wash solutions will be investigated. Flash steam technology will be used to inactivate bacteria on such fruits and vegetables as peppers, cantaloupes, mangoes, green onions, parsley, cabbage, cucumbers, and radishes. The produce will be evaluated for thermal and mechanical damage using a texture analyzer and colorimeter. Frozen fruit (e.g., berries) and vegetables (e.g., corn and peas) will be inoculated and GRAS antimicrobial compounds will be used to sensitize foodborne pathogens to UV light inactivation and inhibit growth of pathogens on thawed fruits and vegetables. The bacterial inactivation using pulsed UV bulbs, that provide higher intensities than 254 nm UV bulbs, will be investigated. The latest technology to emerge is UV-LED (light-emitting diode). UV-LEDs are compact, do not fail as quickly as other types of UV bulbs, and have a potential for significant energy savings. A radio frequency (RF) energy process was developed that has great potential to substantially increase the number of eggs pasteurized in the US, thus significantly reducing illness from Salmonella bacteria. The collaboration continues with ARS scientists at Athens Georgia to evaluate the egg quality. Also, shell eggs were treated with ozone, an oxidizing antimicrobial agent. The reduction of Salmonella using the ozone was insignificant, probably due to the difficulty of the ozone to penetrate the shell. Studies were performed on the efficacy of sanitizers against Salmonella and E. coli O157:H7 on strawberries as well as on tomato stem scars. Sanitizers inactivated over 99.999% and 99.9% of these pathogens on tomato stem scars and strawberries, respectively. Results indicated that vacuum perfusion did not increase the inactivation of bacteria on fruits washed with antimicrobial solutions. A paper was published in the International Journal of Food Microbiology detailing the research. Work continued on a 36-month CRADA entitled, �Development of Produce Wash for Microbial Decontamination of Fresh Fruits and Vegetables�. Work also continued on a 5-year NIFA-funded project in conjunction with the University of Delaware, entitled, �Inactivation of Enteric Foodborne Viruses in High Risk Foods by Non-Thermal Processing Technologies�. An Auburn University postdoctoral research associate began work on a 2-year NIFA-funded Fellows project investigating the role of fast-pyrolysis biochar in accelerating the inactivation of E. coli O157:H7 and Salmonella in crop soil over time, in order to inhibit the contamination of fresh produce. Another scientist is researching the behavior of Salmonella spp. on inoculated fresh-cut cantaloupe pieces processed with organic acids stored at different temperatures and the overall acceptability of the treated cantaloupe cubes. Sodium lactate treatment resulted in the highest acceptability score, 8 (with 10 being the highest rating), and it provided an additional viability loss of 30 percent for Salmonella spp. Finally, membrane damage and viability loss of E. coli O157:H7 and Salmonella spp. in apple juice treated with heat and with nonthermal high hydrostatic pressure and were investigated to understand the relationship of heat and pressure on mechanism of inactivation. A 350 MPa pressure at 35 C led to the collapse of the bacterial membrane. The damaged bacteria did not recover during refrigerated storage. Manuscripts on these last two studies have been accepted for publication in scientific journals. Using an experimental UV light emitting diode (UV- LED) system, that was designed and assembled in-house, E. coli was reduced by 99.999% and 99.7% in a liquid solution and on the surface of a tomato, respectively. This is the first study to show that bacteria on foods can be inactivated using nonthermal UV LED technology. The next step is to study the energy costs of the UV-LED process. Significant Activities that Support Special Target Populations: A Co-Pi on Grant proposal with Dr. Lamin Kassama, Alabama A & M. Univ. A Historically Black University. Accomplishments 01 Shell eggs pasteurized using innovative RF process look great. Pasteurization of all shell eggs in the U.S. would reduce Salmonella illnesses by approximately 110,000 annually, yet only about 1 percent of eggs are currently pasteurized because the process is costly and damages the egg white appearance. ARS researchers, at Wyndmoor, Pennsylvania, developed a radio frequency (RF) energy process that eliminates 99.999 percent of Salmonella, that may be present in eggs. The RF process is significantly faster than the current pasteurization process, by more than 50 percent, and the egg whites look perfect. The ARS has filed for patent protection and several companies have expressed interest in licensing the technology. RF pasteurization substantially reduces the threat of illness from uncooked and undercooked shell eggs, allowing consumers to enjoy their favorite recipes and styles.
Impacts
(N/A)
Publications
- Ukuku, D.O., Mukhopadhyay, S., Onwulata, C.I. 2013. Effect of storage temperature on survival and recovery of thermal and extrusion injured Escherichia coli populations in whey protein concentrate and corn meal. Foodborne Pathogens and Disease. Volume 10(1):62-68.
- Geveke, D.J., Torres, D. 2012. Liquid egg white pasteurization using a centrifugal UV irradiator. International Journal of Food Microbiology. 162(2013):43-47.
- Ukuku, D.O., Olanya, O.M., Geveke, D.J., Sommers, C.H. 2012. Transfer of Listeria monocytogenes serovars from cantaloupe rind surfaces to fresh cut pieces during preparation: effect of native microflora waiting period and storage temperature on the population of pathogens. Journal of Food Protection. 75(11)1912-1919.
- Sampedro, F., Mcaloon, A.J., Yee, W.C., Fan, X., Zhang, H.Q., Geveke, D.J. 2013. Cost analysis of commercial pasteurization of orange juice by pulsed electric fields. Innovative Food Science and Emerging Technologies. 17:72- 78.
- Gurtler, J., Douds, D.D., Dirks, B.A., Quinlan, J.J., Nicholson, A., Phillips, J.G., Niemira, B.A. 2013. Survival of Salmonella and E.coli O157:H7 in soil and translocation into leek (allium porrum) as influenced by mycorrhizal fungi. Applied and Environmental Microbiology. 79:1813-1820.
- Yu, M., Huang, Y., Gurtler, J., Niemira, B.A., Sites, J.E., Chen, H. 2013. Effects of storage conditions before or after high-hydrostatic pressure on inactivation of Vibrio parahaemolyticus and Vibrio vulnificus in oysters. International Journal of Food Microbiology. 163(2013):146-152.
- Jin, Z.T., Gurtler, J., Li, S. 2013. Development of antimicrobial coatings for improving the microbiological safety and quality of shell eggs. Journal of Food Protection. 76(5)779-785.
- Gurtler, J., Smelser, A., Niemira, B.A., Jin, Z.T., Yan, X., Geveke, D.J. 2012. Inactivation of Salmonella enterica on tomato stem scars by sanitizing solutions and vacuum perfusion. International Journal of Food Microbiology. 159:84-92.
- Yan, X., Gurtler, J., Fratamico, P.M., Hu, J., Juneja, V.K. 2012. Phylogenetic identification of bacterial MazF toxin protein motifs among probiotic strains and foodborne pathogens and potential implications of engineered probiotic intervention in food. BioMed Central(BMC) Cell & Bioscience. 2:39.
- Yuk, H., Sampedro, F., Fan, X., Geveke, D.J. 2012. Nonthermal processing of orange juice using a pilot-plant scale supercritical carbon dioxide system with a gas-liquid metal contactor. Journal of Food Processing and Preservation. DOI:10.1111/jfpp.12013.
- Ukuku, D.O., Yamamoto, K., Bari, M., Mukhopadhyay, S., Juneja, V.K., Kawamoto, S. 2013. Membrane damage and viability loss of thermally treated and high hydrostatic pressurized E. coli 0157:H7 and Salmonella spp. in apple juice. Journal of Food Processing and Technology. 4:236 doi:10.4172/ 2157-7110.1000236.
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Progress 10/01/11 to 09/30/12
Outputs
Progress Report Objectives (from AD-416): The overall goal of this research is to reduce the risk of foodborne illness associated with the consumption of produce and shell eggs. Effective postharvest intervention technologies for these foods have proven difficult to implement and, therefore, are on the FDA Center for Food Safety and Applied Nutrition's list of highest research priorities. This new project was formed to apply proven engineering expertise to the development of efficient intervention strategies for challenging foods such as shell eggs, fresh produce and frozen produce. While other projects continue looking at intervention methods such as hot water immersion, irradiation and cold plasma for these types of foods, the proposed project will research novel technologies including microwave, radio frequency, UV, and flash steam. The specific objectives of the research program are as follows: 1: Develop, evaluate, and validate through laboratory and pilot-plant processing the effect of single and combinations of intervention technologies on pathogen reduction in eggs. Specifically, conduct research to "pasteurize" shell eggs using technologies, such as microwave heating or ozone-based combination treatments. 2: Develop, evaluate, and validate through laboratory and pilot-plant processing the effect of single and combinations of intervention technologies on pathogen reduction in fresh produce. For example, engineer flash steam and UV treatments and develop antimicrobial/antioxidant compounds of GRAS origin as a processing aid for fruits and vegetables. 2A: Develop and evaluate a hurdle approach to inactivate Salmonella spp. and E. coli O157:H7 from tomato stem scar tissue. Application of thermal energy to the stem scar region of the tomato will be employed for the destruction of pathogens and to expose bacteria to subsequent treatments including antimicrobial immersion. 2B: Develop and evaluate a novel approach to inactivate Salmonella and E. coli O157:H7 on berries by an antimicrobial water agitation treatment. Aerated turbulence and vacuum will be applied to berries in order to remove particulate matter and expose niches within the host tissue to antimicrobials. 2C: Develop and evaluate a hurdle approach to inactivate Salmonella spp., L. monocytogenes and E. coli O157:H7 on fresh fruits and vegetables using individual treatments or a combination of antimicrobials and flash steam. 3: Develop, evaluate, and validate through laboratory and pilot-plant processing the effect of single and combinations of intervention technologies on pathogen reduction for frozen fruits and vegetables. Currently some vegetables are processed through snap freezing. It might be possible to develop a steam pasteurization processing technology that would allow vegetables to be stored refrigerated instead of frozen while having a stable shelf life. Approach (from AD-416): Radio frequency (RF) heating intervention technology will be developed that requires less time to pasteurize shell eggs than hot water immersion. A 4 kW RF unit will be modified to enable the application of RF energy to a shell egg. Another option to improve heating uniformity is to immerse the shell eggs in a liquid while applying RF energy. In addition, nonthermal ozone treatment of shell eggs will be evaluated for reducing Salmonella. Combinations of these technologies, such as ozone and RF, will be investigated. Shell eggs will be sent to Dr. Deana Jones (Athens, GA) for extensive quality tests including foaming ability, Haugh unit, yolk index, as well as turbidity and viscosity of the egg white. Tomatoes will be inoculated and the current practice of trimming stem-scar tissue will be tested to determine if subsequent cross-contamination of tomatoes occurs during traditional stem-scar removal. Vacuum perfusion sanitization will be used in combination with chemical sanitizers for the decontamination of Salmonella and E. coli from tomatoes. A novel localized heat treatment for the physical inactivation of Salmonella within the stem scar of tomatoes will be developed. Our engineers will modify existing technology currently used for the electrical thermal dehorning of sheep, goats and cattle. Berries will be inoculated and a hurdle approach to decontaminating berries will be applied by the use of sanitizers in combination with physical treatments such as applied vacuum perfusion, or aerated turbulence of water. Fruit (including melon, apple, tomato, pepper, mango, cucumber, and pear) surfaces will be inoculated and a novel antimicrobial treatment will be developed that will not impact the sensorial quality. The kinetics and mechanism of inactivation of the developed antimicrobial wash solutions will be investigated. Flash steam technology will be used to inactivate bacteria on such fruits and vegetables as peppers, cantaloupes, mangoes, green onions, parsley, cabbage, cucumbers, and radishes. The produce will be evaluated for thermal and mechanical damage using a texture analyzer and colorimeter. Frozen fruit (e.g., berries) and vegetables (e.g., corn and peas) will be inoculated and GRAS antimicrobial compounds will be used to sensitize foodborne pathogens to UV light inactivation and inhibit growth of pathogens on thawed fruits and vegetables. The bacterial inactivation using pulsed UV bulbs, that provide higher intensities than 254 nm UV bulbs, will be investigated. The latest technology to emerge is UV-LED (light-emitting diode). UV-LEDs are compact, do not fail as quickly as other types of UV bulbs, and have a potential for significant energy savings. For objective 1, pasteurization of shell eggs, experiments on evaluating the hot water immersion method have been completed. Salmonella was reduced by 4.5 log (99.997%) following treatment at 56.7 deg C for 60 min. The quality of the hot water pasteurized eggs was evaluated. In addition, pasteurized eggs were refrigerated for 4 weeks to determine the fate of the surviving Salmonella. Regarding objective 2, pathogen reduction in fresh produce, a scientist investigated the cross-contamination of Salmonella-inoculated tomato stem scars after removing them with a knife and then slicing the same tomato with the same knife. Approximately 30% of tomatoes became contaminated; however, stem scars that were entirely removed (without the knife blade touching the inoculated stem scar) did not further contaminate the tomato. Experiments were performed on inactivating Salmonella and E. coli O157:H7 on strawberries by means of more than 50 different sanitizing wash combinations. In addition, a scientist became the ADODR on a 36 month CRADA entitled, �Development of produce wash for microbial decontamination of fresh fruits and vegetables. � The industry partner will provide $65,000 to ARS. Work continued on optimizing high pressure processing of foods for inactivating pathogenic bacteria and viruses. One manuscript was published in Applied and Environmental Microbiology. A scientist completed studies investigating the internalization of Salmonella and E. coli O157:H7 into both leek and baby Romaine lettuce as affected by mycorrhizal fungi in the soil. Results showed that fungi may increase the survivability of Salmonella and E. coli O157:H7 in leek plants but not in baby Romaine lettuce. A novel antimicrobial wash solution containing certain short chain organic acids generally regarded as safe is being developed. The ability of microbial inactivation by individual organic acids was tested to optimize effective concentrations. Treatment of melons, cucumber and tomatoes with the novel antimicrobial solution at ambient temperature and 60 deg C for 3 minutes resulted in a population reduction of 4.5 and 6 log (99.997 and 99.9999%), respectively. In addition, research was undertaken to investigate bacterial surface charge and strength of attachment for non- pathogenic surrogates (E. coli ATCC 25922 and ATCC 35218) and human bacterial pathogens (Salmonella serovars, E. coli O157:H7 and Listeria monocytogenes) on cantaloupe surfaces. The information will provide the food processing industry and research institutions the necessary parameters of specific bacterial surrogates for pilot plant studies. For objective 3, pathogen reduction for frozen fruits and vegetables, a nonthermal UV-LED experimental system was designed and assembled. Preliminary experiments indicated that E. coli is inactivated by the UV- LED system. Accomplishments 01 Listeria monocytogenes is transferred from cantaloupe rind surfaces to fresh cut pieces during preparation. Recent outbreaks of foodborne listeriosis due to consumption of contaminated cantaloupes led ARS researchers at Wyndmoor, Pennsylvania to investigate the effects of holding time prior to refrigeration as well as variations in storage temperatures on survival of L. monocytogenes transferred to fresh-cut pieces during preparation. Holding contaminated fresh-cut melon pieces a 20 deg C for 4 h or more prior to refrigeration (5 deg C) increased the chances of L. monocytogenes proliferation. The information will help foo service industry and consumers as well as fresh-cut processors in implementing HACCP plans and good manufacturing practices (GMP�s). 02 Salmonella contamination occurs in the stem scars of tomatoes. The goal of this work was to determine antimicrobial treatments effective at inactivating Salmonella on tomato stem scars with or without vacuum perfusion. ARS researchers at Wyndmoor, Pennsylvania tested sixty-three antimicrobial combinations against Salmonella on tomato stem scars. Twenty-four of the antimicrobial washes inactivated more than 3.0 log CFU/g (99.9%). Even more Salmonella, 4.8 log (99.998%), were reduced by seven of the washes (viz., 40% ethanol, sulfuric acid, in addition to fi organic acid combinations). Vacuum perfusion + 200 ppm chlorine increas inactivation by 0.7 log (80%) over chlorine alone. Results from this stu provide tomato processers with sanitization options effective at inactivating Salmonella from the stem scars of tomatoes. 03 Existing method for pasteurizing shell eggs significantly affects qualit Currently, hot water immersion is the only commercial method used to pasteurize eggs and it may damage egg functional properties. In the initial phase of this research, shell eggs were inoculated with Salmonel and immersed in hot water at various temperatures for various times. ARS researchers at Wyndmoor, Pennsylvania determined that Salmonella was reduced by 4.5 log (99.997%) following treatment at 56.7 deg C for 60 mi The hot water pasteurized eggs were then refrigerated for 4 weeks to determine the fate of the surviving Salmonella. The Salmonella neither grew nor died during the storage. In the final phase of the research, th quality of the eggs was evaluated in collaboration with ARS scientists a Athens, Georgia. Compared to fresh (unpasteurized) eggs, the hot water immersion eggs had significantly greater shell dynamic stiffness, albume height, and Haugh unit score and significantly lower yolk index. There w no significant difference in shell strength or vitelline membrane elasticity. This research established that current pasteurization method affect egg quality parameters and that an alternate pasteurization metho is required.
Impacts
(N/A)
Publications
- Bari, M., Hossain, M., Isshiki, K., Ukuku, D.O. 2011. Behavior of Yersinian enteriocolitica in foods. Journal of Pathogens. 420732:1-13.
- Geveke, D.J., Torres, D. 2012. Pasteurization of grapefruit juice using a centrifugal ultraviolet light irradiator. Journal of Food Engineering. 111(2):241-246.
- Chen, W., Jin, Z.T., Gurtler, J., Geveke, D.J., Fan, X. 2012. Inactivation of Salmonella on whole cantaloupe by application of an antimicrobial coating containing chitosan and allyl isothiocyanate. International Journal of Food Microbiology. 155:165-170.
- Geveke, D.J., Boyd, G., Zhang, H.Q. 2011. UV penetration depth in liquid egg white and liquid whole egg. Journal of Food Processing and Preservation. 35:754-757.
- Ukuku, D.O., Onwulata, C.I., Mukhopadhyay, S. 2012. Behavior of Escherichia coli bacteria in whey protein and corn meal during twin screw extrusion processing at different temperatures. Journal of Food Processing and Technology. 3(4):1000150.
- Jin, Z.T., Gurtler, J. 2012. Inactivation of Salmonella on tomato stem scars by edible chitosan and organic acid coatings. Journal of Food Protection. 75(8):1368-1372.
- Yan, X., Gurtler, J., Fratamico, P.M., Hu, J., Gunther, N.W., Juneja, V.K., Huang, L. 2011. Comprehensive approaches for molecular biomarker discovery for the detection and identification of Cronobacter spp. (Enterobacter sakazakii), Salmonella, and other foodborne pathogens. Applied and Environmental Microbiology. 77:1833-1843.
- Ukuku, D.O., Geveke, D.J., Cooke, P.H. 2012. Effect of thermal and radio frequency electric fields treatments on Escherichia coli bacteria in apple juice. Journal of Microbial and Biochemical Technology. 4(3):076-081.
- Gurtler, J., Jin, Z.T. 2012. Propyl paraben sensitizes heat-resistant Salmonella Enteritidis and Oranienburg to thermal inactivation in liquid egg albumen. Journal of Food Protection. 75(3):443-448.
- Ukuku, D.O., Md. Latiful, B., Kawamoto, S. 2012. Hydrogen peroxide. In: Gomez-Lopez, V.M., editor. Decontamination of Fresh and Minimally Processed Produce. First Edition. Ames, IA: John Wiley & Sons, Inc. p. 197- 214.
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Progress 10/01/10 to 09/30/11
Outputs
Progress Report Objectives (from AD-416) The overall goal of this research is to reduce the risk of foodborne illness associated with the consumption of produce and shell eggs. Effective postharvest intervention technologies for these foods have proven difficult to implement and, therefore, are on the FDA Center for Food Safety and Applied Nutrition�s list of highest research priorities. This new project was formed to apply proven engineering expertise to the development of efficient intervention strategies for challenging foods such as shell eggs, fresh produce and frozen produce. While other projects continue looking at intervention methods such as hot water immersion, irradiation and cold plasma for these types of foods, the proposed project will research novel technologies including microwave, radio frequency, UV, and flash steam. The specific objectives of the research program are as follows: 1: Develop, evaluate, and validate through laboratory and pilot-plant processing the effect of single and combinations of intervention technologies on pathogen reduction in eggs. Specifically, conduct research to �pasteurize� shell eggs using technologies, such as microwave heating or ozone-based combination treatments. 2: Develop, evaluate, and validate through laboratory and pilot-plant processing the effect of single and combinations of intervention technologies on pathogen reduction in fresh produce. For example, engineer flash steam and UV treatments and develop antimicrobial/ antioxidant compounds of GRAS origin as a processing aid for fruits and vegetables. 2A: Develop and evaluate a hurdle approach to inactivate Salmonella spp. and E. coli O157:H7 from tomato stem scar tissue. Application of thermal energy to the stem scar region of the tomato will be employed for the destruction of pathogens and to expose bacteria to subsequent treatments including antimicrobial immersion. 2B: Develop and evaluate a novel approach to inactivate Salmonella and E. coli O157:H7 on berries by an antimicrobial water agitation treatment. Aerated turbulence and vacuum will be applied to berries in order to remove particulate matter and expose niches within the host tissue to antimicrobials. 2C: Develop and evaluate a hurdle approach to inactivate Salmonella spp., L. monocytogenes and E. coli O157:H7 on fresh fruits and vegetables using individual treatments or a combination of antimicrobials and flash steam. 3: Develop, evaluate, and validate through laboratory and pilot-plant processing the effect of single and combinations of intervention technologies on pathogen reduction for frozen fruits and vegetables. Currently some vegetables are processed through snap freezing. It might be possible to develop a steam pasteurization processing technology that would allow vegetables to be stored refrigerated instead of frozen while having a stable shelf life. Approach (from AD-416) Radio frequency (RF) heating intervention technology will be developed that requires less time to pasteurize shell eggs than hot water immersion. A 4 kW RF unit will be modified to enable the application of RF energy to a shell egg. Another option to improve heating uniformity is to immerse the shell eggs in a liquid while applying RF energy. In addition, nonthermal ozone treatment of shell eggs will be evaluated for reducing Salmonella. Combinations of these technologies, such as ozone and RF, will be investigated. Shell eggs will be sent to collaborators, (USDA/ARS in Athens, GA) for extensive quality tests including foaming ability, Haugh unit, yolk index, as well as turbidity and viscosity of the egg white. Tomatoes will be inoculated and the current practice of trimming stem-scar tissue will be tested to determine if subsequent cross- contamination of tomatoes occurs during traditional stem-scar removal. Vacuum perfusion sanitization will be used in combination with chemical sanitizers for the decontamination of Salmonella and E. coli from tomatoes. A novel localized heat treatment for the physical inactivation of Salmonella within the stem scar of tomatoes will be developed. Our engineers will modify existing technology currently used for the electrical thermal dehorning of sheep, goats and cattle. Berries will be inoculated and a hurdle approach to decontaminating berries will be applied by the use of sanitizers in combination with physical treatments such as applied vacuum perfusion, or aerated turbulence of water. Fruit (including melon, apple, tomato, pepper, mango, cucumber, and pear) surfaces will be inoculated and a novel antimicrobial treatment will be developed that will not impact the sensorial quality. The kinetics and mechanism of inactivation of the developed antimicrobial wash solutions will be investigated. Flash steam technology will be used to inactivate bacteria on such fruits and vegetables as peppers, cantaloupes, mangoes, green onions, parsley, cabbage, cucumbers, and radishes. The produce will be evaluated for thermal and mechanical damage using a texture analyzer and colorimeter. Frozen fruit (e.g., berries) and vegetables (e.g., corn and peas) will be inoculated and GRAS antimicrobial compounds will be used to sensitize foodborne pathogens to UV light inactivation and inhibit growth of pathogens on thawed fruits and vegetables. The bacterial inactivation using pulsed UV bulbs, that provide higher intensities than 254 nm UV bulbs, will be investigated. The latest technology to emerge is UV-LED (light-emitting diode). UV-LEDs are compact, do not fail as quickly as other types of UV bulbs, and have a potential for significant energy savings. The project has just recently been certified by OSQR. The objectives, all of which fall under National Program 108, Component I.D., Intervention and Control Strategies, are significantly different from those of the last project. Progress was made on all three objectives. For objective 1, pasteurization of shell eggs, experiments have begun on evaluating the commercial method. Shell eggs were inoculated with salmonella and were immersed in hot water at various temperatures for various times. Salmonella was reduced by 4.5 log. The shelf life and quality of the eggs will be evaluated over the next six months. Regarding objective 2, pathogen reduction in fresh produce, vacuum perfusion sanitization was performed in conjunction with the use of chemical sanitizers for the decontamination of Salmonella from the stem scars of tomatoes. The vacuum perfusion method, in conjunction with sanitizers, did not significantly increase the level of Salmonella inactivation in the stem scars of tomatoes when compared with tomatoes that were not treated with vacuum perfusion treated tomatoes. Further studies with chemical sanitizers were sufficient to attain a = 5 log CFU/stem scar inactivation of Salmonella. Literature searches were conducted to determine the extent of cross contamination from trimming tomato stem scars as well as to assess the ability of antimicrobial immersions treatments to inactivate Salmonella and E. coli O157:H7 on berries. In addition, a project scientist recently became the ADODR on USDA-AFRI Grant, Award # 2011-68003-30005, for the project entitled �Inactivation of Enteric Foodborne Viruses in High Risk Foods by Non-Thermal Processing Technologies� which was subawarded $300,000 from the University of Delaware. The funds will be used to determine the effects of ultraviolet light, gamma irradiation, high pressure processing, antimicrobial sanitizers, and cold plasma treatment on human norovirus, hepatitis A virus, and rotavirus on strawberries, raspberries, blueberries, green onions, salsa, and other high risk foods. For objective 3, pathogen reduction for frozen fruits and vegetables, the design of a nonthermal UV- LED experimental system for improving the safety of frozen foods is ongoing.
Impacts
(N/A)
Publications
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