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United States Department of Agriculture

Agricultural Research Service


Location: Food Safety and Intervention Technologies

2007 Annual Report

1a.Objectives (from AD-416)
To reduce the risk of food borne illness associated with the consumption of meat and poultry, seafood and aquaculture, and complex ready-to-eat foods while maintaining product quality and extending shelf-life. The specific objectives of the research program are as follows: .
1)Utilize microbiological and molecular techniques to determine the effect of intervention technologies on microbial physiology, virulence and injury in order to assist in the design of effective process interventions;.
2)Develop and validate nonthermal and advanced thermal intervention technologies such as ionizing and UV radiation, radio-frequency and microwave heating, vacuum-steam-vacuum processing and ozonation to inactivate pathogens and spoilage microorganisms in raw and ready-to-eat meat and poultry, seafood and aquaculture products, and related complex solid foods, in combination with GRAS food additives;.
3)Define the impact of non-thermal and advanced thermal intervention technologies on food quality and chemistry.

1b.Approach (from AD-416)
D-values and the growth potential in shelf-life studies will be determined for foodborne pathogens using inoculated products following application of non-thermal and advanced thermal technologies. Particular attention will be focused on the use of multiple technologies, commonly known as the hurdle approach, to inactivate pathogens in foods. The effects of intrinsic and extrinsic factors such as processing variables, and product composition (temperature, dose, atmosphere, GRAS additives, pH, moisture, etc.) will be determined. Effects of interventions on the chemistry of foods and the formation and biological effect of toxicological markers will be determined using GC and GC-MS based technologies and bioassays.

Inactivation of Listeria monocytogenes in ready-to-eat meats: Ultraviolet light inactivation of Listeria monocytogenes on frankfurter surfaces: Frankfurters can occasionally become contaminated by the pathogen Listeria monocytogenes following cooking and prior to packaging, leading to product recalls and foodborne illness outbreaks. Ultraviolet light (UVC) was used to inactivate L. monocytogenes on the surfaces of frankfurters that contained the commonly used antimicrobials potassium lactate and sodium diacetate, in a laboratory setting. UVC inactivated 99 percent of Listeria on the frankfurters, and the antimicrobials prevented proliferation of the L. monocytogenes for 2 months under refrigerated storage conditions. The UVC process has the potential to reduce product recalls and foodborne illness outbreaks due to contamination by Listeria monocytogenes. NP 108 Food Safety 2006-2010 Action Plan Component(s) 1.2.4 Processing Intervention Strategies.

Time course of thermal inactivation kinetics of L. monocytogenes in beef: The foodborne pathogen Listeria monocytogenes is an occasional contaminant in raw and ready-to-eat meat products. Time course analysis is to understand the fundamental mechanism of bacterial inactivation at high temperature conditions, and kinetic models are used in the designing and evaluation of thermal processes. Traditionally it is believed that the bacterial inactivation follows the first order (or linear) kinetics. However, in the laboratory it is found that the inactivation of L. monocytogenes in beef does not always follows the first order kinetics. A new kinetic model was developed to describe the nonlinear inactivation kinetics for L. monocytogenes, and a new method was developed to calculate the lethality under dynamic conditions. A mathematic method was developed to validate the new model. NP 108 Food Safety 2006-2010 Action Plan Component(s) 1.2.4 Processing Intervention Strategies.

Comparison of palmitic acid and 2-dodecylcylcobutanone clastogenicity and cytotoxicity: Palmitic acid, a saturated fatty acid in meat, is considered to be a strong inducer of DNA strand breakage, chromosome breakage, and apoptosis in human cells in vitro. Irradiation of palmitic acid leads to the formation of the unique radiolytic product 2-dodeclycobutanone (2-DCB) which is found at levels in meat products. The ability of palmitic acid and 2-DCB to cause DNA breakage in human cells was compared. Both palmitic acid and 2-DCB exhibited a similar toxicity, demonstrating that palmitic acid and 2-DCB had similar DNA strand breakage and cytotoxic profiles. These data will help the FDA evaluate a petition, currently under review, to allow irradiation of ready-to-eat foods and provide information to consumers and consumer groups about unique radiolytic products. NP 108 Food Safety 2006-2010 Action Plan Component(s) 1.2.4 Processing Intervention Strategies.

Ultraviolet light (UVC) inactivation of Shigella sonnie in ice and fish: The bacteria Shigella sonnei has been associated with foodborne illness outbreaks associated with sea foods, and is capable of surviving the freezing process and surviving in ice. Ultraviolet light (UVC) was used to inactivate S. sonnei on the surface of frozen fish, and the ice used to store fish. UVC light inactivated 99% of S. nonnei in ice and on frozen fish surfaces. These data can be used by fish processors to provide safer products for consumers. NP 108 Food Safety 2006-2010 Action Plan Component(s) 1.2.4 Processing Intervention Strategies.

5.Significant Activities that Support Special Target Populations

6.Technology Transfer

Number of new CRADAs and MTAs2
Number of non-peer reviewed presentations and proceedings18
Number of newspaper articles and other presentations for non-science audiences3

Review Publications
Alvarez, I., Niemira, B.A., Fan, X., Sommers, C.H. 2007. Inactivation of Salmonella Enteriditis and Salmonella Senftenberg in liquid whole egg using generally recognized as safe additives, ionizing radiation and heat. Journal of Food Protection. 70(6):1402-1409.

Alvarez, I., Niemira, B.A., Fan, X., Sommers, C.H. 2007. Modeling the irradiation-followed-by-heat inactivation of salmonella inoculated in liquid whole egg. Journal of Food Science. 72(5):M145-M152.

Bari, M.L., Mochida, M., Sommers, C.H., Hayakawa, F., Todoriki, S., Kawamoto, S. 2006. Irradiation inactivation of listeria monocytogenes in low fat ground pork at frozen and refrigerated temperature. Journal of Food Protection. 69:2955-2960.

Fan, X. 2006. Irradiated ground beef for national school lunch program. In Sommers, C.H., Fan. X., editors. Food Irradiation Research and Technology. Ames, Iowa. IFT Press/Blackwell Publishing. p. 237-248.

Fan, X., Mastovska, K. 2006. Effectiveness of ionizing radiation in reducing furan and acrylamide levels in foods. Journal of Agricultural and Food Chemistry. 54:8266-8270.

Fan, X., Sommers, C.H. 2006. Effect of gamma radiation on furan formation in ready-to-eat products and their ingredients. Journal of Food Science. 71(7):C407-C412.

Huang, L. 2007. Numerical Analysis of Survival of Listeria monocytogenes during In- Package Pasteurization of Frankfurters by Hot Water Immersion. Journal of Food Science. 72(5):E285-E292.

Fan, X. 2007. Control of irradiation-induced lipid oxidation and volatile sulfur compounds using antioxidants in raw meat and ready-to-eat meat products. In: Shahidi, F., Ho, C-T., editors. Antioxidant Measurement and Applications. Washington, DC: ACS Symposium Series. p. 401-418.

Last Modified: 4/23/2014
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