Submitted to: Journal of Food Protection
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: December 19, 2010
Publication Date: April 1, 2011
Citation: Sommers, C.H., Niemira, B.A. 2011. Inactivation of avirulent Yersinia pestis in beef bologna by gamma irradiation. Journal of Food Protection. 74(4):627-630. Interpretive Summary: Yersinia pestis (Y. pestis) is the bacteria that causes plague, and is a microorganism of food safety and food security concern. This microorganism can grow in the refrigerator on products such as bologna. Ionizing (gamma) radiation is a safe and effective technology that can inactivate Y. pestis in foods. In this study we determined the radiation resistance of a virulent Y. pestis in beef bologna at different temperatures, and developed a predictive equation to describe the effect of temperature and radiation dose on the survival of a virulent Y. pestis. Gamma radiation would be an effective technology for control of this pathogen in emulsion sausage products such as bologna. These results provide the necessary information for governmental agencies and the food and radiation processing industries to control Y. pestis in ready-to-eat products if the need ever arose.
Technical Abstract: Yersinia pestis, a psychrotrophic pathogen capable of growth at refrigeration temperatures, can cause pharyngeal and gastrointestinal plague in humans as a result of eating contaminated foods. Because Y. pestis is listed as a select agent for food safety and defense, evaluation of food safety intervention technologies to inactivate this pathogen are desired. Ionizing (gamma) radiation is a safe and effective intervention technology that can inactivate pathogens in raw and processed meats, produce, and seafood. In this study we investigated the effect of temperature on the ability of ionizing radiation to inactivate avirulant Y. pestis in beef bologna. The radiation D-10 (the radiation dose needed to inactivate 1 log of microorganism) of avirulent Y. pestis suspended in beef bologna were 0.20 (+/-0.01), 0.22 (+/-0.01), 0.25 (+/-0.02), 0.31 (+/-0.01), 0.35 (+/-0.01) and 0.37 (+/-0.01) kGy at temperatures of 5, 0, -5, -10, -15, and -20 degrees C, respectively. When incorporated into a 3D mesh, the predictive equation followed a parabolic fit (R(2)=0.84) where log10 reduction = - 0.264 - (0.039 x Temp) - (3.833 x Dose) - (0.0013 x Temp(2)) - (0.728 x Dose(2)). These results indicate that ionizing radiation would be an effective technology for control of this pathogen in ready-to-eat fine emulsion sausage products.