ARS | Publication request: INACTIVATION OF PATHOGENS IN COMPLEX READY-TO-EAT FOODS USING GAMMA IRRADIATION

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: September 1, 2005
Publication Date: September 17, 2005
Citation: Alvarez, I., Niemira, B.A., Fan, X., Sommers, C.H. 2005. Inactivation of pathogens in complex ready-to-eat foods using gamma irradiation [abstract]. Institute of Food Technologists Nonthermal Processing Division Workshop. p.1.

Technical Abstract: Foodborne illness outbreaks and product recalls are occasionally associated with ready to-eat (RTE) sandwiches and other “heat and eat” multi-component RTE products. Ionizing radiation can inactivate foodborne pathogens on raw meat and poultry, fruits and vegetables, seafood, and RTE meat products. However, less data is available on the ability of low dose ionizing radiation, doses under 5 kGy typically used for pasteurization purposes, to inactivate pathogenic bacteria on complex multi-component food products. In this study the ability of ionizing radiation to inactivate Salmonella spp., Listeria monocytogenes, Staphylococcus aureus, Escherichia coli O157:H7, and Yersinia enterocolitica on RTE foods including a “frankfurter on a roll”, a “beef cheeseburger on a bun” and a “vegetarian cheeseburger on a bun” was investigated. The individual bacterial species (three isolate mixtures) were surface-inoculated (8 log10 CFU/g) onto each of the product types, irradiated (Cs-137 self-contained irradiator, 0.095 kGy/min, 4C, aerobic environment), and the surviving bacteria enumerated by standard microbiogical techniques for determination of D-10 value. The average D-10 value, the radiation dose needed to inactivate 1 log10 of pathogen on the three products, were 0.61, 0.54, 0.47, 0.36 and 0.15 kGy for Salmonella spp., S. aureus, L. monocytogenes, E. coli O157:H7, and Y. enterocolitica, respectively. A low radiation dose of 1.25 kGy was able to inactivate >2 log10 of Salmonella spp., the most radiation resistant of the pathogens tested, on each of the three products tested, while a radiation dose of 2.5 kGy was able to inactivate > 4 log10 of Salmonella spp. These results indicate that irradiation may be an effective means for inactivating common foodborne pathogens including Salmonella spp, S. aureus, L. monocytogenes, E. coli O157:H7 and Y. enterocolitica in complex RTE food products such as “heat and eat” sandwiches.