ENSURING THE SAFETY OF COMPLEX READY-TO-EAT FOODS USING IRRADIATION

Authors: Sommers, Christopher; Boyd, Glenn

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 4/1/2006
Publication Date: 6/28/2006
Citation: Sommers, C.H., Boyd, G. 2006. Ensuring the safety of complex ready-to-eat foods using irradiation. IFT Annual Meeting & Food Expo. Orlando, FL. 6/28/06. p. 1.

Interpretive Summary:

Technical Abstract: Foodborne illness outbreaks and product recalls are occasionally associated with ready to-eat (RTE) sandwiches and other complex RTE food 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 RTE food products. Recent studies have investigated the ability of ionizing radiation to inactivate pathogenic bacteria including 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 studies have included the use of irradiation to inactivate pathogens in an aerobic environment, or in the presence of modified atmospheres. 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) and the surviving bacteria enumerated by standard microbiological 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. The presence of modified atmosphere, 100 percent CO2, 100 percent N2, or a 50 percent mixture of each gas, did not affect the radiation resistance of the pathogens. 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.