Controlling Listeria monocytogenes, Campylobactor jejuni, Salmonella enterica Typhimurium and Escherichia coli O157:H7 in Meat Products by Irradiation Combined with Modified Atmosphere Packaging
Four of the bacterial pathogens that are of major concern to the meat industry, Listeria monocytogenes, Campylobacter jejuni, Salmonella enterica Typhimurium and Escherichia coli O157:H7 were studied for their susceptibility to high carbon dioxide atmospheres during irradiation and storage by utilizing high-carbon-dioxide modified atmosphere packages (MAP) compared to vacuum packaging. Frankfurters and cooked pork chops (L. monocytogenes), chicken breasts (C. jejuni and S. enterica) and ground beef (E. coli O157:H7) were inoculated with the respective pathogens, packaged in vacuum or MAP and irradiated with doses appropriate to each pathogen. Surviving bacteria were monitored during refrigerated and temperature-abused storage. While irradiation was very effective for reducing the number of pathogens on each product, the use of high carbon dioxide atmosphere in MAP did not increase the effectiveness of irradiation as an antimicrobial treatment. The MAP treatment resulted in less recovery of L. monocytogenes than vacuum for cooked pork chops during refrigerated storage, and for E. coli O157:H7 on ground beef when exposed to room temperature, but not for the other pathogens or products. Consequently, while irradiation is a very effective means of reducing or eliminating bacterial pathogens on meat products, the addition of a high-carbon dioxide MAP system during storage of the products did not greatly improve the control of these pathogens.