Submitted to: Journal of Food Protection
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/11/2006
Publication Date: N/A
Interpretive Summary: Salmonella contamination of egg and liquid whole egg products is a frequent cause of foodborne illness in the U.S. Both ionizing radiation and heat treatments can both inactivate Salmonella in liquid whole egg, however, excessive use of either damages the quality of the egg product. In this study the use of a low dose of ionizing radiation (0.1 kGy) reduced the time and temperature heat treatments typically used by the egg industry to obtain a 99.999 percent reduction of Salmonella between 30 and 86 percent. Use of the irradiation and heat procedure would enable the egg processing industry to provide safer liquid whole egg products to consumers.
Technical Abstract: Salmonella is a frequent contaminant on eggs and is responsible for foodborne illnesses in humans. Ionizing radiation and thermal processing can be used to inactivate Salmonella in liquid whole egg (LWE), but the technologies are only partially effective in reducing Salmonella populations when restricted to doses that do not affect LWE quality. In this study the use of ionizing radiation in combination with thermal treatment on the survival of Salmonella serovars was investigated. Salmonella Senftenberg was the most radiation and heat resistant (D-Gamma = 0.65 kGy, D-55 C = 11.31, z = 4.9 C) of the six Salmonella serovars tested. Irradiation followed by heat at 55 or 57 C improved the pasteurization process. Radiation doses as low as 0.1 kGy prior to thermal treatments synergistically reduced the D-55 C and D-57 C of Salmonella Senftenberg 3.6 and 2.5 fold, respectively. The D-55 C and D-57 C of Salmonella Typhimurium was reduced 2 and 1.4 fold, and those of Salmonella Enteritidis 2 and 1.6 fold. Irradiation prior to thermal treatment would enable the reduction of heat treatment times by 86 percent and 30 percent at 55 and 57 C, and would theoretically inactivate 9-log10 of Salmonella serovars.