The eradication of Salmonella in egg powder by gamma irradiation

Abstract

The contamination of whole egg powder with salmonellae was investigated in suspected samples. They were found to contain between 0.1 and 0.01 CFU/g of S. Lille, S. enteritidis, and S. typhimurium. The radiation resistance of these strains was investigated in artificially inoculated whole egg powder. The decimal reduction dose (D10) 0.8 kGy was obtained for a mixture of the three strains. A reduction factor of 103 can therefore be accomplished by irradiation with 2.4 kGy. While this may be adequate in many cases, higher reduction factors may also be desirable. They are obviously possible with a higher dose of radiation, or, alternatively, by following low-dose irradiation with post-irradiation storage. For example, irradiation with 1 kGy followed by 3 weeks' storage is approximately equivalent to the immediate bactericidal effect of 3 kGy.