Improvement of microbiological quality of hen egg powder using gamma irradiation

Abstract

Eggs and their products such as desserts, confectioneries, bakery mixes, mayonnaise and many convenience foods have been implicated in food-borne disease outbreaks due to microorganism contamination. The effect of gamma irradiation on the presence of microorganisms in egg powder was investigated. Egg powder samples were exposed to several doses of irradiation: 0, 5, 10 and 15 kGy and stored for up to 12 months at ambient temperature (25 ^oC). Results indicated that the total viable count (TVC) (5.56 log₁₀ cfu g^-1), total coliform counts (TCC) (6.46 log₁₀ cfu g^-1) and mold and yeast counts (MYC) (9.12 log₁₀ cfu g) in un-irradiated (control) samples of egg powder were higher than the maximum limits (4.88, 2.00 and 1.70 log₁₀ cfu g^-1, respectively). Application of the higher doses (10 and 15 kGy) decreased the TVC, TCC and MYC of the egg powder samples to less than 1 log₁₀ cfu g^-1 and the counts remained almost constant during storage for 12 months. D₁₀ values for Escherichia coli and Salmonella typhimurium were 0.714 and 0.278 kGy, respectively. Gamma irradiation treatment could be chosen on the basis of preliminary microbiological tests including TVC, TCC and MYC and help improve the hygienic quality by killing and reducing the microorganisms that might be present inside of egg powder to meet national and international standards.