Microbial flora of frozen beefburger as affected by gamma radiation

ABSTRACT

Freshly prepared beefburger samples were obtained from a Meat Products Plant in Cairo in frozen state. Samples were irradiated with 5 KGy dose level at the same day of manufacture. Unirradiated and irradiated samples were stored at 18 degrees and analyzed microbiologically during storage up to 12 months for total viable counts of bacteria, yeasts, molds, sporeformers, B. Cereus, Strept. faecalis, Staph. Aureus, fecal coliform as well as the detection of Salmonella and Cl. perfringens. Also, the acid number of extracted beefburger fat and thiobarbituric acid value were assessed. The results indicated that the applied radiation dose resulted in reduction of the total bacterial count, sporeformers and completely inhibited yeasts, molds, Strept. faecalis, Staph. Aureus and fecal coliform but not B. cereus. Salmonella and Cl. perfringens were not detected in beefburger samples. The number of different groups of microorganisms studied decreased as storage period advanced with different rates. The acid value of beefburger fat increased gradually during storage at higher rate in unirradiated samples than irradiated ones, while the TBA value had the reverse. Therefore, it could be concluded that, application of gamma rays with 5 KGy can be used as an additional tool to freezing for eliminating such pathogens as well as reducing the microbial load. More radiation dose are needed for the destruction of B. cereus