EFFECT OF PACKAGING MATERIALS ON INACTIVATION OF PATHOGENIC MICROORGANISMS ON MEAT DURING IRRADIATION

摘要

The effects of packaging materials, low-dose irradiation, and subsequent storage on inactivation of pathogen were studied. UV-sterilized meat surfaces were inoculated with approximately 5 to 6 log ₁₀ CFU/cm 2 E. coli O157:H7 or approximately 6 to 7 log ₁₀ CFU/cm 2 Salmonella Typhimurium, wrapped in plastic sheets of polyethylene, polylactic acid (PLA), polynylon, polypropylene, or low-density polyethylene (LDPE), sealed and vacuum packaged, and subjected to irradiation doses ranging from 0.5 to 2.0 kGy in a 60 Co irradiator. Samples were analyzed for remaining bacterial populations immediately after irradiation and after 7 days of refrigerated storage (4°C). For S. Typhimurium, both the effect of packaging material and storage period were significant as compared to untreated samples (p 0.05). Higher log ₁₀ reductions were observed following irradiation at all doses after refrigerated storage period than for day 0 samples. In general, irradiation resulted in higher log ₁₀ reduction of E. coli O157:H7 than S. Typhimurium at the same dose. The following conditions demonstrated maximum log ₁₀ reductions in this study: 2.0 kGy irradiation dose, 7-day refrigerated storage at 4°C, LDPE plastic for E. coli O157:H7, and PLA plastic for S. Typhimurium. However, there were no significant differences between the mechanical strength of irradiated and unirradiated plastics (p 0.05)