Irradiation to ensure the safety and quality of some ethnic soups, snacks and Yunan chicken

Semi-concentrated black, oxtail, chicken vegetable and chicken sweetcorn soups, precooked spring roll, rissole and croquette snacks, and Yunan chicken were individually packed in a dry laminate pouch of PET 12 μm/LDPE adh.2 μm/Al foil 7 μm /LDPE adh/LLDPE (C4) 50 μm under vacuum followed by freezing for 24 h at -18 deg. C prior to irradiation with doses of 1, 3, 5 and 7 kGy at cryogenic conditions (-79 deg. C). Both the non-irradiated and irradiated prepared meals were then stored in a refrigerator at 5 ± 2 deg. C. The non-irradiated samples and those samples irradiated at 1 kGy were mostly damaged after a week in storage. Gamma irradiation at doses of 5-7 kGy for soups and snacks, and doses of 3-5 kGy for Yunan chicken can reduce the microbial load by about 2-3 log cycles, respectively, without affecting the physicochemical parameters and palatability over 2-3 months. However, the irradiated spring roll was unable to withstand more than 1 month storage. The D₁₀ values for potential pathogens on Yunan chicken were 0.28 kGy for Salmonella typhimurium, 0.17 kGy for Pseudomonas aeruginosa, 0.12 kGy for Escherichia coli O157, 0.66 kGy for Listeria monocytogenes and 0.09 kGy for Campylobacter jejuni. (author)