Effect of gamma irradiation on the microbial load and chemical and sensory properties of locally prepared fast meals

Locally prepared meals (kubba, borak, cheese borak and sheesh tawoq) were treated with 2, 4 or 6 kGy doses of gamma irradiation. Treated and untreated samples were kept in a refrigerator (1-4 deg. C). Microbiological and chemical analyses were performed on each treated sample immediately after processing, and weekly throughout the storage period, which lasted for 3 weeks for kubba, 6 weeks for borak and cheese borak and 20 weeks for sheesh tawoq. Sensory evaluation and proximate analysis were done within one week after irradiation. Results of the proximate analysis of borak, cheese borak and sheesh tawoq showed that the irradiation doses did not have a significant effect on the moisture, protein and fat contents of meals, whereas for kubba, irradiation decreased the moisture, protein and fat contents. The doses of gamma irradiation selected decreased the microorganism load and increased the shelf life of all meals studied. The radiation doses required to reduce Salmonella and Escherichia coli by one log cycle (D₁₀) in borak were 0.46 and 0.51 kGy, in cheese borak 0.30 and 0.50 kGy and for sheesh tawoq 0.44 and 0.39 kGy, respectively. The three chemical parameters, total acidity, lipid peroxide and volatile basic nitrogen, which were chosen as the indices of freshness, were all well within the acceptable limit for up to 3 weeks for kubba, 6 weeks for borak and cheese borak and 20 weeks for sheesh tawoq treated with 6 kGy. Sensory evaluation showed no significant differences between irradiated and non-irradiated samples. (author)