Physicochemical and microbiological changes in irradiated fresh pork loins

The effect of gamma-irradiation on the physicochemical and microbiological properties of fresh pork was studied. Radiation treatments were carried out under air on fresh pork loins at doses of 2, 4 and 8 kGy and the loins were evaluated for deamidation, solubility, sulphydryl content and surface hydrophobicity. Deamidation was significantly (p less than or equal to 0.05) affected by the treatment with 98% deamidation at a dose of 8 kGy. No significant changes (p > 0.05) were noted in sulphydryl content under the same conditions. The increase in deamidation resulted in a decrease in hydrophobicity and an increase in protein solubility. gamma-irradiation also reduced the number of microorganisms in the meat. Mesophiles were more resistant to the irradiation treatment than psychrotrophs and Pseudomonas. All irradiated pork samples (1 or 3 kGy) had a bacterial count lower that 10(7) CFU/g after 15 days of storage. A minimal dose of 1 kGy was sufficient to increase the shelf life of fresh pork loins although variations in initial pork contamination was found to be the determining factor accounting for the effectiveness of the treatment. (C) 1999 Elsevier Science Ltd. All rights reserved.