Effect of different radiation dose rates on refrigerated mechanically deboned chicken meat

Samples of mechanically deboned chicken meat (MDCM) were irradiated while frozen with doses of 0.0 kGy, 3.0 kGy - 4.04 kGy.h-1 and 3.0 kGy - 0.32 kGy.h-1. Individual lots of irradiated and non irradiated samples were evaluated for Substances Reactive to Thiobarbituric Acid (TBARS) and total count of psychotropic bacteria, while in refrigerated storage (2 ±1 deg C), for 11 days. The values for percentage of recovery for 1,1,3,3-tetraetoxipropane (TEP) and for conversion of the K value for samples irradiated with 3.0 kGy - 4.35 kGy.h-1 and 3.0 kGy - 0.3 kGy.h-1 and samples non irradiated were, respectively: 80.3 %, 70.3 % and 80.4 % and 9.1, 11.2 and 9.1. The results showed that there was not a difference for the TBARS values when irradiated and non irradiated samples were compared up to the forth day of refrigerated storage. Between the seventh and eleventh day of storage the TBARS values increased gradually when values obtained for non irradiated and those samples irradiated with doses of 3.0 kGy - 0.3 kGy.h-1 and 3.0 kGy - 4.35 kGy.h-1 were compared. The average values for psychotropic bacteria obtained for samples non irradiated and those irradiated with doses of 3.0 kGy - 0.32 kGy.h-1 and 3.0 kGy - 4.04 kGy.h-1, during the second and eleventh day of frozen storage were respectively 6.68 log (UFC.g-1), 2.87 log (UFC.g-1) and 2.66 log (UFC.g-1). When both variables were evaluated, it was verified that samples irradiated with a dose rate of 0.32 kGy.-1 presented the smallest values of TBARS than those samples irradiated with a dose rate of 4.04 kGy.h-1, from the seventh day of refrigerated storage and bacterial count within the legal limits allowed by the regulation, being considered the best dosage rate for processing MDCM, in the conditions of the present study. (author)