Effect of modified atmosphere package with varying oxygen concentrations combined with controlled freezing-point storage on pork fresh-keeping

Effect of modified atmosphere packaging with varying oxygen concentrations combined controlled freezing-point storage on pork fresh-keeping was studied. By determining physicochemical parameters such as total plate count, total volatile base nitrogen (TVB-N), drip loss, water holding capacity and color, the qualities of pork under controlled freezing-point storage, chill storage, vacuum package+controlled freezing-point storage, 20%CO2+80%O2 (high oxygen)+controlled freezing-point storage, 20%CO2+20%O2+60%N2 (low oxygen)+controlled freezing-point storage and 20%CO2+80%N2(no oxygen)+controlled freezing-point storage were compared. It showed that total plate count under high oxygen and low oxygen did not exceed the hygiene standard of pork after twenty-four days, and there was no significant difference between them(P＞0.05). High oxygen modified atmosphere package(MAP) and low oxygen MAP maintained the color better. The drip losses of high oxygen MAP and low oxygen MAP after eight days were significantly higher than that of controlled freezing-point storage (P＜0.05) and no oxygen MAP, and the drip loss of high oxygen MAP was significantly higher than that of low oxygen MAP after twelve days (P＜0.05), in addition, the water holding capacity of high oxygen MAP was significantly higher than that of low oxygen MAP after eight days (P＜0.05). Both high oxygen MAP and low oxygen MAP combined controlled freezing-point storage could maintain the favorable color long time and inhibit microorganism reproduce, however, each of them has advantages either in drip loss water or holding capacity.