Studyon The Controlled Atmosprhere Storage Technology Of Fresh Pork

Fresh pork as the raw material is used to study the storage effect through differentpacking material and different gas component. Sense, aerobic plate count, total volatilebasic nitrogen, pH value, and the rate of juice leakage of fresh pork are also tested toevaluate the storage effect of fresh pork during the storage period, and the optimumprocess parameters are obtained by response surface method.（1） The preservation effect of fresh pork with the different packing material byvacuum packing under the same storage condition. The results indicate that thepreservation effect of packing material is as follow: co-extruded bags （9s）> co-extrudedbags （12s）> composite bags （9s）> composite bags （12s）> ordinary bags. In the sensoryevaluation, co-extruded bags （9s） are better than the other four packing materials. Theaerobic plate count, total volatile basic nitrogen and the rate of juice leakage of theco-extruded bags （9s） are obviously lower than that of the control group, and slightly lowerthan that of the other three groups. Therefore, the co-extruded bags （9s） are picked as thepacking material in the later experiments.（2）The preservation effect of fresh pork by the different gas component was studied.The optimum concentration of O₂and CO₂for the better preservation effect of fresh porkwas obtained by the single factor experiment. N2as the filling gas, the different oxygenconcentrations, which are30%，40%，50%，60%，70%, respectively, are used to study thepreservation effect of fresh pork. The experimental results show that the color of fresh porkis steadied and satisfied in the15d test when the O₂concentration is60%and70%.However, its APC values and TVB-N values are a little higher, the microbiologicalindicator and physicochemical property are better than the results of the tests as the O₂concentration of40%and50%, its sensory index is also satisfied. In the modified CO₂concentration （10%,20%，30%，40%and50%） experiment， the result shows that CO₂begins to has antibacterial effect to fresh pork when its concentration reaches to20%andThe antibacterial effect gets to the best as the CO₂concentration is40%and50%, as wellas its sensory value, there is no obviously difference between them. pH value is no changeand the rate of juice leakage is low when the CO₂concentration is20%and30%.（3）Based on the single factor experiment, the orthogonal experiment is done under theO₂concentration of40⁶0%and CO₂concentration of20⁴0%to get the optimumconcentration of gas mixtures. According to the orthogonal experiment, the optimumcondition of modified atmosphere packing for the fresh pork preservation is A2B3C1,which is50%O₂concentration,40%CO₂concentration and0.06MPa vacuum degree. Keepgood sense value, resist the microbiological spoilage, reduce the produce of TVB-N, andkeep steady of pH value during the process of pork storage under this condition, which also can improve the quality and prolong the shelf life of fresh pork.