| The limited shelf life one of the main obstacles that hinder the further development of chilled meat.The chilled pork is used as experimental materials,and the major spoilage bacteria of chilled meat is isolated and identified in the paper.The composition of the initial micro organism and changes of micro organism during storage is also analyzed.The bacteria inhibition activities of some natural preservative are compared and the composition of a sort of combined preservative is optimized.The effectiveness and mechanism of the combined preservative on the shelf-life of chilled meat is studied by the further experiment.1.The major micro organism causing the spoilage of chilled pork is isolated and identified.The experimental results showed that spoilage bacteria of chilled pork are Pseudomonas,Enterbacteriaceace,Lactic acid bacteria and Staphylococcus aureus.The dominant bacteria in the initial count was Pseudomonas.So we can have a definite object in method of raked preservative.The goal is adopt further measure to protect the chilled pork more effectively,and prolong the shelf life of the chilled pork.2.The minimum inhibition concentration for bacteria and the strength of inhibit effect of tea polyphenols,lysozyme,clove and cassia are studied by inhibition experiment.The experimental results showed that tea polyphenols were very strong inhibition effect for the bacteria causing the spoilage of chilled pork.The minimum inhibition concentration of tea polyphenols was 0.5%.Lysoxyme was stronger inhibition effect for Gram positive bacteria. But it was feeble or non inhibition effect for Gram negative bacteria.The minimum inhibition concentration of lysoxyme was 0.015%.The clove and cassia were extensive inhibition effect.The minimum inhibition concentration of them was 5.0%.3.The properties of tea polyphenols,lysozyme,clove and cassia are studied.Three factors quadratic general design is applied by the properties of the main bacteria causing the spoilage of chilled pork in the experiment.Regress equation ((?)=0.03+0.000 4 x1+0.004 5 x2+0.006 2 x3-0.000 8 x1 x2 -0.003 8 x1x3+0.002 3 x2x3 -0.000 2 x12+ 0.002 1 x22+0.0027 x32)is effective.The three factors have synergetic effect.So the optimized composition of a sort of combined preservative:clove and cassia is 5.0%, lysozyme is 0.025%,tea polyphenols is 1.0%.4.The effect of the optimized composition of a sort of combined preservative and shelf life of chilled pork protracted are studied in the lower initial bacteria count (＜103～104cfu/cm2).The experimental results showed that the combined preservative has strong inhibition effect for the spoilage bacteria of chilled pork,the initial bacteria count on the surface of chilled pork.At the end of storage,the value of TVB-N,drop loss and pH are all lower than the goal requirement.
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