Abstract:In this paper, antibacterial activity of composite natural preservatives with chitosan, lysozyme, and tea polyphenols against Staphylococcus aureus were investigated. Minimal inhibitory concentration(MIC) and minimal bactericidal concentration(MBC) of composite natural preservatives were determined by stiletto method. The damage of Staphylococcus aureus which treated with composite natural preservatives were studied by cell damage experiment, such as bacteriostatic rate, antibacterial kinetics, growth curve, integrity of cell membrane, alkaline phosphatase(AKP) activity and ultra microstructure of bacteria. It concluded that the MIC and MBC of composite natural preservatives were 0.8mg/mL and 1.6mg/mL. With the extension of time, composite natural preservatives could inhibit the growth of Staphylococcus aureus, increase the quantity of AKP, and destroy the metabolic circulation, make the nucleic acid and protein leaked in cells. When treated with composite natural preservatives, Staphylococcus aureus was distorted, the cell wall was ruptured, the cytoplasm was spilled out, the stability of cell membrane and intracellular environment was destroyed, which led to the death of Staphylococcus aureus.
