Environmental Stresses Tolerance and Biofilm Control of Cold Induced Staphylococcus aureus

In order to study the effect of cold induction on other environmental stress tolerance of Staphylococcus aureus, the S. aureus W3 which had strong resistance to freezing and standard strain S.aureus CICC10201 were measured at high temperatures, pH, NaCl, hydrogen peroxide and alcohol after 5 h of cold stress at 4℃. Meanwhile, the biofilm formation ability and control method were studied. The results showed that after 8 weeks of storage at -20℃, the survival rate of S.aureus W3 was significantly higher than that of S.aureus CICC10201 (p<0.05). After cold induction, the survival rates of S. aureus W3 increased by 18.5% at 45~60℃. Cold induction enhanced the sensitivity of S. aureus to acidic environment, but it produced cross resistance to alkaline environment. After cold induction, the survival rate of two strains in hypertonic environment decreased, and the lowest decreased by 24.09%. In addition, the tolerance of S. aureus to alcohol increased after cold induction. For hydrogen peroxide, there was no significant (p>0.05) change in the tolerance of S.aureus W3 before and after induction. But the sensitivity of the S.aureus CICC10201 was enhanced after cold induction, and the survival rate decreased. S.aureus W3 has stronger biofilm formation ability than S.aureus CICC10201, and 1% 84 disinfection can effectively remove its biofilm. This study provides a theoretical basis for the safety control of S. aureus in frozen foods.