Abstract:The tolerance ability of 15 Cronobacter sakazakii isolates with different genotypes that recovered from powdered infant and baby formula (PIBF) and baby rice cereal (BRC) to different temperature, pH, and microwave, and the susceptibility to Mamiai and lactobacillus-producing lactobacillus was studied to perform some reference for infant and baby food safety. Plate counting method was employed to calculate the survival rate, which was used as the index to evaluate the tolerance ability of the bacteria, after heat, pH and microwave treatment. The rate of the diameter of the inhibition zone and the cup that put the anti-bacteria or the width of the inhibition zone to Cronobacter sakazakii was used to evaluate the susceptibility of Cronobacter sakazakii to Live Combined Bacillus Subtilis and Enterococcus Faecium Granules with Multivitamines (Product name: Mamiai) and lactobacillus. Results: The survival rate of 15 Cronobacter sakazakii isolates indicated the lethal effect of 70 ℃ was significantly higher than those of 50 ℃ and 60 ℃ (P<0.01). The survival rates were all less than 0.11% after the isolates were treated at 70 ℃ for 20 min. A certain lethal effect was shown after treated on condition of pH 4.0, pH 6.0 and pH 8.0 for 20 min, and the survival rate of pH 4.0 treatment was significantly lower than those of the other two groups (P<0.01). The mortality rate of majorities of the tested strains was as high as 99% after treated by microwave for 2 min, and no significant difference was found among the survival rate of the strains(P>0.05). Lactobacillus-producing lactobacillus and Mamiai had a certain degree of inhibition to Cronobacter sakazakii, and the susceptibility of some strains was significant different (P<0.01). Conclusion: The tolerance and susceptibility of the Cronobacter sakazakii strains were different, appropriate methods could be taken to prevent Cronobacter sakazakii contamination from infant and baby foods.