Sporulation and germination gene expression analysis of Bacillus anthracis Sterne spores in skim milk under heat and different intervention techniques.

To investigate how B. anthracis Sterne spores survive in milk under heat (80 degrees C, 10 min), pasteurization (72 degrees C, 15 s), microfiltration, and pasteurization and microfiltration, the expression levels of genes related to sporulation and germination were tested using real-time PCR assays. Twenty-seven sporulation- and germination-related genes were selected for the target genes. Our results demonstrated that gene expression levels were altered by heat and microfiltration whereas the pasteurization and pasteurization and microfiltration resulted in less alteration of gene expression. Heat activated and inhibited both sporulation- and germination-related genes, suggesting that bacterial spores underwent different molecular mechanism for heat treatments. Our results may provide some insight into the molecular mechanisms of spore survival in response to heat treatment and different intervention strategies used to treat fluid skim milk.