Submitted to: Journal of Food Science and Technology
Publication Type: Peer reviewed journal
Publication Acceptance Date: 12/18/2008
Publication Date: 3/10/2009
Citation: Liu, Y., Ream, A.R. 2009. Sporulation and germination gene expression analysis of Bacillus anthracis Sterne spores in skim milk under heat and different intervention techniques. Journal of Food Science and Technology. 74(3):120-124. Interpretive Summary: The spore-forming bacterium Bacillus anthracis is an important pathogen that causes anthrax in humans and animals. B. anthracis spores could be used as biothreat agents and released purposely in milk. In order to enhance milk safety against purposely contamination with a bioterrorist attack, it is necessary to study the behavior of B. anthracis spores in milk. To investigate how B. anthracis spores survive in milk, real-time reverse transcriptase- polymerase chain reaction (RT-PCR) assays were used to study the sporulation and germination related gene expression under heat, pasteurization, and pasteurization plus microfiltration. Information from this study will help understanding how B. anthracis spores survive in milk, eventually aid developing new intervention strategies to control this bacterium in food.
Technical Abstract: To investigate how B. anthracis Stene spores survive in milk under heat (80 degree C, 10 minutes), pasteurization (72 degree C, 15 seconds) and pasteurization plus microfiltration, the expression levels of genes that related to sporulation and germination were tested using real-time PCR assays. Twenty seven sporulation and germination-related genes selected from transposon insertion mutations were selected for the target genes. RNA was isolated from the spores in milk after heat, pasteurization and pasteurization and microfiltration and subject to real-time PCR assays. Our results demonstrated that gene expression levels were altered by heat whereas the pasteurization, microfiltration and pasteurization caused less alteration in gene expression. Heat activates and inhibits both sporulation- and germination-related genes, suggesting that bacterial spores underwent different molecular mechanism for heat treatment. Our results may provide some insight to the molecular mechanism of spore survival under different intervention strategies.