Genomic study of the cereolysin A and B genes in Bacillus cereus isolated from raw and pasteurized milk

Abstract

Bacillus cereus spores are expanded in the nature and they can be separated from different foods. Cytotoxin is one of the most important poisons which is produced by Bacillus cereus , and it is highly resistant to heat and leads to diarrhea, nausea and vomiting syndrome. Hence study about existence of Bacillus cereus in pasteurized milk is very important due to probability of causing illness by Cereolysin gene products. Therefore, Different milk samples were collected from raw milk to pasteurized milk after various stages of producing pasteurized milk. Cultivation of milk samples in Mannitol egg yolk polymyxin B (MYP) media was done and it was followed by a purification of the observed colonies and investigation of cereolysin A and B by polymerase chain reaction (PCR) amplification. Thus, the gene was amplified and aligned with the previous sequences that were registered in the gene bank database. As such, many new missense mutations were observed at the amplified gene sequences. However these missense mutations caused a change in the sequence of amino acid at the protein chain but the protein efficiency and structure was not changed due to the substitution of amino acids with the same properties. Key words : milk- cereolysin - Bacillus cereus- polymerase chain reaction- gene.