Evaluation of diagnostic polymerase chain reaction (PCR) for the detection of Escherichia Coli, Staphylococcus aureus and Bacillus cereus in cheese

Polymerase chain reaction (PCR) assay was used to detect pathogenic bacteria in white cheese samples using suitable primers which are based on specific genes. A total of 70 samples of white cheese were collected from different parts of Baghdad for detection of the pathogens, Escherichia coli, Staphylococcus aureus and Bacillus cereus. Cheese was made ​​locally from different sources of milk (buffalo, cows and sheep). Samples were cultured in liquid enrichment medium (Nutrient Broth) and incubated at 37°C for a period of 16-20 h. DNA was extracted by kit extraction and pathogens were diagnosed. Multiplex polymerase chain reaction was used with primers targeting specialized sites of the target gene in one reaction and the results showed the presence of E. coli (87%), S. aureus (20%) and B. cerues (18%). The results of this study revealed that PCR was a rapid and useful tool for detection of pathogenic bacteria in cheese. Key words: Cheese, polymerase chain reaction (PCR), Escherichia coli, Staphylococcus aureus, Bacillus cereus.