SEA gene of Staphylococcus aureus enterotoxin A in fresh cheese

Abstract

Staphylococcus aureus is an enterotoxin-producing microorganism that causes food poisoning, it is transmitted through contaminated food. Objective: To identify the presence of the SEA gene of  Staphylococcus aureus enterotoxin type A in fresh cheeses. Methods and materials: 22 randomly selected samples of fresh cheese were analyzed using microbiological and molecular techniques. Microbiological counts were performed using Baird-Parker agar medium to identify black colonies with transparent halos suspected to be coagulase-positive staphylococci. Phenotypic traits were subsequently identified through biochemical tests in mannitol salt agar, catalase and coagulase tests. Endpoint polymerase chain reaction was conducted for the genotypic characterization of the bacteria, detecting the 16S rRNA gene, in addition to detecting the presence of the SEA gene that encodes the production of enterotoxin type A. Results: Microbiological counts above the permitted limit value were obtained in 18 of the cheese samples (82%). Of the positive isolates for  Staphylococcus aureus by biochemical tests, 63% were confirmed with the 16S rRNA gene, with the SEA gene being identified in 36%. Conclusion: The identification of the enterotoxigenic gene by molecular techniques and the high bacterial contamination is indicative of a risk for the health of the population of suffering from food poisoning or of the presence of other microorganisms that cause foodborne diseases due to the employment of inadequate hygiene practices in the handling and preservation of food.