QUANTITATIVE RISK ASSESSMENT FOR STAPHYLOCOCCAL ENTEROTOXIN TYPE A POISONING DUE TO CONSUMPTION OF MINAS FRESCAL CHEESE IN BRAZIL

Among the enterotoxigenic staphylococci, Staphylococcus aureus is the most relevant species. Raw milk has a complex natural microbiota in which the Staphylococcus genus is part, and its concentrations are increased in cases associated with mastitis. In Brazil, one of the most popular types of cheese is Minas Frescal cheese (MFC), which there are reports of outbreaks involving S. aureus and its related toxins. This study aimed to estimate the risk of poisoning by staphylococcal enterotoxin type A (SEA) due to consumption of Minas Frescal cheese (MFC) in Brazil. A Quantitative Microbiological Risk Assessment (QMRA) model was developed with a focus on SEA production in raw milk, associating the S. aureus count with the occurrence of mastitis in dairy cattle. The model was divided into milk, cheese making, and consumption modules, and simulations were carried out with parameter variations such as the probability of occurrence of toxin genes and concentration of S. aureus in raw milk. The baseline scenario yielded an average SEA concentration in the MFC portion of 15.76 ng. The most critical scenario was observed when the toxin genes probability of 1 was evaluated, yielding a SEA concentration of 88.8 ng. The concentration of S. aureus in raw milk proved to be the most influential parameter in the output, followed by the probability of toxin genes and serving size. In the most conservative approach to estimating the number of cases, more than seven million cases were predicted when the concentration of S. aureus was set at 6 log CFU/mL, while the baseline scenario predicted around 4.4 million cases. Prevalence, processing, and consumer surveys, in addition to the obtained risks, are essential for identifying the critical stages of the MFC production chain, enabling the development of actions aimed at the main points where the emergence of risks is favored.