Evaluation of Enterotoxins and Antimicrobial Resistance in Microorganisms Isolated from Raw Sheep Milk and Cheese: Ensuring the Microbiological Safety of These Products in Southern Brazil

Abstract

This study emphasizes the importance of monitoring the microbiological quality of animal products, such as raw sheep’s milk and cheese, to ensure food safety. In Brazil, there is currently no legislation governing the quality of sheep’s milk and its derivatives. Therefore, this study aimed to evaluate: (i) the hygienic-sanitary quality of raw sheep’s milk and cheese produced in southern Brazil; (ii) the presence of enterotoxins and Staphylococcus spp. in these products; and (iii) the susceptibility of the isolated Staphylococcus spp. to antimicrobial drugs and the presence of resistance genes. A total of 35 samples of sheep’s milk and cheese were examined. The microbiological quality and presence of enterotoxins were accessed using Petrifilm and VIDAS SET2 methods, respectively. Antimicrobial susceptibility tests were conducted using VITEK 2 equipment and the disc diffusion method. The presence of resistance genes tet(L), sul1, sul2, ermB, tetM, AAC(6)’, tetW, and strA were evaluated through PCR. In total, 39 Staphylococcus spp. were obtained. The resistance genes tetM, ermB, strA, tetL, sul1, AAC(6)’, and sul2 were detected in 82%, 59%, 36%, 28%, 23%, 3%, and 3% of isolates, respectively. The findings revealed that both raw sheep’s milk and cheese contained Staphylococcus spp. that exhibited resistance to antimicrobial drugs and harbored resistance genes. These results underscore the immediate need for specific legislation in Brazil to regulate the production and sale of these products.

Keywords

• raw sheep’s milk
• cheese
• staphylococcal enterotoxin
• microbiological safety
• antimicrobial resistance