Comparison of Conventional and Rapid Methods for Salmonella Detection in Artisanal Minas Cheese

Abstract

Artisanal cheeses traditionally produced from raw milk have a diverse microbiota and, due the varied changes that occur in this type of food matrix during the maturation, pathogens detection’s may be impaired. In this study, the conventional method established by ISO 6579:2005 to evaluate the presence of Salmonella was compared with two alternative rapid methods, PCR-BAX ® (DuPont) and VIDAS ® - SLM (BioMérieux), to analyze artisanal Minas cheese, a typical Brazilian product. Salmonella was not detected by conventional or PCR-BAX ® in 63 artisanal Minas cheese samples analyzed. Although highly specific and accurate, the immunoassay (VIDAS ® -SLM) presented 3.17% of false positives. Good manufactures practices were absent in some producers of Minas artisanal cheese and, the fact of Salmonella was not detected in analyzed samples should be related with presence of high and diverse endogenous microbiota, including approximately, 10 7 CFU.g -1 of lactic bacteria, and a low pH and water activity, conditions that can minimize pathogens growth, provide cellular injury and hamper the recovery strategies.