Enteroxigenic Staphylococcus spp. and other microbial contaminants during production of Canastra cheese, Brazil

Abstract

Canastra cheese is produced from raw cow's milk, and it is made at the farmhouse level using artisanal procedures and natural starters. The aim of this work was to determine the main hygienic-sanitary indicators and enterotoxigenic staphylococcal strains present during the manufacturing of traditional cheese of Serra da Canastra region, Minas Gerais state, Brazil. Samples from 10 farms were studied, and they included: water employed in the process, raw milk, natural starters, cheese curd before salting and cheese after five days of ripening. All water samples exhibited faecal coliform contamination above the maximum acceptable value recommended by Brazilian standards. Pseudomonas aeruginosa and sulfite-reducing clostridia were also isolated from the water samples. In five samples of raw milk faecal coliform were above the limits allowed by the Brazilian legislation. The counts of Staphylococcus spp. in milk were between <2.0 to 4.9 log.cfu.ml-1. The counts of microbiological indicators were higher in natural starters and curd. High levels of faecal and total coliform, as well as molds, were found in the cheese samples. In all cheeses analyzed Staphylococcus spp. were found in levels above 5.0 log.cfu.g-1. The enterotoxins (SE) most frequently produced by Staphylococcus spp. strains were SEB and SEC. A high number of coagulase negative Staphylococcus strains were also enterotoxin producers. None of the samples contained Salmonella spp. or Listeria spp. These results point out a need for improvements in the production process of the artisanal cheese produced at Serra da Canastra in Brazil.