Abstract

OCCURRENCE OF ESCHERICHIA COLI AND STAPHYLOCOCCUS AUREUS IN ARTISANAL MINAS FRESH CHEESES PRODUCED IN THE RURAL AREA OF THE BAIXADA FLUMINENSE REGION, PROVINCE OF RIO DE JANEIRO, BRAZIL

Gisele Ferreira Fonseca, Aluízio Antonio de Santa Helena, José Tadeu Madeira de Oliveira, Jaqueline Santos Andrade Martins, Bianca Magnelli Mangiavacchi, Paulo Roberto Blanco Moreira Norberg, Antonio Neres Norberg*

ABSTRACT

Consumption of from raw milk-derived products contaminated by pathogenic microorganisms is one of the main sources of foodborne infections. The aim of this research is to investigate and quantify the contamination by bacteria in artisanal Minas fresh cheese produced in the rural area of the Baixada Fluminense region, Province of Rio de Janeiro, Brazil. The research was performed with 10 cheese samples from different origins for the investigation of contamination by Staphylococcus aureus and thermotolerant coliforms represented by Escherichia coli. For the counting of bacteria in the samples, the evaluation technique was the process of counting Colony Forming Units (CFU) per mL. The serum leaked from the cheeses samples was diluted in sterile saline in concentration factors multiple of 10. Aliquots of the dilutions were seeded in Petri dishes containing: hypertonic mannitol agar, Teague and Mueller-Hinton agar. The plates with the culture media were incubated at 37oC for 48 hours. The CFU count was performed on plates where the counting of isolated colonies was possible. Staphylococcus aureus and Escherichia coli were identified by cultural characteristics, biochemical and biological evidence. All 10 samples analyzed were contaminated with S. aureus and in five of these samples the number of CFU was above the limits accepted by Brazilian legislation, and for thermotolerant coliforms, represented by E. coli, all 10 samples had a CFU count. per mL above that tolerated by legislation. The ingestion of artisanal cheese produced in the studied region carry pathogenic microbial elements, besides toxins which cause food poisoning.

Keywords: Fresh cheese, foodborne toxinfection, contaminated food, Staphylococcus aureus, Escherichia coli.