Micro-organismos indicadores e caracterização de Escherichia coli isoladas de leite cru refrigerado

Abstract

The storage of food at low temperatures is the most widely used form of preservation in the production and distribution of fresh food. The practice of storing raw milk refrigerated at the source of production was instituted by the Ministry of Agriculture, Livestock and Food Supply (MAPA) in 2002, aiming to reduce the losses due to the acidifying action of mesophiles. The research of contaminating microorganisms allows the identification of the flaws that lead to the proliferation of these bacterial groups with consequent loss of product quality, and allows the adoption of control measures in order to meet the standards established by the legislation. The objective was to determine the microbiological quality of raw milk from 12 farms located in Pernambuco, Brazil, through quantification of mesophiles and coliforms, which are the micro-organisms of choice for quality control of refrigerated raw milk, whose maximum amounts are established in the current legislation. After quantification and establishment of the cooling effect, 80 isolates of these microorganisms were stocked and passed through molecular tests for genotypic identification of the Escherichia coli strain O157: H7 species. Refrigeration for 24 hours did not interfere with microbial proliferation (P≥0.05) and E. coli O157: H7 was not identified. It is concluded that the milk produced in the properties of three municipalities that compose the milk basin of the state of Pernambuco presents low microbiological quality, which can result in harm to the producers.