Occurrence of Listeria monocytogenes, total coliforms, Escherichia coli, and production and storage processes of raw milk from dairy farms in the state of São Paulo, Brazil

Abstract

In the present study, the occurrence of Listeria monocytogenes, total coliforms and Escherichia coli in refrigerated raw milk from 75 dairy farms distributed in three regions (São Carlos - A, Pirassununga - B, and Piracicaba - C) of São Paulo State, Brazil was assessed. The production and storage conditions as well as milking procedures of raw milk were also evaluated. The analysis of L. monocytogenes was performed according to the method established by the Food and Drug Administration (FDA). The Official Method was used for the analysis of coliforms using the SimPlate system. L. monocytogenes was not isolated from raw milk samples (n=286), although Listeria innocua has been isolated in the milking environment. Total coliforms counts above 103 MPN/mL were found in 86% (n=85), 75% (n=71) and 72% (n=66) of samples from regions A, B and C, respectively. E. coli was found in 66% of samples in region A, 65% in region B and 46% in region C. Of the 75 farms surveyed, 77.3% showed inadequate conditions for milk production as well as insanitary milking equipment and utensils which certainly compromises the quality of milk and dairy products.