Detection of Brucella spp., Campylobacter spp. and Listeria monocytogenes in raw milk and cheese of uninspected production in the metropolitan area of São Paulo

Abstract

Foodborne diseases are a major public health issue but their overall incidence is underestimated due to insufficient report. The present study aimed to investigate the presence of Brucella spp., Campylobacter spp. and Listeria monocytogenes in raw milk and cheese of uninspected production obtained from cattle bred on the polluted banks of the Tietê River. Generally, milk from these animals is used to prepare fresh cheese, which is then commercialized by the producers themselves or in local markets. We analyzed 81 samples consisting of 38 samples of cheeses, 15 samples of raw milk and 28 samples of water collected from the Tietê River. These samples were evaluated for the presence of the three pathogens using bacteriological methods and the conventional polymerase chain reaction (PCR), with primers specific for each bacterial genus. In the bacteriological examination, all samples were negative for Brucella spp., Campylobacter spp. and Listeria monocytogenes. In the PCR test, Brucella spp. was detected in 5/38 (13.16%) cheese samples. Campylobacter spp. was present in 18/38 (47.37%) cheese samples, 1/15 (6.66%) raw milk samples and in 12/28 (42.86%) water samples. Listeria monocytogenes was not detected by PCR. The detection of Brucella spp. DNA in cheese and Campylobacter spp. DNA in cheese, milk and water may reflect inadequate animal sanitary management and deficiencies in good manufacturing practices. The presence of these pathogens in the food and water may pose a threat to the health of the consumer and increase the incidence of zoonosis.