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. Key words: Brucella spp. Campylobacter spp. Listeria monocytogenes. Informal cheese production. Milk. ResumoAs doenças transmitidas por alimentos (DTA) ainda são subnotificadas, sendo difícil estimar a incidência global. O presente estudo objetivou detectar a presença de Brucella spp., Campylobacter spp. e Listeria monocytogenes em queijo de produção informal e leite cru, provenientes de bovinos criados às margens poluídas do Rio Tietê. O leite desses animais era utilizado na preparação de queijos tipo frescal, comercializados pelos próprios produtores ou no comércio local. No total, 81 amostras foram analisadas: 38 de queijos, 15 de leite cru e 28 alíquotas de água do Rio Tietê. Os materiais foram processados por métodos bacteriológicos e pela reação da polimerase em cadeia (PCR) convencional,