Avaliação das condições higiênico-sanitárias de leite in natura, após processamento térmico e pesqueisa de alguns patógenos

Abstract

Milk is considered a nutritious food, due it composition, with protein, vitamins and mineral salts and could be consumed as cheeses, yogurts, butter and desserts. However, it can be vehicle of several pathogenic bacteria as L. monocytogenes, Campylobacter jejuni, E. coli O157: H7, Salmonella sp and S. aureus. Those microorganisms can contaminate the milk in any production stage, improvement, distribution and consumption. The aim of this study was search the hygienic condition of milk in several stages, as the raw milk, pasteurized and in the validity date, through the determination of the Most Probable Number of thermotolerants coliforms, besides the research of the presence of Salmonella and Listeria and enumeration of Staphylococcus aureus and its genes encoded A, B, C, D, E, G, H, I and J enterotoxins. Among 54 raw milk samples, all of them presented thermotolerants coliforms, invalue that varied from 2.1 x 102 MPN/ml to 1.1 x 106 MPN/ml. S. aureus was present in 38 (70.4%) of those samples, in values of up to 8,9 x 105 CFU/ml. About Listeria sp presence, using the traditional methodology, 16 samples were positive (29.6%) and 7 were L. monocytogenes (13% of the total of samples). PCR technique detected L. monocytogenes in 12 samples (22.2%). Analyzing 54 samples of milk pasteurized, 18 (33.3%) were out of the patterns according to RDC N°12, in relation to the number of thermotolerants coliforms, witth values up to 1,5 x 102 MPN/ml. Five samples (9.3%) reveled the presence of Listeria sp, with 3 L. monocytogenes (5.6%) and 2 L. innocua (3.7%). S. aureus was observed in 8 (14.7%) of the 54 samples, in concentration up to 8.7 x 103 CFU/ml. Of the 54 pasteurized milk in the validity date, 32 (59%) were in disagreement with the patterns, reaching values up to 2.1 x 102 MPN/ml of thermotolerants coliforms. Listeria sp was detected em 10 samples (18.5%), and 4 were L. monocytogenes and L. innocua (7.4%) and three, L. ivanovii (5.6%). Salmonella was...