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The aim of this study was to evaluate somatic cell count (SCC), prevalence and etiology of mastitis in a dairy buffalo herd from Analândia, São Paulo State, Brazil, in the dry and rainy seasons. Additionally, antimicrobial susceptibility profile of microorganisms isolated from milk samples was also evaluated. 1,042 milk samples from female Murrah buffaloes in a dairy farm located in Analândia, São Paulo State, Brazil, collected between May 2011 and November 2012 were analyzed. After the mammary gland physical examination, strip cup test and California Mastitis Test (CMT) were performed. Afterwards, 50mL of milk samples from each mammary quarter were collected aseptically for SCC in automatic equipment and microbiological examination. The antimicrobial sensitivity profile to ampicillin, cefoperazone, ceftiofur, enrofloxacin, gentamicin, neomycin, oxacillin, penicillin, and sulfamethoxazole/trimethoprim was evaluated by disk diffusion method. The monthly average temperature and pluviometric index were obtained from "Centro Integrado de Informações Agrometeorológicas" (CIIAGRO) of "Instituto Agronômico de Campinas" (IAC). Milk samples with positive results in the microbiological test showed average SCC of 137,720 cells/mL in the dry period and 190,309 cells/mL in the rainy period. Although a higher number of isolated microorganisms was observed in buffalo milk samples during the rainy period (69/600) compared to the dry period (50/442), the season had no significant effect on the frequency of isolation of microorganisms. The main genera of microorganisms isolated were coagulase-negative Staphylococcus (38.4%), Streptococcus agalactiae (28.8%), and Bacillus spp. (7.56%) during the dry season and Corynebacterium sp. (23.5%), Streptococcus spp. (32.3%), and Streptococcus agalactiae (9.24%) during the rainy period. Multidrug resistance was observed in 30.1% of the isolated microorganisms.

Pesquisaram-se a presença de Bacillus cereus e a produção de enterotoxinas produzidas por esses microrganismos em 120 amostras de diversos tipos de leite. Bacillus cereus foi isolado e identificado em 22 (73,3%), 15 (50,0%), 29 (96,7%) e quatro (13,3%) amostras de leite em pó, cru, pasteurizado e UAT (longa vida), respectivamente. Para a detecção de enterotoxinas pela técnica da alça ligada de coelho, foram positivos, respectivamente, três (13,6%), um (7,1%) e 10 (35,7%) microrganismos isolados das amostras de leite em pó, leite cru e leite pasteurizado. Pelo teste de aumento de permeabilidade vascular, dois (9,1%), um (7,1%), um (3,6%) e um (4,0%) microrganismos isolados de leite em pó, cru, pasteurizado e UAT apresentaram-se enterotoxigênicos, respectivamente. O uso da técnica de aglutinação passiva em látex demonstrou a produção da toxina diarréica por três (33,3%), sete (63,6%), quatro (30,8%) e oito (80,0%) microrganismos isolados, respectivamente, de leite em pó, cru, pasteurizado e UAT. Os resultados indicam um risco potencial, podendo colocar em risco a saúde dos consumidores desses produtos.A hundred and twenty samples of different types of milk were examined to the presence of Bacillus cereus and the enterotoxigenic potential of the isolated strains. Bacillus cereus was isolated and identified in 22 (73.0%), 15 (50.0%), 29 (96.7%) and four (13.3%) samples of powder, raw, pasteurized and UHT milk, respectively. The enterotoxigenicity detection using the rabbit ileal loop assay showed positive, respectively, three (13.6%), one (7.1%) and 10 (35.7%) isolated strains from powder, raw and pasteurized milk. Using vascular permeability activity assay two (9.1%), one (7.1%), one (3.6%) and one (4.0%) isolated strains from powder, raw, pasteurized and UHT milk were positive, respectively. The reversed passive latex agglutination test showed diarrheal toxin production by three (33.3%), seven (63.6%), four (30.8%) and eight (80.0%) strains isolated from, respectively, powder, raw, pasteurized and UHT milk. Those results indicated a potential hazard and may put in risk the health of the consumers of these products.

Cento e dez amostras de 11 diferentes marcas de leite ultra alta temperatura (UAT), comercializadas em São José do Rio Preto - SP, foram submetidas à contagem de microrganismos heterotróficos mesófilos viáveis e à pesquisa de bactérias do grupo do Bacillus cereus. A população de microrganismos mesófilos variou de ´10² UFC/ml a >1,0´10(6) UFC/ml. Bactérias do grupo do Bacillus cereus foram verificadas em 13 (11,8%) amostras. Os resultados evidenciaram elevada população de microrganismos indicadores mesófilos.One hundred and ten ultra high temperature (UHT) milk samples, from 11 different brands retailed in São José do Rio Preto - SP were analysed for mesophilic heterotrophic microorganisms counting, as well as for the presence of Bacillus cereus. Mesophilic heterotrophic microorganisms ranged from ´10² CFU/ml to >1.0´10(6) CFU/ml. Bacillus cereus was detected in 13 (11.8%) samples. The results demonstrated high countings of mesophilic microorganisms.