Occurrence of Methicillin-Resistant Staphylococcus spp. on Brazilian Dairy Farms that Produce Unpasteurized Cheese

Methicillin-resistant Staphylococcus spp. (MRS) have been identified in several foods, including dairy products. Studies are needed about their occurrence and genetic diversity in the dairy production chain in order to gain a better understanding of their epidemiology and control. This study therefore focuses on isolating and characterizing MRS strains detected in milk used in the production of Brazilian artisanal unpasteurized cheeses. To this end, samples were collected from bovine feces, the hands of milkmen, milking buckets, sieves, unpasteurized milk, whey, water, artisanal unpasteurized cheeses, cheese processing surfaces, cheese handlers, cheese trays, cheese molds, and skimmers at five dairy farms located in the state of São Paulo, Brazil. Colonies suggestive of Staphylococcus spp. were subjected to multiplex PCR to confirm the presence of Staphylococcus aureus and to detect the mecA gene. Sixteen isolates containing mecA gene were detected in samples from unpasteurized cheese and from cheese handlers. None of these isolates were positive to enterotoxin genes. These 16 isolates were subjected to antimicrobial susceptibility tests, which revealed they were resistant to oxacillin, penicillin, and cefepime. Using gene sequencing, the MRS isolates were identified as S. haemolyticus, S. hominis, and S. epidermidis. Furthermore, isolates from cheese handlers’ hands and artisanal unpasteurized cheese presented high genetic similarity by random amplified polymorphic DNA (RAPD-PCR) analysis, which indicates cross contamination during cheese production. Thus, we found that people directly involved in milking and cheese processing activities at small dairy farms are a potential source of contamination of MRS strains in unpasteurized milk and cheese, representing a risk to public health.

Bacteria from the Bacillus cereus group as contaminants in requeijão curd cheeses and especialidade láctea tipo requeijão

ABSTRACT: This study aimed to evaluate the occurrence of Bacillus cereus group in requeijões and especialidades lácteas tipo requeijão (regular and light) and to verify if there is differences in relation to this occurrence among different categories of these products. A set of 14 (35%) lots was contaminated with this bacterial group from the 40 lots with low counts (maximum 3.1 × 10 CFU/g), and no significant difference regarding counts or presence/absence were observed among the categories of the products. It can be concluded that contamination by B. cereus group in these products is unable to consist in risk to consumers, regarding adequate refrigeration during selling. This study was the first one to report this bacteria group for these dairy products and highlights the needs of further investigations to evaluate the impact of its spoilage during shelf life.

Effluents quality during the grow-out phase of the amazon shrimp macrobrachium amazonicum

In recent years shrimp culture farms have been one of the most growing sectors in aquaculture. Research has been carried out in order to establish a sustainable production maintaining profit and low environmental impact. Current investigation analyzed source and effluent water produced during the final grow-out phase of the Amazon shrimp (Macrobrachium amazonicum). Twelve natural-bottom ponds, with continuous water flow and stock density comprising 40, 60, 80 and 100 young shrimps/m² were analyzed. The experiment design comprised totally randomized blocks with four treatments and three replications. Microbiological analyses for Escherichia coli was attempted, coupled to physical and chemical analyses for pH, temperature, total suspended solids, total nitrogen, nitrite, nitrate, biochemical oxygen demand and chemical oxygen demand of water supply and pond effluents. Results show that whereas effluent quality complied with current legal rules, there was no significant difference between supply and effluent water for the analyzed variables and between stock densities. Under the conditions investigated and the intensification of culture in the final grow-out phase up to a density of 100 young shrimps/m², the production of M. amazonicum reveals low potential for environmental impact for the variables analyzed.

[Drinking water in rural farms as a risk factor to human health]

OBJECTIVE

To assess the sanitary quality of drinking water in rural farms through counts of microbiological indicators.

METHODS

A total of 180 drinking water samples from sources, reservoirs and water from site of consumption were collected in 30 rural farms located in the northeast region of the sate of São Paulo. The most probable number of total coliforms, Escherichia coli and mesophilic microorganisms were determined. Also, the presence of protection measures for water supplies wase verified.

RESULTS

The study results showed that 90.0% of drinking water samples from sources, 90.0% from reservoirs, and 96.7% from sites of consumption, collected during the rainy season, and 83.3%, 96.7% and 90.0% of samples collected in dry season were below the quality control standards for drinking water.

CONCLUSIONS

Drinking water in rural farms was considered a potential human health threat. Preventive measures for protecting water sources and water treatment are necessary to significantly reduce the occurrence of waterborne diseases.

Salmonella em carcaças de frango congeladas

Um total de 150 carcaças de frango congeladas, de quatro marcas comerciais, foram analisadas para pesquisa de Salmonella. Foram examinadas 43 carcaças de cada uma das marcas A, B, D e 21 da marca C. Observou-se um percentual de 32,0% de contaminação. Foram identificados 11 sorotipos: S. Agona, S. Anatum, S. Enteritidis, S. Hadar, S. Havana, S. Mbandaka, S. Montevideo, S. Ouakam, S. Poona, S. Schwarzengrund e S. I 4, 5, 12: -. O antibiograma das cepas mostrou 100% de resistência à ampicilina, 75,0% à cefalotina, 52,1% à cefoxitina, 22,9% à tobramicina, 6,2% à polimixina B e à tetraciclina, 4,2% à gentamicina e 2,1% à netilmicina, ao aztreonam e à amicacina. Todas as cepas apresentaram sensibilidade total ao cloranfenicol e ao sulfazotrim.