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1.
J Dairy Sci ; 99(11): 8589-8597, 2016 Nov.
Article in English | MEDLINE | ID: mdl-27544854

ABSTRACT

The objectives of this study were to characterize Staphylococcus aureus isolated from artisanal and industrialized Minas frescal cheeses, to determine their antimicrobial susceptibility profile as well as the genetic similarity among the isolates. The isolates were also tested for staphylococcal enterotoxin genes and other virulence factors. Fifty-six artisanal raw milk cheeses sold at street fairs and 10 industrialized cheeses commercialized in supermarkets of Goiânia, Goiás, were analyzed. Staphylococcus aureus was confirmed in 19 samples (33.9%) of artisanal cheese by detection of femA gene, in which 29 isolates were obtained. These isolates were submitted to the antimicrobial susceptibility test and classified into 9 different profiles (A-I). Thirteen isolates (44.8) were resistant to penicillin and 3 (10.3) to tetracycline, with 2 (7.4) resistant to both. The multiplex PCR technique was performed to detect virulence genes that code for the production of hemolysins (Hla and Hlb), toxic shock syndrome toxin (TSST-1), exfoliative toxins (ETa and ETb), and staphylococcal enterotoxins [SE; SEA-SEE, SEG-SEJ, SEM-SEO]. All the isolates amplified for the hla gene and 14 (48.3%) for the hlb gene. The seh gene was the most frequently detected (n=11, 37.9%), followed by seo gene (n=3; 10.3%). In one isolate (3.4%), 4 enterotoxins genes were detected, and in another, 6 (3.4%) were detected. The comparison performed by pulsed-field gel electrophoresis of the 29 isolates revealed 18 genotypic profiles, which were grouped into 5 clusters. The genotyping found high genetic similarity among the isolates. Identical isolates were obtained from different samples and one sample showed more than one genetically different isolate. The high prevalence of S. aureus in the Minas Frescal cheese samples, as well as the detection of toxin encoding genes identified in this study, warns of the necessity to reduce the contamination levels in this type of cheese through monitoring and controlling the production and trade of the product.


Subject(s)
Cheese , Staphylococcus aureus , Animals , Enterotoxins/genetics , Food Contamination , Food Microbiology , Genotype , Milk/chemistry , Polymerase Chain Reaction , Staphylococcus aureus/genetics , Staphylococcus aureus/growth & development , Staphylococcus aureus/pathogenicity , Virulence
2.
Arq. bras. med. vet. zootec ; 61(5): 1203-1209, out. 2009. tab, ilus
Article in English | LILACS | ID: lil-532034

ABSTRACT

From February 2004 to March 2005, 140 samples of food handlers - hands and nostrils - (92), raw milk (24), and minas frescal cheese (24) were analyzed for the presence of Escherichia coli in a dairy processing plant of Goiás State. Forty-seven E. coli strains were obtained and compared by DNA macrorestriction patterns obtained from pulsed-field gel electrophoresis following XbaI restriction in order to investigate the possible sources of cheese contaminations. Based on PFGE genotyping, one strain isolated from food the hands of a handler and five strains isolated from raw milk were identical or closely related to six strains from cheese suggesting, in these cases, the probable source of E. coli contamination in cheeses. No strain isolated from the nostrils was related to those found in cheeses or milk strains. The results showed high diversity among the strains, demonstrating a lack of predominance of an endemic clone in the dairy plant. This paper highlights the usefulness of PFGE as an epidemiological tool for determining the source of E. coli contamination in the food industry.


Durante um ano, de fevereiro de 2004 a março de 2005, 140 amostras retiradas das mãos e das narinas de manipuladores de alimentos (92), do leite cru (24) e do queijo-de-minas frescal (24) foram analisadas para a presença de Escherichia coli, em um laticínio do Estado de Goiás. As 47 cepas obtidas foram comparadas por macrorrestrição do DNA com enzima XbaI, seguida de eletroforese em gel em campo pulsado (PFGE), a fim de investigar as possíveis fontes de contaminação do queijo. Baseado na genotipagem pelo PFGE, uma cepa obtida do leite cru e cinco cepas obtidas dos manipuladores mostraram similaridade maior que 80 por cento com seis cepas isoladas do queijo, denotando forte correlação genética entre elas e sugerindo, nestes casos, a fonte provável de contaminação do produto final. Nenhuma cepa isolada do nariz foi relacionada às isoladas do queijo ou do leite. Os resultados mostraram grande diversidade entre as cepas, demonstrando ausência de um clone endêmico no laticínio avaliado. Este estudo destaca a utilidade do PFGE como uma ferramenta importante em investigações epidemiológicas e na determinação de possíveis fontes de contaminação por E. coli na indústria de alimentos.


Subject(s)
Escherichia coli/isolation & purification , Milk/microbiology , Cheese/microbiology , Electrophoresis, Gel, Pulsed-Field/methods
3.
Hig. aliment ; 16(102/103): 63-70, nov.-dez. 2002. tab
Article in Portuguese | LILACS | ID: lil-340429

ABSTRACT

Teve como finalidade avaliar as condições microbiológicas e mensurar o pH e a temperatura de saladas de vegetais com maionese fornecidas em 58 restaurantes comerciais tipo self-service localizados na região central de Goiânia. Os resultados foram bastante heterogêneos, com grande variação nas contagens, principalmente para os coliformes totais, bem como números elevados nas contagens de mesófilos e bolores e leveduras. Nenhuma amostra revelou-se positiva para Salmonella. O pH variou de 4,24 a 6,3, situando-se acima do pH exigido pelas recomendações federais/EUA, para garantir a segurança microbiológica da maionese preparada com ovos não pasteurizados. Todas as amostras apresentaram temperatura acima de 10ºC, sendo consideradas em desacordo com as recomendações estabelecidas pelo Codex Alimentarius e pela ABERC para a manutenção de pratos frios prontos para o consumo. Os resultados obtidos nas contagens dos microrganismos podem ser considerados elevados, indicando, provavelmente, que sejam decorrentes de práticas inadequadas de manipulação e/ou armazenamento.


Subject(s)
Food Microbiology , Food Quality , Restaurants
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