[Radiosensitivity of Vibrio cholerae O1 incorporated in oysters, to (60)CO]. / Estudo da radiosensibilidade ao 60Co do Vibrio cholerae O1 incorporado em ostras.

OBJECTIVE: Evaluate the effect of ionizing irradiation by 60Co on Vibrio cholerae O1, El-Tor, Ogawa, non-toxigenic, incorporated in live oysters Crassostrea brasiliana. METHODS: Samples of oysters were selected from Cananéia town in the South coast of S. Paulo state, Brazil, contaminated with Vibrio cholerae and irradiated with 60Co at 0.5 and 1.0 kGy dosages. RESULTS: Showed significant reductions of the initial number of V. cholerae, ranging from 3.4 x10(7) to 10(3) and 10(2), respectively. The D10 values related with the respective doses of irradiation were 0.173 and 0.235. CONCLUSION: Considering a 6 value as safety factor, it is concluded that 1.41 kGy irradiation dosage is necessary to eliminate a high number of V. cholerae viable cells in oysters. Controls were used in the experiment.

Estudo da sensibilidade in vitro de diferentes cepas de vibrio cholerae 01 à raiaçäo gama de 60Co / Study about the sensibility in vitro of different strains of vibrio cholerae 01 exposed to 60 Co gamma radiation

A presença de certos microrganismos nos alimentos ou de metabolitos originados durante sua multiplicaçäo pode dar lugar a várias enfermidades no homem: as intoxicaçöes e as infecçöes alimentares. Dentre os agentes causadores das Enfermidades Transmitidas por Alimentos encontra-se o Vibrio cholerae 01. Estudou-se no presente trabalho a radiossensibilidade in vitro de quatro cepas de V cholerae 01, submetidas ao tratamento com diferentes doses de radiaçäo ionizante de 60 sobrescrito Co, e compararam-se os resultados obtidos com dados da literatura relacionados a problemas de veiculaçäo alimentar de bactérias patogênicas, incluindo a água

Use of probes to detect virulence factor DNA sequences in Escherichia coli strains isolated from foods.

Escherichia coli strains were isolated from 96 food samples (32 milks, 4 dairy products, 36 raw meats, 7 meat products, 7 sandwiches and 10 ready-to-eat meals). A total of 306 colonies was submitted to hybridization assays with DNA probes for the following virulence factors: heat-labile toxins (LT-I and LT-II), heat-stable toxins (ST-h and ST-p). Shiga-like toxins (SLT-I and SLT-II), adherence factor of enteropathogenic E. coli (EAF) and invasive factor (INV). Six colonies isolated from 4 food samples hybridized with the probes for LT-II (3 colonies isolated from a milk sample), SLT-I and SLT-II (1 colony isolated from raw bovine meat) or EAF (2 colonies isolated from two raw chicken meat samples).