Microbiological and Physicochemical Qualities of Sushi and Sashimi from Japanese Restaurants in Brazil

Abstract

Japanese cuisine is known for its nutritional and sensory quality. Sushi and sashimi are highly perishable and widely consumed foods in Brazil. The production and storage of these foods under appropriate conditions are critical factors in ensuring consumer safety. This study was carried out to evaluate the microbiological and physicochemical conditions of sushi and sashimi sold in Japanese restaurants as well as their handling conditions. Samples of sushi (36) and sashimi (35) and 112 swabs of food handlers were collected from 18 Japanese restaurants of the central region, Brazil. Temperature, pH and Total Volatile Nitrogen Bases (in sashimi) of food samples were determined. Thermotolerant coliforms, coagulase positive Staphylococcus, Vibrio parahaemolyticus, Bacillus cereus (in sushi) counts and the detection of Salmonella sp. were also performed. Staphylococcus aureus and Escherichia coli were investigated in the swabs samples. The average temperature of the food samples at all the restaurants was higher than the recommended value as well as 63.9% of the sushi and 54.3% of the sashimi samples had above recommended pH. All sashimi samples had content within legal limits of Total Volatile Nitrogen Bases. Four samples (5.6%) were positive for thermotolerant coliforms, and in three of them (4.2%), E. coli was isolated. High counts of Bacillus cereus were found in 22.2% of the sushi samples. Coagulase positive Staphylococcus, Vibrio parahaemolyticus, and Salmonella sp. were not found in the samples analysed. In 9.0% of the clinical samples, thermotolerant coliforms were detected and E. coli was found in 5.4% (n = 6) of them. Staphylococcus aureus was not detected on any food handler. The high storage temperature of food, the lack of heat treatment and the microbial contamination found may lead the present microorganisms to reach high counts until consumption, and therefore represent risk to consumers. Thus, effective prevention by supervisory bodies is essential.