Occurrence and level of Listeria monocytogenes and Salmonella in sushi at retails in Greater Jakarta area, Indonesia

Sushi is ready-to-eat food consisting of cooked vinegared rice and raw fish. Since sushi does not undergo heat treatment, inadequate control in the production may lead to microbial contamination. This study aimed to determine the prevalence and level of Listeria monocytogenes and Salmonella contamination in sushi sold in Greater Jakarta (Jakarta, Bogor, Depok, Tangerang, and Bekasi) area, Indonesia using the MPN-PCR method. Samples of sushi (n = 120), consisting of nigiri (rice with raw fish on top) (n = 57) and maki (rice with raw fish inside) (n = 63), were obtained from retail outlets in Jabodetabek. The results showed that both sushi products were more frequently contaminated with L. monocytogenes (14.2%) than Salmonella (2.5%). The contamination levels for L. monocytogenes and Salmonella were 3-1100 and 3.6-11 MPN/g, respectively. The highest prevalence of L. monocytogenes was found in maki sold in supermarkets (66.7%) and nigiri in kiosks (22.2%). In addition, maki and nigiri from restaurants have the highest prevalence of Salmonella at 2.2 and 3.8%, respectively. These findings indicate that contamination of L. monocytogenes and Salmonella in sushi sold at retail in Jabodetabek may pose a health risk to consumers and more study is needed to determine the source of contamination along the processing of sushi.