Abstract
In Japan, foodborne illness caused by Salmonella have decreased year by year recently, but Salmonella is an important causative agent of potential risks associated with death. However, the standard method applying food hygiene is not fully established at present. Then, we evaluate the advanced method for detecting Salmonella from foods which was improved the official method for pasteurized liquid egg established on Nov. 1998. Sensitivity of the method was tested by two kinds of Salmonella strain (H2S producing and non-H2S producing strain). Both kinds of Salmonella strains inoculated in foods (3 or 7 cfu/25 g sample) were clearly detected by the advanced method. Moreover, practical use for detection of Salmonella in ground chicken meat and unpasteurized whole liquid egg was tested. Retailed ground chicken meat was naturally contaminated by Salmonella at a ratio of 40/70 at Tokyo and Osaka. However, concentration of Salmonella was not so high. Mean of MPN (most probable number)/g was under 0.33/g. On the other hand, unpasteurized whole liquid egg was naturally contaminated by Salmonella. It was shown higher MPN number than that of ground chicken meat. Ground chicken meat was mainly contaminated by S. Infantis and non-sterilized liquid whole egg was mainly contaminated by S. Enteritidis. Food causative agent of Salmonella is mainly S. Enteritidis in Japan. Egg contamination of Salmonella needs to be monitored now and in the future. PCR and LAMP detection after BPW enrichment was fully effective for Salmonella in non-sterilized liquid whole egg but that was less effective for Salmonella in chicken ground meat. The new advanced detection methods for Salmonella in food are useful and sufficient for detecting few Salmonella in food.
