Abstract
Outbreaks of shigellosis have been associated with traveling to areas with poor hygiene. However, the number of foodborne cases is increasing in industrialized countries. Since the infectious dose of Shigella spp. is as low as 10 cells, a rapid and sensitive method of detecting Shigella spp. in food is required. The Ministry of Health, Labour and Welfare of Japan (MHLW) released a detection protocol for Shigella spp. from oysters in 2002, but a number of problems with it, including low sensitivity and instability of results, have been identified. In this study, a new detection method was established based on the MHLW protocol with some modifications. We introduced mechanical stomaching instead of manual squeezing in the sample preparation step, a zirconia beads breakage procedure for DNA extraction in place of boiling, and real-time PCR instead of multiplex PCR. The results indicated that the new method had ten times the sensitivity of the MHLW protocol. Hence, we propose this sensitive and rapid real-time PCR based method to contribute to the improvement of Shigella spp. detection in food and assure food safety.
