Abstract
For the surveillance of the prevalence of Campylobacter jejuni and Campylobacter coli in raw chicken products in Japan, a qualitative method, National Institute of Health Sciences Japan (NIHSJ)-02, was developed as an alternative to International Organization for Standardization (ISO) 10272-1:2006. In the NIHSJ-02 culture method, the enrichment step is carried out in a reduced volume of Preston broth at 42 ± 1°C to reduce cost and space, and to prevent the overgrowth of background bacteria. To evaluate the performance of NIHSJ-02, a collaborative study was conducted, and the results obtained by NIHSJ-02 were compared with those obtained using the reference method, ISO 10272-1:2006. Fifteen laboratories participated; each examined 48 minced chicken samples consisting of test samples uninoculated, inoculated with C. jejuni at a low or high level, and inoculated with C. coli at a low level. The average probabilities of detection by NIHSJ-02 across laboratories were 0.033, 0.222, 0.678, and 0.267 in samples uninoculated, inoculated with C. jejuni at a low and high level, and with C. coli at a low level, respectively. Those by ISO 10272-1:2006 were 0.051, 0.128, 0.551, and 0.090. Significantly higher probabilities of detection were determined by NIHSJ-02 compared to ISO 10272-1:2006, except for uninoculated samples. On the other hand, significantly lower frequency of occurrence of background bacteria was observed by NIHSJ-02 (43.1%) compared with ISO 10272-1:2006 (92.6%). NIHSJ-02 showed better performance than ISO 10272-1:2006 with regard to the selective detection of C. jejuni and C. coli in chicken.