Purpose: The purposes of this study were to develop enrichment broth (Bolton broth with 12.5 mg/l rifampicin, R-Bolton broth) and to determine a newly designed R-Bolton broth-subsequent selective media combination for C. jejuni/coli detection in vegetables and poultry.
Methods: In order to evaluate survivability of C. jejuni/coli according to concentration of rifampicin, C. jejuni/coli were inoculated and incubated in Bolton broth with each concentration, 0 mg/l, 10.0 mg/l and 12.5 mg/l, of rifampicin at 42°C for 48 h microaerobically. For the determination of a selective agar, 125 of Campylobacter spp. and other bacteria were incubated in R-Bolton broth, followed by streaking onto several selective agars, respectively. Finally the combination of R-Bolton broth and CampyFood Agar (CFA) was applied to chicken and 3 kinds of vegetables for validating its performance.
Results: First of all, no significant differences in C. jejuni/coli growth were found among enrichment media with various levels of rifampicin. In addition, the combination of R-Bolton broth and CFA showed the highest specificity (99.2 %). When applied to food samples, such as, romaine lettuce, chicken, tomato and Korean leek, the combination decreased false-positive results by 58.3%, 55%, 16.7% and 8.3% for respectively, compared to a standard method.
Significance: It was demonstrated that combination of newly developed R-Bolton broth and CFA is useful to detect C. jejuni/coli in food with suppressing non-Campylobacter bacteria.