Use of blood-free enrichment broth in the development of a rapid protocol to detect Campylobacter in twenty-five grams of chicken meat

A Food Pathogen Enrichment (FPE) broth, which supports the growth of Campylobacter without lysed blood and CO2, was developed. The FPE broth supports the growth of Campylobacter to the same degree as Bolton and Preston broths. Using the FPE broth, we developed a novel rapid protocol to detect small numbers of Campylobacter in 25 g of food. The sensitivity of FPE enrichment and PCR to detect Campylobacter spp. from spiked chicken meat was determined. The detection sensitivities for non-stressed C. jejuni and C. coli from fresh meat ranged from 5.8 to 1.1 × 101 CFU per 25 g of chicken meat, and those for freeze-stressed C. jejuni and C. coli from frozen meat ranged from 9.9 × 101 to 2.0 × 102 CFU. The FPE broth enrichment culture (24 h) of chicken meat, followed by PCR, resulted in a significantly higher detection score (80% positive) than conventional Bolton enrichment and subsequent colony isolation using mCCDA agar plates (18% positive). Differences between our new protocol and the Bolton enrichment method were due to the overgrowth of many resistant bacteria, especially extended-spectrum beta-lactamase-producing bacteria in the Bolton enrichment broth.

► FPE broth supports the growth of Campylobacter without lysed blood or CO2.
► Our protocol detected 5.8 to 1.1 × 101 CFU of Campylobacter in 25 g of chicken.
► FPE-based PCR detection was superior to Bolton-based isolation.
► 80% of chickens were C. jejuni-positive by the FPE method; only 18% were by the Bolton method.
► FPE broth successfully suppressed the growth of contaminating bacteria.