Specific chromogenic assay for detection of hippuricase-positive bacteria and its validation in raw chicken meat samples

Campylobacter infections are behind most pathogenic food contamination cases in humans. Campylobacter jejuni is a pathogen commonly found in the food chain and especially in meat products. Contamination takes place already during the slaughtering process and affects the whole supply chain until the consumer. Campylobacter contamination is still hard to prevent, and this work reports a specific easy-to-read biochemical assay for live Campylobacter with a rapid visual detection from a small bacterial sample. Current PCR- and ninhydrin-based detection assay both present significant limitations in sustainability, applicability, and reliability. This work presents a biochemical easy-to-read assay for live Campylobacter proceeding in two steps and requiring water-based solutions for an improved safety and sustainability; moreover, it has been validated with chicken meat samples using mass-spectrometry techniques. The assay efficiently allows the discrimination of a microorganism having hippuricase activity, e.g. C. jejuni, from microorganisms without hippuricase activity as it delivers a bright pink color in positive samples.