Using peptide nucleic acid fluorescence in situ hybridization (PNA-FISH) to detect Campylobacter spp. in food samples

Foodborne diseases have a considerable negative impact on socioeconomic development globally and are an important cause of morbidity and mortality. Among the foodborne bacterial pathogens, Campylobacter spp. is recognized as the leading cause of foodborne illness. Fluorescent in situ hybridization using nucleic acid mimics (NAM-FISH) as probes, in particular peptide nucleic acid (PNA) probes, is a molecular technique that has emerged as an essential and resourceful tool for bacterial detection. Here, we applied a PNA-FISH methodology, including pre-enrichment culture, for the specific detection of Campylobacter spp. in food matrices, more specifically fresh raw broiler meat and fresh raw pork. New PNA probes, including a blocker probe, have been designed for a 23S rRNA sequence. The PNA-FISH technique presented sensitivity and specificity values of 92.0% and 96.9%, respectively. In food matrcies, the best detection condition was achieved with a pre-enrichment of 48 h in Bolton broth, allowing a detection limit of 1 CFU/25 g. Compared to the ISO 10272-1:2017 reference method, this methodology showed similar performance in food matrices. The present study revealed that the developed PNA-FISH method is a promising alternative for detecting Campylobacter spp. in food samples.