Imaging technique cuts Campylobacter detection time

The Agricultural Research Service (ARS) said its innovative hyperspectral imaging can identify the foodborne pathogen in around 24 hours as compared to current method that can take up to a week. The technology combines digital imaging with spectroscopy, to provide hundreds of individual wavelength measurements for each image pixel.

Fingerprint​

According to the ARS researchers, microorganisms that are grown on solid media “carry unique spectral fingerprints in the specific portion of the electromagnetic spectrum”.​

The scientists said their hyperspectral imager identifies these fingerprints by measuring light waves that bounce off or through these objects. The technique can detect light from the ultraviolet to near-infrared ranges as well as normal visible light.

The groups said hyperspectral imaging may also be applicable to other pathogen detection techniques and they are also working toward developing a presumptive screening technique to detect Salmonella and Campylobacter in food samples.

Major source of foodborne illness​

Campylobacter has been identified by both the US Department of Agriculture and the European Food Safety Authority (EFSA) as a major source of foodborne outbreaks. A recent survey by the European food safety watchdog found around 80 per cent of poultry carcasses in the region were contaminated with Campylobacter and the UK Food Standards agency has highlighted the bug as its number one food safety concern.

The ARS, which is the research arm of the USDA, said growing Campylobacter directly on solid media was an effective method to isolate the organism, but that distinguishing it from other bacteria had been difficult because different microorganisms can look similar.

Lead by electronics engineer Seung-Chul Yoon, the team developed the imaging technique to detect Campylobacter colonies on solid media in 24 hours.

“Normally, isolation and detection for identification of Campylobacter from foods like raw chicken involve time-consuming or complicated laboratory tests that may take several days to a week,”​ said a statement from the group.

They claimed the ‘sensing’ technology was almost 100 per cent accurate with pure cultures of the microorganisms. It could be used for early detection of presumptive Campylobacter colonies in mixed cultures, they added. The researchers are working toward developing a presumptive screening technique to detect Salmonella and Campylobacter in food samples.