Campylobacter screener speeds-up test results

Tougher regulatory standards and the increased reporting of food contamination in restaurants, supermarkets and processing plants has pushed companies to put a higher priority on safety, shelf life and cleanliness.

However, stringent testing cause delays in products hitting the shelves and so processors are constantly searching for faster methods to test food safety.

DuPont Qualicon BAX's new real-time campylobacter assay can produce results within two and a half hours for contaminated samples, and within two days for those requiring enrichment, the manufacturer claims.

Most current screening procedures for campylobacter are culture-based, take at least three days for a result and do not differentiate between species without additional investigational work, the company said.

The new assay also allows differentiation between the pathogenic species C. jejuni, C. coli and C. lari, and quantification of three campylobacter species.

Campylobacter infection is a worldwide public health concern and is the leading cause of enteric illness in many countries.

With about 50,000 human cases of illness per year, campylobacter is the most common known cause of foodborne infection contracted in UK.

Campylobacter species differ from other food pathogens in that they do not multiply within the food. However, as few as 500 cells are sufficient to cause infection. The organism is endemic in many poultry populations and whilst normally responsible for self-limiting enteritis, infection can lead to severe complications such as arthritis and Guillain-Barré syndrome, which is an acute paralytic disease of the nervous system.

C. jejuni is responsible for approximately 90 per cent of these infections, although C. coli and C. lari have also been implicated. The commercial cost of the disease associated with poultry alone has been estimated at between €270m ($350m) and €550m ($712m) annually.

Polymerase chain reaction (PCR) is a method used for amplifying and detecting specific DNA in a sample. The BAX real time campylobacter assay uses PCR and probe-based chemistry to detect, quantify and differentiate between the three species of campylobacter in the same sample.

DuPont Qualicon BAX system targets specific probes by measuring fluorescence. The BAX system is simple and testing is straight-forward and requires no additional equipment, the manufacturer claims.

All reagents required for PCR are supplied in a single tablet packaged inside the PCR tubes provided in each kit.

Tableted reagents minimise the amount of hands-on time required for processing whilst simultaneously simplifying and standardising the procedure, claims the company.

Results are interpreted automatically and are ready for reporting. If necessary, icons and graphs make further result queries simple and easy to visualise, the company said.

The Food Standards Agency strategic plan for 2005 - 2010 includes a commitment "to work with the industry to achieve a 50 per cent reduction in the incidence of UK produced chickens which test positive for campylobacter by 2010"​.