Campylobacter - a growing threat to food safety

A recent report by the EFSA [1] showed that Campylobacter continues to be the largest source of zoonoses in the European Union (EU). In 2007, there were 200,507 reported cases, reflecting a 14% increase over 2006. About 45 in every 100,000 EU residents were affected by Campylobacteriosis in 2007, mostly due to eating contaminated poultry meat.

Campylobacter is found in 26% of fresh poultry meat, along with live poultry, pigs and cattle. Reducing the risk of contamination, particularly in poultry, requires active screening and interventions all along the farm-to-fork continuum. This article will provide an overview of Campylobacter in food and animals, along with information on a genetic-based system that detects Campylobacter in food as effectively as traditional culture methods, but with quicker time to result.

What is campylobacteriosis?
Campylobacteriosis is an infectious disease caused by Campylobacter bacteria. It is characterized as a zoonose, which means that it is transmitted from animals to humans, either through direct contact or from consumption of contaminated food products. The most frequent species associated with human illness is C. jejuni (44%), but C. coli (3%) and C. lari (0.3%) are also known to cause infection.

Campylobacter contaminate the alimentary tracts of wild and domesticated birds, along with pigs, cattle and other animals. According to the U.S. Centers for Disease Control [2], C. jejuni grow best at the body temperature of a bird, which can carry it without becoming ill. The bacteria are fragile and cannot tolerate drying. They can be killed by oxygen, and freezing reduces the number of cells on raw meat.

Most cases of campylobacteriosis are associated with eating contaminated meat, raw milk and dairy products, although fish, mussels and fresh vegetables can also cause it. Symptoms typically include watery diarrhea, abdominal pains, fever, headache and nausea. Infected people usually recover in a few days, but complications can include reactive arthritis and neurological disorders. C. jejuni is recognized as an antecedent cause in many cases of Guillain- Barré syndrome, a paralysis that can lead to a damage of respiratory and neurological functions and even death.

The EFSA reported a 14% increase in confirmed cases of campylobacteriosis in 2007. Although most member states reported higher numbers, Germany accounted for 56% of the increase. Incidence rates varied by age group with children under the age of 5 highly sensitive to campylobacteriosis (120 cases per 100,000 population), while the proportion for other age groups varies between 32 and 53 cases per 100,000.

Prevalence of Campylobacter
According to the EFSA report, Campylobacter was found in about 26% of broiler flocks, although this rate varied widely (0 to 86%) among Member States and was lower in some Nordic countries. None of the reporting countries has seen a decrease in Campylobacter infections in recent years.

In 2007, the level of Campylobacter detected in fresh poultry meat was generally high (26%) but varied widely, with Estonia, Latvia, and Romania reporting lower rates. A closer examination shows that 46 % of the Campylobacter isolated from fresh broiler meat were C. jejuni, 18% were C. coli, 0.6% were C. lari, and 0.1% were C. upsaliensis, along with a large proportion of unspecified Campylobacter isolates.

Pig and bovine meat is less frequently contaminated by Campylobacter. Although 56% of pigs in the EU tested positive in 2007, less than 1.1% of retail fresh pig meat was contaminated. About 6% of cattle were reported positive in the EU-with higher rates in Austria, Denmark and Spain-but Italy was the only country that showed bovine contamination at the retail level (2.4%).

C. jejuni is the species found most often in cattle (87%), while pigs are most frequently contaminated by C. coli (87.1%).

Campylobacter in raw cow's milk was very low (<1%) in 2007, although Germany and Hungary showed a higher frequency of occurrences. That same year, Campylobacter was not found in any of the 234 seafood and fishery products tested. Goats, sheep and pets have also showed some contamination by Campylobacter but not in equally high levels.

Implications
The data collected in the ESFA report helps to identify the most frequent sources of Campylobacter in animals and food. The biggest source appears to be poultry, where high rates found in live broilers decreases only slightly in processed meat found at retail.

As a logical consequence, the preliminary opinion of the EFSA Scientific Panel on Biological Hazards related to Campylobacter is that the major source of risk is posed by poultry meat products. The most frequent cause of human campylobacteriosis appears to be cross-contaminated ready-to-eat food and direct hands-to-mouth transfer during food preparation. The consumption of undercooked poultry meat is also a cause of infection but to a lesser extent.

Other sources of risk are bivalve molluscs, contaminated drinking water, raw milk and meat from pigs and ruminants especially by consuming undercooked offal.

In 2008, the EFSA Panel on Biological Hazards created a working group charged with verifying the extent to which meat derived from broilers contributes to campylobacteriosis in humans in the EU. Next, each production stage will be examined to identify and rank the possible control options. At different stages of the broiler meat production chain, the working group will propose potential reduction targets for Campylobacter.

Two more EFSA reports on Campylobacter in broilers are expected in 2009. The first report addresses prevalence estimates and the second report focuses on risk factors. With that information, the EFSA Panel on Biological Hazards will have enough data to assist the European Commission (EC) in setting reduction targets for Campylobacter.

Detection is the first step
Food processors/manufacturers play a crucial role in food safety between the farm and the fork, serving as a critical gatekeeper. Beyond reduction targets that will be set by the EC for farm animals, vigilance in detecting the presence of campylobacter in raw ingredients, finished products and the processing/manufacturing environment is critical so that food companies can protect their products and their brand.

One concern often voiced by food processors/manufacturers is the long delay in getting results from a traditional culture-based testing method. Waiting up to four days to make release decisions can mean the difference between profit and loss, especially with today's growing demand for products with fewer preservatives.

Fortunately, food processors/manufacturers now have alternatives. For example, the BAX® detection system from DuPont Qualicon provides the food industry with a real-time genetics-based method for detecting three species of Campylobacter (C. jejuni, C. coli and C. lari) simultaneously and independently. The assay delivers quantitative same-day results for highly contaminated samples or qualitative next-day results for enriched samples. The use of automated polymerase chain reaction (PCR) processing with tableted rather than liquid reagents creates a dramatic increase in speed and decrease in variability.

Extensively validated, the BAX® system is used around the world for food safety and quality testing. Its Campylobacter PCR assay has been certified by AOAC and approved for use by several government agencies, including Russia and China.

If Campylobacter is detected in a food processing plant, intervention strategies to reduce or eliminate the bacteria should be incorporated into a good HACCP plan. According to a report from the Denmark National Food Institute [3], good hygiene practices (biosecurity), including fly control, are key to preventing flock contamination, while probiotics and other feed/water additives are aimed at infected flocks. The Danish action plan for 2008-2012 to control Campylobacter in broilers recommends post-slaughter physical interventions such as steam-ultrasound treatments and but freezing to significantly reduce the number of Campylobacter on broiler meat.

Conclusion
As described above, C. jejuni, C. coli and C. lari are the species that account for the vast majority of human campylobacteriosis. It's not unreasonable to expect that they will most likely be targeted for reduction by the European Commission (EC). Because it is a ubiquitous organism, this will surely be a challenge for the Member States, especially those with high contamination levels. Key to maintaining profitability will be effective strategies for prevention, detection and remediation.

References:
[1] European Food Safety Authority (EFSA) report: "The community summary report on trends and sources of zoonoses and zoonotic agents in the European Union in 2007"
[2] U.S. Centers for Disease Control, Division of Foodborne, Bacterial and Mycotic Diseases (DFBMD), http://www.cdc.gov/nczved/dfbmd/disease_listing/campylobacter_gi.html
(accessed March 30, 2009)
[3] Rosenquist, H., L. Boysen, and B. Borck (ed.). 2008. "Interventions to control Campylobacter in the broiler production. Report of an International Expert Consultation, Copenhagen, Denmark, 26-27 November 2007." National Food Institute, Technical University of Denmark, Copenhagen. http://www.food.dtu.dk/Admin/Public/DWSDownload.aspx?File=Files%2FFiler%2FZoonosecentret%2FPublikationer%2FInterventions_to_control_Campylobacter_in_the_broiler_production.pdf. (accessed March 30, 2009)

Contact details:
Alain Minelli
Qualicon EMEA Marketing
T: +41 (0)22 717 5913
E: alain.minelli@che.dupont.com
www.Qualicon.com