4 ways to cut campylobacter in UK poultry

Reducing campylobacter levels on poultry farms is an achievable objective if the right policies are adopted. Philip Clarke summarises the key findings of the latest Nuffield scholarship report.

The Food Standards Agency should change its approach to reducing campylobacter and, instead of naming and shaming supermarkets, should introduce mandatory monitoring and testing for the whole supply chain.

That is one of the primary recommendations from Hook 2 Sisters’ general broiler manager Werner Strydom (pictured), in his recently published Nuffield scholarship report on reducing campylobacter.

Mr Strydom visited six countries in the course of his studies: New Zealand, Norway, Denmark, Sweden, the US and Iceland – all carefully selected because of the success they have had in countering the bug.

See also: Nuffield report – Poultry has the power to feed the world

“All the countries I visited have a mandatory campylobacter monitoring programme. All are successful and have been shown to reduce the number of people getting poisoning from campylobacter.”

For example, in Norway, faecal samples are taken three days prior to slaughter, and carcasses from all flocks testing positive must be heat-treated or frozen. Campylobacter positive flocks are also processed in the factory at the end of the day, to prevent cross-contamination.

A similar policy was adopted in Iceland in 2000, leading to a 75% drop in the number of human cases of campylobacter poisoning within a year.

Denmark, in contrast, majors on testing caeca and thigh skin samples in the factory. This has led to the creation of an extensive database, which has helped the industry identify farms and factory processes which are contributing to the problem.

Four keys to conquering campylobacter

  • Mandatory testing and monitoring
  • Phase out thinning of broiler flocks
  • Improve biosecurity
  • Reduce age of slaughter

Mr Strydom says these sorts of monitoring systems are far better than the “name and shame” strategy adopted by the FSA in the UK.

He concedes that the policy of testing supermarket chicken every quarter and publishing the results has been successful in putting pressure on the supply chain to raise standards.

“My reservation is that the FSA has turned an industry problem into a retailer problem,” he says in the report. “Retailers are starting to move orders between suppliers to try to capture good publicity when the quarterly results are published. I do not believe this is an effective strategy.

“During my travels I discussed the FSA strategy with most of the people I visited and none of them thought it was the correct approach for the UK to take.” One New Zealander said it “smacks of desperation due to a failed strategy”.

Introducing a mandatory programme in the UK would force all producers to test their flocks, enabling the whole supply chain to focus on making improvements. “Campylobacter is an industry problem and the whole industry needs to work together to provide consumers with a safer product.”

Thinning – pros and cons

Phasing out thinning is another key recommendation in Mr Strydom’s report, in order to minimise the chances of biosecurity breakdown.

The report notes that most birds that are left behind after thinning contract campylobacter within two or three days.

“There is still some debate as to whether the bacteria was introduced into the house on the people and equipment, or if the stress of thinning causes some birds to shed the bacteria in high numbers,” he says. “I believe that catching equipment is the source of the bacteria. It is cleaned, but not sterilised and therefore the bacteria are constantly being circulated between the processing plant and the different farms.”

Different countries have different approaches, the report notes. The Scandinavian countries do not thin due to the risk of infecting remaining birds. New Zealand, in contrast, thins three times and relies on antimicrobial treatments in the plant to quash campylobacter.

Iceland stopped thinning a few years ago, and the number of campy-positive flocks fell from 40% to 15%.

In the UK, trials are continuing into the impact of no thinning, though Mr Strydom says there is a reluctance to go down this route due to the impact on the cost of production. Just thinning once enables output per flock to rise from 38kg/sq m to 47kg/sq m, which spread over 7.4 crops a year, is equivalent to an extra 67.5kg/sq m a year.

Banning thinning would certainly push up the cost and make the UK poultry market more vulnerable to imports. “Without government intervention, the UK will have to rely on the retailers’ commitment to selling UK chicken in their stores,” says Mr Strydom.

The report does, however, suggest that no thinning policies may be adopted more widely, pointing to the success so far of a year-long trial by 2 Sisters Food Group. At the half-way point of the trial it was shown that non-thinned farms had about half the number of campylobacter-positive flocks as the control farms, while the cost was put at 5p/kg.

“If the trial is successful, the no-thinning results could show that the levels in processing plants can be kept below the FSA target and there will be a good case to have no-thinning adopted more widely.”

Mr Strydom also maintains there is a strong welfare argument for stopping thinning, with remaining birds subjected to the same feed withdrawal period as the birds that are being taken, as well as the noise and stress of having catching teams in the sheds.

“In my view, due to the cost involved, the UK industry, retailers and the FSA are in denial about the effect no thinning will have on the number of positive flocks each year.”

Thinning – five mitigating factors

Should legislation be passed to ban thinning, five factors will help offset the impact

  • Growth rates will increase – as currently, remaining birds stall for two or three days once the catchers have been in
  • Slaughter age will reduce – as birds reach target weight sooner, meaning more birds per year
  • Lower mortality – as stress is reduced, meaning more birds per flock reach slaughter
  • Stocking density should be reviewed – to take the current 38kg/sq m limit to 42kg/sq m, as allowed under EU legislation
  • Broiler genetics are improving – leading to faster growth rates

Biosecurity and age of slaughter 

The UK industry has made huge strides in improving biosecurity on farms over the past decade, prompted by concerns about campylobacter as well as avian influenza. “But we still have a long way to go to get the UK poultry industry to the level of Scandinavian broiler farms,” says Mr Strydom.


Double barriers are standard practice in Norway

Producers in Iceland are encouraged to think of their broiler sheds as operating theatres, while in Norway, double barriers are standard practice on all farms. This means each control room is fitted with two barriers, dividing the room into dirty, semi-clean and clean areas, each with its own separate drainage system and other protocols.

Shed-specific boots are all washed, disinfected and stored upside down to ensure no campylobacter survives. Every clean area also has a shed-specific toolbox, so there is no need to move tools between houses.

And in Sweden, the buildings are often designed so that the door into the birds is at right angles to the door in from the yard, to encourage people to slow down and go through all the right procedures.

In Iceland, some processors have a “no wood” policy in poultry sheds, as wooden posts can’t be cleaned as effectively as metal structures. Shaving bales are placed in houses at turnaround before disinfectant is applied, and turned half way through the process to ensure both sides get sprayed.


Swedish producers net off air vents to prevent campy-carrying birds and insects from entering their sheds

Scandinavian producers are also convinced that flies and wild birds are vectors for campylobacter, so have worked hard to exclude them from broiler sheds. Spikes are installed on farm chimneys to stop birds perching, and fly netting is widely used. Air inlets are also covered to stop light leaking at night, which will attract insects.

The report also notes that in Norway, Sweden and Denmark, campylobacter-positive flocks face a price penalty. “But, as well as running the risk of paying a penalty, producers also regard acquiring a campylobacter-positive flock as some form of failure on their part. For this reason, they embrace good biosecurity.”

As for age of slaughter, Mr Strydom observes that, the older a flock is at slaughter, the more likely it is to test positive. This partly relates to the fact that the disease spreads quickly and, when infection enters a shed, within a week the whole flock will be contaminated.

“I believe that, if we stop thinning, the birds will grow faster and thus they will be able to be processed at a younger age, reducing the number of campylobacter-positive flocks.

“Our industry cannot continue to sell a product that could cause people to become ill, and have no accountability,” adds Mr Strydom. “Other countries have managed to successfully reduce the number of campylobacter-positive flocks. I hope by investigating what they have done, we can come up with interventions that will make a difference in the UK.”


 * “International strategies to reduce the incidence of Campylobacter in broiler flocks” was sponsored by the Nuffield Poultry Meat Award Syndicate (Aviagen, Cobb and Hubbard) and is available to download from the Nuffield International website.