Further controls needed to limit Campylobacter food poisoning, review finds

An expert review into the sources, spread, and control of Campylobacter has found that further interventions are needed to better limit the spread of food poisoning caused by the bacteria.

The review has been led by Professor Matthew Goddard, Professor of Population and Evolutionary Biology at the University of Lincoln, UK, and is part of an Oxford Martin Restatement – a review of the natural science evidence base underlying areas of current policy concern and controversy. This is vital as the prevalence of antibiotic resistant Campylobacter is increasing in the UK and has been designated a ‘high priority’ pathogen by the WHO.

The Restatement, undertaken in partnership with the Oxford Martin School at the University of Oxford and co-authors at The Universities of Oxford, Cambridge, Newcastle, Liverpool and the Royal Veterinary College, found that despite falling Campylobacter levels on chicken over the past five years, levels of illness have not changed.

Around 3,500 people in Britain are hospitalised every year with campylobacteriosis – food poisoning caused by Campylobacter contamination representing the greatest number of hospitalisations of any food-borne disease in the UK and the number one cause of bacterial food poisoning.

The Restatement concludes that further interventions are needed – but no single solution will provide perfect control. Other key conclusions of the restatement include that there was no clear evidence that long-term use of chlorine rinses, as practiced in the USA, lowered levels of the bacteria or food poisoning caused, and that a broader series of control measures had strong evidence for its overall effectiveness as a package.

The UK’s poultry industry has successfully reduced the quantity of retail chicken testing positive for Campylobacter from 73% in 2014 to 40% in 2018. However, cases of illness have not reduced over the same period. The Restatement highlights the evidence that beef, lamb and pork are implicated as carriers of the bacteria and potential causes of food poisoning and so wider control measures may be needed.

Professor Goddard said: “We cannot be sure why the UK has its peak of campylobacteriosis in May and June – it might be the warmer temperatures accelerating its growth or food-safety issues at barbecues. We do know the biggest risk is poor food hygiene, cross-contamination and undercooked meat – particularly, but not just, chicken. From reviewing evidence from around the world, we see that there is no single processing solution, type of farming, or public education intervention that can solve this.”

Professor Sir Charles Godfray, Director of the Oxford Martin School added: “Governments and the WHO have rightly identified Campylobacter as a key concern; globally it caused around 166 million cases of illness and 37,600 deaths in 2010. But it is a complex area with a difficult to navigate evidence base. What we’ve tried to do here, and what we do with all our restatements, is lay out and classify the evidence in easy-to-read, policy-neutral terms to help public health officials, food and farming bodies, and policymakers understand the issue and make their own decisions.”

Professor Goddard concludes: “If people want to protect themselves from campylobacteriosis food poisoning they can focus on food hygiene. Make sure your food is cooked properly, and be careful not to contaminate cooked meat with bacteria from raw meat – especially at barbecues where food at different stages of cooking might be on the same grill rack and handwashing facilities may be further away. Cleaning our hands, keeping raw and cooked meat well apart, and not putting cooked food on plates that have held raw food is something we can all do to make a difference.”

The full paper, ‘A restatement of the natural science evidence base regarding the source, spread and control of Campylobacter species causing human disease’ is available at http://www.oxfordmartin.ox.ac.uk/policy/restatements/ https://royalsocietypublishing.org/doi/10.1098/rspb.2022.0400#d1e497.