Some British supermarket pork has been infected with a potentially fatal superbug, an investigation has found.
Tests discovered that more than 10% of sampled pork products, including joints, chops and mince, were infected with bacteria that showed resistance to a “last resort” antibiotic used to treat serious illnesses in humans. The contaminated products included some pork sold under the “Red Tractor assured” label and RSPCA-assured and organic products.
The superbug is a variant of the enterococci bacteria that can cause urinary tract and wound infections, among other illnesses. In the most serious cases the bacteria can infect the bloodstream, heart and brain.
It has become resistant to being treated by some types of antibiotics, which means some of the medicines a doctor might normally prescribe would have no effect for treating illness.
Drug-resistant strains of bacteria are a significant health concern, with rates known to be rising across Europe. There are many reasons that bacteria are developing ways of getting around antibiotics, but one key issue is that antibiotics have been widely used in livestock production to treat and prevent disease, particularly on factory farms.
These farms can act as incubators for potentially fatal drug-resistant diseases in humans, and antibiotic resistance is now considered one of the world’s biggest public health threats. A UK government review on antimicrobial resistance in 2016 estimated superbugs kill at least 700,000 people worldwide every year, which could rise to 10 million extra deaths by 2050 if no action is taken.
The new testing, shared exclusively with the Bureau of Investigative Journalism and the Guardian, suggests the enterococci superbug is more widespread in UK meat than previously thought. A government survey published in 2018 found it in one in 100 pork and poultry items tested. But the new tests found it in 13 of 103 samples and also detected it in organic meat, despite the fact that organic farmers use significantly less antibiotics on their animals.
Experts said the “worrying” revelations reinforced the need for more surveillance.
Tim Lang, a professor emeritus of food policy at City, University of London, said: “These findings suggest that antibiotic use is by no means under control in parts of the meat industry. Buying any food is a trust relationship; no consumers have X-ray specs to see what these findings show. There’s no label.”
In response, a spokesperson for Red Tractor said its certified pig farms were required to use antibiotics responsibly, under the direction of a vet.
The RSPCA said: “As an animal welfare organisation, we hope and would expect to see that higher welfare systems would require lower antimicrobial use which, in turn, would lower the risk of developing antimicrobial resistance. This would improve the lives of farm animals as well as safeguarding human health.”
Gareth Morgan, the head of farming policy at the Soil Association, said: “Lower levels of antibiotic resistance in the organic produce can be explained by the very strong restrictions on antibiotic use in organic farming.
The Veterinary Medicines Directorate, the government department responsible for antibiotic use on farms, said in a statement: “We are committed to reducing unnecessary use of antibiotics in animals and it remains our intention to strengthen our national law in this area.”
The FSA points out that cooking meat throughly should kill most bacteria, or reduce it, and handling it hygienically will help to reduce the risk. It should always be kept separately in the fridge, and hands, knives and boards should be thoroughly washed after handling.
In what is believed to be the first UK study of its kind, the campaign group World Animal Protection commissioned Fera Science to examine the prevalence of antibiotic-resistant enterococci in pork produced under three different food assurance schemes as well as non-assured products.
Researchers bought 103 pork samples – 22 labelled as Red Tractor, 27 each from RSPCA and organic schemes, and 27 with no assurance label – from Yorkshire supermarkets and online shops. All were from British farms, except for products carrying no assurance label.
The meat was then analysed for enterococci bacteria and the 25 positive samples were tested for antibiotic resistance. Of the infected samples, all but two contained enterococci resistant to at least one antibiotic.
Of the contaminated samples, 13 were resistant to the antibiotic vancomycin. Five of these were Red Tractor products, four non-assured and two each were organic and RSPCA. Vancomycin – part of the glycopeptide class of antibiotics – is often referred to as a “last resort” antibiotic because of its importance in treating the most serious and life-threatening infections.
The Glycopeptide avoparcin was widely used on farms to fatten livestock faster until the EU banned this in 1997, after the practice was widely blamed for spreading superbugs from farm animals to people.
Despite the ban, studies have suggested the use of other antibiotics in livestock production has contributed to the persistence of glycopeptide resistance in bacteria carried by farm animals.
Some enterococci samples were found to be resistant to other classes of drugs classified as “critically important” to human health. Some of these medicines, including fluoroquinolones and macrolides, continue to be used on British pig farms, despite calls for their usage to be curtailed.
A Red Tractor spokesperson said: “Our standards only permit the use of the highest-priority critically important antibiotics as a last resort, when absolutely necessary to protect pig health.”
Although the UK pig industry says it has reduced antibiotic use on farms in recent years, concerns have been raised that as one type of drug has been phased out, farmers and vets have turned to others rather than fully address inadequate welfare standards.
Cóilín Nunan, a scientific adviser at the Alliance to Save Our Antibiotics, said: “Much higher welfare standards can reduce animal stress and disease, and eliminate the need for most antibiotic use in pig farming.”
The Soil Association said glycopeptides were never used in organic farming. One possible explanation, it said, for vancomycin-resistant bacteria being found on organic meat was because it had spread to organic farms via the environment, including the water supply.
More than half of all antibiotics globally are used in animals, and reducing drug use in farming is seen as critical to helping combat the problem.
Earlier this year the EU brought in tougher regulations that banned the feeding of antibiotics to groups of healthy animals. The UK has so far failed to commit to similar rules, prompting warnings that it risks falling behind in combating the spread of antibiotic-resistant disease.
Mark Holmes, a professor of microbial genomics and veterinary science at the University of Cambridge, urged the UK government to adopt the EU standards: “Antibiotic stewardship in UK agriculture has been considerably improved over the last few years but there is always room for improvement.”
Lindsay Duncan, the farming campaigns manager at the conservation charity World Animal Protection, said: “The UK government needs to end the routine use of antibiotics on farm animals, as the EU has recently done, and to acknowledge that a reduction in animal product consumption is needed to address the countless issues caused by factory farming.”