The University of Reading has published a study that suggests low-power blue light could reduce food poisoning caused by raw chicken.
Campylobacter is the most common cause of bacterial food poisoning worldwide, said the University of Reading, with the UK reporting hundreds of thousands of cases each year, costing an estimated £700 million annually in healthcare and lost productivity.
Researchers from Reading, working in collaboration with the Animal and Plant Health Agency, tested a technique known as violet-blue photodynamic inactivation (VB-PDI) against 64 different strains of Campylobacter, which is found in around three-quarters of all raw chicken sold in the UK. Every single strain was killed by the treatment, regardless of species or antibiotic resistance profile.
The findings were said to build on previous research that showed blue light treatments could work more effectively than treating chicken with chlorine to kill off specific strains of bacteria. The University of Reading highlighted that chlorinated chicken is common in the US, but is not commonly found in Europe, and is a “high-profile example of differing food standards and trade barriers” between US and Europe.
Campylobacter can also be killed through cooking, but cross-contamination is thought to be the main route of infection, with symptoms ranging from stomach cramps to fever, nausea and bloody diarrhoea, typically lasting about a week.
VB-PDI works by shining a safe, visible violet-blue light onto bacteria, causing molecules naturally found inside their cells to produce lethal levels of destructive compounds called reactive oxygen species. Crucially, said the researchers, the method needs no physical contact with the food and no added chemicals, making it a “promising option” for use on poultry carcasses in processing plants after slaughter, before products reach consumers.
The researchers estimated that if the technique could reduce contamination on chicken carcases by a factor of 100, the proportion of highly contaminated carcases reaching retail could fall from around one in ten to one in 50.
There was no reported evidence that the bacteria could develop resistance to the treatment, and strains that were already resistant to antibiotics were killed just as effectively as fully susceptible ones.
When one strain was repeatedly exposed to the light over 15 rounds in the laboratory, in an attempt to force resistance to evolve, no increase in tolerance was seen.
Dr Aidan Taylor, from the University of Reading and lead author of the study, said: “Campylobacter is a genuinely nasty bug, and its sheer abundance in the food chain, combined with rising antibiotic resistance, makes it a really difficult problem to tackle.
“What’s exciting about this light-based approach is that it doesn’t rely on chemicals or antibiotics at all, so it sidesteps the resistance problem entirely. We’ve shown it works against a wide range of real-world strains taken directly from UK poultry, including the multi-drug-resistant strains that worry us most, and we can’t find any evidence that resistance could evolve. That combination of broad efficacy and durability is what makes this such a promising option for cutting contamination before chicken ever reaches someone’s kitchen.”
The research team argued that VB-PDI could be a low-cost option for poultry producers due to its use of simple, low-power LEDs with a long lifespan, and said it could also support low- and middle-income countries where food safety infrastructure is limited.
The Animal and Plant Health Agency surveillance programme aims to provide a detailed picture of the Campylobacter strains circulating in UK poultry, allowing scientists to test the technology against a real diversity of bacteria, rather than laboratory strains alone. The researchers said further trials on naturally contaminated poultry carcases in real processing settings are now needed before the technology could be rolled out commercially.
Dr Samuel Connelly, from the Animal and Plant Health Agency, who co-led the research, stated: “The consistent results observed across multiple species and resistance profiles are highly encouraging. While further evaluation using contaminated meat samples is required, the simplicity and adaptability of this technology suggest that it could be implemented at various stages of the food production process. Such application has the potential to reduce the prevalence of Campylobacter within the food chain and, consequently, contribute to a reduction in the incidence of foodborne illness.”
The full report can be accessed here.
