Is honey fraud overestimated? Study says maybe so

Reports of honey adulterated with sugar syrups have been widespread in the last few years, but may be based on flawed methods, according to UK researchers.

Two research papers published in Nature by scientists at the UK Government Chemist and the Institute for Global Food Security (IGFS) at Queen's University Belfast suggest that the complexity of honey challenges currently-used analytical methods like NMR spectroscopy, which may lead to erroneous findings.

The work was prompted by an article in the Daily Mail in 2020 which claimed that own-brand honeys from leading UK supermarkets were bulked up with cheap syrups made from rice and corn, without the retailers' knowledge.

The report prompted the Food Standards Agency (FSA) to ask the Government Chemist to investigate the methods used in the research behind the story.

"The summary opinion of the reporting laboratory in each of the Certificates of Analysis that were examined was unequivocally that the samples were non-compliant," says QUB's Prof Michael Walker.

"However, our critical examination of the data revealed a much more nuanced picture from which it is currently difficult to draw such a definitive opinion."

That's not to say there is no fraud – in fact, the scientists suggest that there are signs of "sophisticated adulteration" by ingenious fraudsters trying to hide their activity from lab testing approaches.

In the absence of universally-agreed lab techniques for testing honey authenticity, the authors suggest a forensic approach to testing honey samples based on "evaluative reporting" and a method used in criminal forensic law known as the likelihood ratio (LR) that would be a "better basis to identify and address fraud," said Walker.

Put simply, LR means the chances that a sample is adulterated is weighed against the chances that it is not, taking into account multiple factors rather than – for example – the presence of a honey marker compound like diastase at a lower than expected concentration, or caramel at a higher than expected level.

This weight of evidence approach is clearly much more complex, but could be used to avoid erroneous results and media reporting of an issue that may be overstated. It could also be applied to other foods widely held to be vulnerable to fraud, like olive oil.

"Honey adulteration is notoriously difficult to identify correctly. Multiple disputes have arisen around what is fake and what is truly authentic," says Chris Elliott, professor of food safety at IGFS.

"This latest research is an important step in advancing the rigour of the incredibly detailed science behind the correct identification of honey adulteration by adopting a methodology based on a forensic-science approach."

The two Nature papers can be found at the links below:

Honey authenticity: the opacity of analytical reports - part 1 defining the problem; and 

Honey authenticity: the opacity of analytical reports—part 2, forensic evaluative reporting as a potential solution.