A quarter of samples of dried oregano have been found to contain other ingredients in the latest food fraud.
The study found 19 out of 78 samples of the herb contained added ingredients – most commonly olive and myrtle leaves – which made up between 30% and 70% of the product.
Professor Chris Elliott, the director of the Institute for Global Food Security, who authored the report into food fraud following the horsemeat scandal, examined samples from a range of shops in the UK and Ireland and from online retailers.
The results have been reported by Which? and are now being shared with the Food Standards Agency.
Which? described the findings as “the latest in a long line of food frauds”.
Last year the consumer group found that 40% of the lamb takeaways it tested contained other meat and one in six of the fish it bought from chip shops was not what had been ordered.
Which? executive director Richard Lloyd said: “It’s impossible for any shopper to tell, without the help of scientists, what herbs they’re actually buying.
“Retailers, producers and enforcement officers must step up checks to stamp out food fraud.”
Elliott said: “Based on intelligence received we decided to determine if there are issues with the authenticity of oregano supplied in the UK and Ireland.
“Clearly we have identified a major problem and it may well reflect issues with other herbs and spices that enter the British Isles through complex supply chains.
“Much better controls are needed to protect the consumer from purchasing heavily contaminated products.”
Last year Elliott called for a national food crime prevention network to help protect consumers from food fraud in a government-commissioned report following the horsemeat scandal.
