A recent food fraud study in the UK reveals 25% of 78 samples of dried oregano bought at various retailers were found to be mixed with other ingredients such as olive and myrtle leaves.
The study conducted by the Institute for Global Food Security director Chris Elliott, whose insights were revealed exclusively to Which? show that these 'other' ingredients were found to constitute between 30% and 70% of the product.
Elliott sampled oregano from a range of shops in the UK and Ireland, and from online retailers using mass spectrometry, which identifies compounds by their atomic composition.
Commenting on the results, professor Elliott said: "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."
Which? is now sharing the results with the Food Standards Agency.
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.'
Trace One executive vice-president of Global Business Development Shaun Bossons responded to the study results: "While consumers are right to be alarmed, this survey should be equally worrying for retailers. Quite frankly, 21st century shoppers are more savvy than ever; they know the options that are available to them, and they aren't afraid to act if they feel that the industry has let them down.
"In the wake of horsemeat, potential nut contamination and a whole host of other food fraud scandals, this could be the last straw that breaks many shoppers' trust in the industry. Checks and balances must be in place to ensure this doesn't happen; regardless of where any fraud occurred and who is ultimately responsible.
"To keep their customers' trust, retailers must be able to prove that they are whiter than white. This means having total transparency over the supply chains of their products, and being able to demonstrate the provenance of each one as required.
"In situations where contamination or fraud occurs, even when completely out of the retailer's control, they must be able to act swiftly, decisively and transparently, removing affected products from the shelves, issuing recalls, and sharing their actions and knowledge at every step. This demands complete collaboration up and down the supply chain, but retaining consumer trust in the wake of food scares makes it a small price to pay."
Meanwhile, Schwartz, the leading brand from the stable of industry major McCormick & Company, Inc, has vouched for the purity of its products.
McCormick corporate vice-president global quality assurance Roger Lawrence said: "We are pleased this issue is getting attention and believe it's important consumers learn all spices and herbs aren't created equal.
"While Professor Elliott's study found as much as 30 to 70 percent non-oregano material in other brands, Schwartz oregano is simply oregano delivering 100 percent pure flavour. Our oregano contains no other green leaves like myrtle, cistus and olive."
McCormick insisted that its premium oregano can be traced from field to bottle, minimizing chances of added ingredients and contamination.
