A potentially dangerous wave of food fraud affecting everything from olive oil to tuna, spices and pomegranate juice has been exposed.
Extra virgin olive oil is being diluted with cheaper vegetable oil, while tea bags might be bulked up with lawn grass or fern leaves, according to US researchers.
Apparently healthy white tuna on a menu may actually be the less-expensive escolar, a fish that has been banned in many countries because of its links to food poisoning.
Food fraud: Some manufacturers are selling cheap escolar - a fish that has been linked to a type of food poisoning - masquerading as tuna, a report warns
There is evidence from America that manufacturers are secretly adding cheap pear and grape juice to pomegranate, which is highly sought after as a health drink.
While spices such as black pepper, paprika and saffron may be bulked up with other plant material and coloured with industrial, and potentially dangerous, dyes.
The warnings come from the US Pharmacopeial(correct) Convention, an independent scientific body which sets quality standards for food and medicine.
The organisation says many foods contain ingredients which consumers would not expect to have bought - akin to the recent scandal in Britain involving horse meat being found in beef burgers.
According to the report, called the Food Fraud Database, many of the added substances are less expensive and some are harmful.
The situation mirrors warnings from British trading standards chiefs who say the current economic climate means manufacturers, retailers and restaurants may be more inclined to cut corners.
British experts have found that honey, cheese, eggs, organic meat and produce, Basmati rice, even fish and chips are not necessarily what they seem.
Just before Christmas one British firm was fined more than £20,000 for passing off a cheap pesto sauce as something far more gourmet.
Stark Naked Foods claimed its pesto was made with extra virgin olive oil and Grana Padano cheese, when in fact it was sunflower oil and a cheaper Latvian cheese.
'Fillers': Pomegranate juice, left, has been said to slow the spread of cancer, while olive oil, right, can help lower cholesterol - but both have appeared on a list of foods that often contain unexpected additives
At the same time, pubs and restaurants are not immune to boasting of offering local quality food, when this actually means the nearest supermarket or wholesaler.
One estimate suggests British families are wasting as much as £7billion a year paying over the odds for food that has been faked in some way.
There are cases of imported beef from Zebu cattle, which have a distinctive hump on their neck, being imported from south America and sold in pubs as ‘British’.
Meat from cross-breed cattle containing Zebu genes from Brazil is cheaper than British beef, however critics point out that it can also be much tougher.
Vast quantities of cheap honey is being imported into Europe from China and used to bulk up other types in a scam that has become known as ‘honey-laundering’.
In some cases honey is not honey at all, but rather corn syrup or just sugar.
Butcher shops and leading restaurants have been found selling conventional meat and produce as organic, along with a premium price.
In the past, even Harrods has been found selling farmed salmon as wild.
But the fakery does not stop at salmon, for some fish and chip shops have been prosecuted for passing off Shark Catfish, which is farmed in the rivers of Vietnam’s Mekong delta, as battered cod.
The fish sells for less than half the price of real cod in wholesale markets, however chip shop customers are being charged as if it is the real thing.
Director of policy at the Trading Standards Institute, Andy Foster, warned that a squeeze on spending means his members find it increasingly difficult to stem the problem.
Mr Foster said: ‘Wherever there is a few pounds to be made someone will try to exploit it.
‘In times of recession, when people are looking for a bargain and going to different places, that is where you start to find more fraud introduced to food.’