With fraud on the rise, do you know the real origin of your food?

These days, we're increasingly concerned with the origins of our food. We like to know that our eggs are free range, our fish is from a sustainable source and we may want to choose organic vegetables, or those grown locally. For these reassurances, we're prepared to pay a bit more. But are we always getting what we're paying for?

For many of us, the possibility that what we're buying in our weekly shop isn't what it says on the label will never have crossed our minds. Yet food fraud, a crime that has been around since Roman times if not longer, is a growing concern as a result of the globalisation of food production and the potential that rising food prices offer to criminals.

"A lot of food fraud goes on, but there's little awareness of it because the only data that exists relates to frauds that have been exposed," says Chris Elliott, professor of food safety at Queen's University, Belfast, which is hosting an international "food integrity" conference exploring the subject next month.

One recent estimate – based on Food Standards Agency (FSA) surveys of a number of different individual foods – suggested that food fraud could affect as much as 10 per cent of the food we buy, he adds. Which is why a growing emphasis is now being placed on food fraud detection through investigating and prosecuting alleged fraudsters, and developing sophisticated tests to determine whether a product is what it is claimed to be.

"Though food frauds can take a variety of forms – from brand counterfeiting to "honey laundering" [falsely claiming that a product, often Chinese honey, comes from somewhere else to justify a higher price] – all follow the single principle of misleading consumers for financial gain," says Dr John Spink, associate director of the Michigan State University anti-counterfeit and product protection program, who is working to define food fraud's threat to public health.

"Every time there's an exchange of goods and services along the food supply chain there's an opportunity for fraud – when food passes from producer to processor, or from manufacturer to distributor," he explains.

"Though expert perception is that the volume is probably the same per head of the population it has been since Roman fraudsters watered down wine, globalisation and our growing willingness in the West to pay a premium for certain products has made food fraud a pressing concern."

Take saffron. The costliest of spices, it emerged just last month as the focus of a UK investigation into routine adulteration of the pure spice with worthless parts of the saffron crocus. In a similar scam a few years back, batches of basmati rice – which is more than twice the price of ordinary varieties – were found to have been cut with cheaper varieties, though Rice Association figures show the problem has declined over the past few years.

Food fraud isn't just confined to dry goods, though. In Cumbria, for example, a recent investigation led to the successful prosecution of fish fraudsters just before Christmas. "Fish fraud is a recurring problem – as it is in many part of the country where itinerant fish sellers trade door to door," Angela Jones, trading standards manager for Cumbria council explains. "We found examples of cheaper species such as hake or coley being sold as monkfish or sea bass, with no indication of origin, or even a 'best before' date."

The growing preference for free-range produce provides another opportunity for fraudsters. Last year, a Midlands businessman was jailed for a £3m scam in which he passed off around 100 million battery eggs as free range or organic to retailers including Tesco and Sainsbury's. Organic food that isn't, meanwhile, has been another problem in other parts of the UK – including the posher parts of the London borough of Haringey.

"Misleading claims around the origin of food have become a growing concern," according to Tendy Lindsay, Haringey council's senior trading officer. "It's a problem that's led to investigations into reports not just of fraudulent organic claims, but also of halal products that are anything but."

Other recent investigations in the borough have focused on alcohol – illicitly-produced drinks passed off as familiar brands, and fake champagne sold under a made-up name. "Traditionally, there's been a perception there's not much fraud in food," Lindsay adds. "But in our experience it's a problem that's becoming more apparent as more investigations are undertaken and more prosecutions are being made."

Despite staff numbers that are falling in the face of growing pressure from public sector spending cuts, Lindsay, and trading standards officers such as her, are the front line in food fraud detection. But they are not working alone. For a start, their efforts are now co-ordinated by the FSA's dedicated Food Fraud Advisory Unit. "Our aim is to co-ordinate and support local authority enforcement officers," FSA food fraud team head, Cathy Alexander, explains. "And we do this in a number of ways but chiefly by sharing and gathering information. Our food fraud hotline allows people to call in with their concerns, and our national database helps pool information about tip-offs, investigations and emerging trends."

Many leading retailers, too, now have similar checks and balances in place. "We've extensive processes to ensure that our customers are getting exactly what they are paying for and to ensure food fraud does not occur in our supply chain," says a spokesman for Sainsbury's. These include a database of every product, supplier, ingredient and associated manufacturer to ensure everything is traceable; careful vetting and constant monitoring of all suppliers and ongoing surveillance by "mystery shoppers" in-store, supported by spot checks and lab testing.

Scientists, meanwhile, have become another critical part of our defence against the food fraudsters, with research facilities regularly undertaking work on behalf of retailers and public bodies to authenticate the precise make-up or provenance of suspect foods or drinks.

"Determining the geographic origin of a piece of food is difficult but can be done," Professor Elliott explains. "We can now show, for example, not only if an egg was produced in Ireland, but where it was produced to the nearest five miles by analysing the unique elements in what the hen ate or drank. And there have recently been developments in testing to distinguish free range from cage-reared birds."

The test on the egg, known as isotopic profiling, can also be used on wine – a product where fraud has become a big concern, Some Italian producers are now considering placing isotopic fingerprints on wine labels as proof of provenance, he says.

What none of these measures can do, of course, is tell a shopper if what they are about to buy is a fake. Which is where, arguably, the final and, arguably, most important line of defence comes in: consumer vigilance. A mixture of awareness and basic common sense among shoppers is essential.

Investigations and disincentives such as fines or prison sentences are all fine and well, but the key to beating the problem is ensuring food fraud doesn't pay, says Dr Spink: "The biggest disincentive is making it hard for them to make money out of it. Which is why my advice to anyone is: identify suppliers and brands and retailers with a clear, vested interest in keeping customers happy and encouraging repeat purchases."

Nicolas Frankcom, a senior researcher at Which?, adds: "It's hard for consumers to keep ahead of unscrupulous traders, and food fraud gets ever more sophisticated, which is why it always pays to look closely at the ingredients list to get a better idea of what you are really buying. And if you suspect something is wrong, report it."

Buyers beware: what to look out for

Counterfeiting

What is it? Unauthorised copying of a popular food or drink with the fake sold with lookalike labelling and packaging.

Such as? Salford Trading Standards seized 436 bottles of counterfeit alcohol ahead of last year's World Cup. The haul included fakes of many familiar brands.

How to tell: Label or branding that doesn't look right or differences in taste.

Species swapping

What is it? A cheap variety of an item sold as a premium variety to fool the shopper into paying more.

Such as? One in ten fish sold as "wild sea bass" and "wild sea bream" and one in seven described as "wild salmon" were really farmed fish, an FSA survey found.

How to tell: This can be almost impossible for the shopper to detect – which is where lab tests such as DNA profiling can play a role.

Simulation

Such as? Diluting a legitimate product with a cheaper ingredient then selling it at the original (higher) price.

Such as? Adulterated olive oil – ordinary oil coloured with chlorophyll to resemble virgin, for example – was recently described as "the biggest agricultural fraud in the EU".

How to tell: Again, tricky. But lab tests can now detect fraud by precisely identifying specific varieties of raw ingredient.

Ethical deception

What is it? Exploiting our willingness to pay more for ethical products by mislabelling non-ethical alternatives.

Such as? Fake organics – one scientist recently estimated the volume of sales of organic produce (which can command a 20 per cent price premium) is twice the amount of organic food items produced.

How to tell: Lack of any official organic certification, though not all unmarked produce is necessarily fraudulent.

Origin fraud

What is it? Intentionally misrepresenting where a product has come from to mislead us into paying more.

Such as? One recurring fraud involves renaming South American beef as European, which can double the price it can command.

How to tell: Impossible by eye, though "isotopic profiling" can reveal the chemical fingerprint left by elements in the environment where that animal lived.

And what to do

Be on guard for any unexpected taste, texture or smell – shoppers who reported a metallic after-taste prompted a Which? investigation that highlighted possible fraud involving higher quality Chinese pine nuts replaced with a cheaper substitute.

Careful checking of the labelling or packaging can also highlight fraud. If anything looks unclear or misleading ask questions, and if you don't get the reassurance you expect then walk away.

Always buy from somewhere reputable, and look for official certification to back up product claims – the Soil Association mark showing that a product is organic, for example. When it comes to farmers markets, look out for Farma mark currently held by around one third of the UK's farmers markets and administered by the National Farmers' Retail Markets Association – it denotes that the produce sold is local and that the vendor was involved in its production.

If in doubt, contact your local authority trading standards officer or call the Food Standards Agency's national Food Fraud Hotline on 020 7276 8527.