Food fraud is a common issue all over the world. Inspectors of veterinary services and fraud inspect seafood products at the Rungis international market, located near Paris. Martin Bureau/AFP/Getty Images

In just under four minutes, this story (National Public Radio, USA) gives a cogent briefing on one dimension of food transparency, a topic commonly addressed in these pages:

If you’ve been following any of the big news stories on food fraud lately — you’ll know that it’s tough to know what exactly is in our food — and where it’s been before it makes onto our dinner plates.

Earlier this year, Wal-Mart was sued for stocking tubs of Parmesan cheese that contained wood pulp filler. Olive oil is often mixed with sunflower oil and sold as “extra virgin.” And you might recall the great European horse meat scandal of 2014: Traces of horse meat were found in Ikea meatballs and Burger King beef patties, in cottage pies sold at schools in Lancashire, England, and in frozen lasagna sold all over Europe.

And that’s “just the tip of the iceberg,” says Chris Elliott, the founder of the Institute for Global Food Security, a laboratory in Northern Ireland that tests food from all over the world in order to uncover fraud.

“Many, many forms of food fraud manifest themselves in different parts of the world virtually every day of the week,” he says. Globalization, and complex supply chains provide fraudsters with ample opportunity mess with food products.

NPR’s Rachel Martin asked Elliott how his lab goes about tackling this daunting problem.

So are people deliberately cheating the global food supply chain?

It’s absolutely cheating. But it goes beyond cheating — this is criminal activity, very well organized criminal activity, with people making a huge amount of money out of fraud in food systems

How much money are we talking about here?

Nobody really knows, but the world trade in groceries is about $11 trillion. And the level of fraud is somewhere between 5 and 10 percent of that…

Read or listen to the whole interview here.