Transcript for Food Fraud? Watchdog Group Raises Concerns
OK let's be honest when it comes to what's in your food most surprises are not welcome ones. -- if you can think you can trust the labels of the products you -- the grocery store. An alarming new study might make you think twice. Because from all of oil to copied to spices instances of so called food fraud are cropping up nationwide. ABC's Jim I'll love brings us the reports. A trip to the grocery stores should be simple and straightforward. Anything they put in there should be lists -- over ingredients label. But how do you know what's on the label is what you're actually getting. In a study to be released later today. The US -- cope -- convention and independent nonprofit lab with a mission of raising food standards says in many cases you can't. -- -- comprehensive review of food fraud finds the reports of fraudulent ingredients in our food. In grainy it's not label being used as cheap substitutes are up 60%. Over last year's review. Food products are not always what they purport to be -- its profit for in this case -- That. Seems to believe the driver for a lot of human actions -- -- ground black pepper Camby adulterated. It's enough to make you wonder who thinks of this stuff stems stark -- everything that looks greatest spectacles. Appears to be ground black pepper the scientists at USP want to know what's really on grocery shelves not just what the label says is in the bottle -- box. What's actually inside an -- testing paprika spices they found are often not what they see. Have become part of it -- color appeal but nice -- let color. There are synthetic. -- invest field is available that mimic that -- very nicely. But sometimes those industrial dyes could not only make paprika -- more attractive to BI. They can harm the buyer. Those guys typically. Carcinogenic or at least presumed carcinogenic. An industry watchdog group estimates 7% of the American food supply contains fraudulent ingredients the most common frauds at the supermarket. Liquids and ground food are easiest to doctor expensive extra virgin olive oil. Deluded with cheaper vegetable oils costly pomegranate juice -- -- alteration is widespread. Some brands diminished by great or pear juice -- fraud black pepper and paprika. Cut would stems -- cheaper spices. Tea bags filled with fern leaves in common lawn grass. Pure lemon juice reduced by sugar and water the National Consumers League did their own test in May of 2012. Well we tested four bottles of let me just one hit 10% -- -- that it had a 100%. Another had 15%. And another had 25. Analysts -- every 10% in case they were all labeled a 100%. A 100% and that they can really make a lot of money that went well if you think about it you know twenty limits cost a lot of money five limited's -- complex. We went shopping with consumer advocate Sally Greenberg who showed us there is really very little consumers -- -- -- when looking on the shelves for fake flu. Here's extra virgin olive oil. We're not gonna children -- but this extra virgin olive oil is five dollars and fifty cents. That's pretty cheap for extra virgin olive oil and something that should raise some eyebrows for consumers Greenburg says. Consumers need a cop on the beat in since the FDA can't test everything. They should be looking at the USP database and targeting the foods most often -- both the FDA and Grocery Manufacturers Association. Tell ABC news they take the new findings seriously and monitor grocery aisles for food fraud. It shouldn't be hard to find high school students supervised by New York's Rockefeller University. Found alarming results in testing done over the last three years. 16%. Of the grocery store food they DNA tested from expensive sheep's milk cheese and had a -- how DNA -- -- To caviar that wasn't made of sturgeon -- to pet food with no meat. All had counterfeit ingredients. In something supposedly as soothing as an organic tea. Was jammed with all kinds of bothersome -- not mentioned on their -- Rules if you were to take report the -- -- a lot of dried things and there are it's it's hard to tell what they are -- you can use DNA it to. Texas test them some had our firm. In its some have lawn grasses to be called goose -- How do you who use this information. By knowing what's at the top of the list of fakes being suspicious of dramatically low prices on. Normally expensive items. And by buying brands -- incentive to make you -- return customer. Not fake you out for Nightline I'm Jim Koppel in Washington.
This transcript has been automatically generated and may not be 100% accurate.