WASHINGTON - Increasingly, companies, retailers and consumers are pressuring the U.S. Food and Drug Administration (FDA) to act on the rising incidence of food fraud, the Washington Post reports.

Examples of food being mislabeled abound: "sheep??s milk" cheese really being made from cow??s milk; "Sturgeon caviar" being Mississippi paddlefish; grouper, red snapper and flounder actually catfish fillets from Vietnam; and honey diluted with sugar beets or corn syrup sold as 100 percent pure.

This type of "food fraud" has been found in fish, fruit juice, maple syrup, olive oil, spices, spirits, vinegar and wine. Those affected by the fraud include consumers and companies such as E&J Gallo and Heinz USA.

John Spink, food and packaging fraud expert at Michigan State University, said that between 5 percent and 7 percent of the U.S. food supply is affected by food fraud. "We know what we seized at the border, but we have no idea what we didn??t seize," he said.

The FDA has the job of ensuring accurate labeling on food, but the agency has been focusing on preventing food contamination lately. The emergence of DNA testing, coupled with isotope ratio analysis, makes it easier to detect fraud in food.

"We put so much emphasis on food and purity of ingredients and where they come from," said Mark Stoeckle, a physician and DNA expert at Rockefeller University. "But then there are things selling that are not what they say on the label. There??s an important issue here in terms of economics and consumer safety."

The FDA would like to implement a surveillance program that would let regulators know about possible fraud, said Jennifer Thomas, director of enforcement at FDA??s Center for Food Safety and Applied Nutrition. On a regular basis, the agency exchanges information with two other agencies that also monitor seafood fraud. The FDA has taken action in recent months against food fraud.