Recent reports have highlighted how meat processors use the enzymes, formally known as transglutaminase and beef fibrin, to bind smaller cuts of beef and pork and form consistently sized, uniformly shaped larger steaks.

The U.S. Agriculture Department says the enzymes, which are also used in imitation crabmeat and some pasta and dairy products, must be listed on the ingredient label of anything containing them.

But because most meat containing the enzymes is sold to the food service industry, critics say few consumers know they're eating them.

Critics have also suggested the enzymes, which are derived from beef plasma and other sources, could be used to deceive consumers by turning smaller, inexpensive cuts of meat into what appear to be premium cuts.

Hoping to avoid the fallout over the use of "pink slime" in ground beef, the American Meat Institute hosted an hour-long conference call on Thursday with representatives of Ajinomoto North America and Fibrimex, the two companies that manufacture the enzymes.

They said the enzymes find their way into only a fraction of the meat sold in the country. A typical use, they said, was to help bind two, triangular-shaped beef tenderloins together to create a uniform filet that might wind up being served in a restaurant, casino or banquet hall or on a cruise ship.

Mark Dopp, the Institute's top lawyer, called allegations the glue is being used to make chuck steak look like filet mignon "unfounded."

Some critics, like William Marler, a Seattle attorney who specializes in food safety litigation, say that while the enzymes themselves are harmless, consumers who eat steaks formed with them could be at higher risk for food-borne illness.

"If you've got a steak that has meat glued together, the only way you can make that product safe is to cook it well done," Marler said on Thursday.

"But since consumers don't know that, they won't know they have to order it that way. That's the problem."

Dana Hansen, an associate professor of meat science at North Carolina State University who participated in Thursday's call, said such concerns were unfounded.

He said the USDA recommends meat containing the enzymes be cooked to 145 degrees Fahrenheit with a three minute rest period.

"Within a restaurant setting this temperature is typical even of rare steaks," Hansen said.

Ajinomoto and Fibrimex said the enzymes had an unblemished food safety record and had been used in the United States for two decades.

Earlier this year, public outcry erupted over the use of ammonia-treated beef that critics called "pink slime" in ground beef.

Sales of the additive dropped as consumers became aware of the practice - despite USDA and industry expert claims that the beef was safe to eat.

Last week, Beef Products Inc, the top U.S. producer of ammonia-treated beef, said it was closing three of its four plants and laying off 650 workers as a result of the controversy.

(Editing by Paul Tait)

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