The U.S. Department of Agriculture yesterday asked U.S. farmers to keep their cloned animals off the market indefinitely even as Food and Drug Administration officials announced that food from cloned livestock is safe to eat. Bruce I. Knight, the USDA's undersecretary for marketing and regulatory programs, requested an ongoing voluntary moratorium" to buy time for "an acceptance process" that Knight said consumers in the United States and abroad will need, "given the emotional nature of this issue." Yet even as the two agencies sought a unified message -- that food from clones is safe for people but perhaps dangerous to U.S. markets and trade relations -- evidence surfaced suggesting that Americans and others are probably already eating meat from the offspring of clones. Executives from the nation's major cattle cloning companies conceded yesterday that they have not been able to keep track of how many offspring of clones have entered the food supply, despite a years-old request by the FDA to keep them off the market pending completion of the agency's safety report. At least one Kansas cattle producer also disclosed yesterday that he has openly sold semen from prize-winning clones to many U.S. meat producers in the past few years, and that he is certain he is not alone. "This is a fairy tale that this technology is not being used and is not already in the food chain," said Donald Coover, a Galesburg cattleman and veterinarian who has a specialty cattle semen business. "Anyone who tells you otherwise either doesn't know what they're talking about, or they're not being honest." Last year, [only] 22 percent of Americans who responded to a major survey said they had a favorable impression of food from clones.