The U.S. Food and Drug Administration says meat and milk from cloned animals' offspring may already be in the food supply. (Thomas Terry/Associated Press)

A limited amount of meat and milk from the offspring of cloned animals may already be making its way to consumers' dinner plates, U.S. authorities said Tuesday.

U.S. and Food and Drug Administration spokeswoman Siobhan DeLancey said it is "theoretically possible" offspring from clones have made their way into the food supply, but she noted it would be impossible to distinguish between products made from cloned and conventionally bred animals.

Bruce Knight, the undersecretary for marketing and regulatory programs for the U.S. Agriculture Department, also noted there are a small number of clones in existence.

"They would be a very limited number because of the very few number of clones that are out there, and relatively few of those clones are at an age where they would be parenting," Knight said, according to Reuters.

In January, the FDA said in a final risk assessment that meat and milk from cloned animals are safe to consume.

FDA researchers collected data on more than 600 U.S. cloned animals and their offspring. Scientists examined a range of considerations, including size, health, blood characteristics and behaviour of cloned animals and found that nutrient levels in meat and milk from cloned animals were comparable to traditionally bred animals.

In July, the European Union's Food Safety Authority said a limited amount of evidence showed that meat and milk from cloned cattle and pigs were safe to consume. But the EFSA also said the cloning procedure may pose health risks for animals.

Food from cloned animals is forbidden for sale in Canada.