WASHINGTON (Reuters) – Animals genetically engineered to produce drugs and healthier foods will be subjected to review to help protect consumers from any unknown risks, the U.S. Food and Drug Administration said on Thursday.

The FDA published detailed proposed guidelines that producers of genetically engineered animals would have to follow to determine if there are any risks to humans, the environment and the animals themselves.

The proposed guidelines bring the decades-old technology of genetic engineering one step closer to the consumer’s dinner table. Genetically modified cattle, pigs, fish and goats are being made for a variety of uses.

Some produce pharmaceuticals in milk or blood. Others have traits to make them resistant to diseases such as mad cow disease or to produce more healthful meat or milk.

“Many kinds of genetically engineered animals are in development, although none has yet been approved by the agency for marketing,” said FDA Deputy Commissioner Randall Lutter.

Foods produced from some bioengineered animals will not have to be labeled, FDA said. The agency is inviting public comment on its proposals and could modify them before they become final.

Consumer groups said the move was a good first step but they were disappointed that the FDA would not require all genetically modified animal food products to be labeled.

“It is incomprehensible to us that FDA does not view these animals as different from their conventional counterparts,” said Jean Halloran, director of food policy initiatives at Consumers Union.

“Consumers have a right to know if the ham, bacon or pork chops they are buying come from pigs that have been engineered with mouse genes.”

But the FDA said labeling will be required if there is a significant change in the food that makes it different from ordinary products.

Some animals have been made to produce healthier foods, such as pork with higher levels of omega-3 fatty acids. Those would need a label.

Producers will be required to describe the DNA and how it behaves in the animal, the impact of the change on the animal’s health and show the product is not different from traditional food.

The companies also will have to inform the FDA how they will keep track of the animals and dispose of them when they die. If there is a high risk, the FDA might require the animals to be sterilized to prevent them from breeding with other animals.

The FDA said it has the authority to regulate genetically engineered animals through the Federal Food, Drug and Cosmetic Act.

The measure identifies a drug as anything that changes the “structure or function” of the person or animal. In this case, an animal is genetically modified by adding a piece of DNA to introduce a desired trait.