WASHINGTON (AP) — Amid incidents of pets dying from dog treats, the Food and Drug Administration is proposing long-awaited rules to make pet food and animal feed safer.

The rules stem from a sweeping food safety law passed by Congress almost three years ago. Like rules proposed earlier this year for human food, they would focus on preventing contamination before it begins.

The announcement comes as the FDA says it hasn't yet determined a cause of almost 600 dog deaths believed to be linked to pet jerky treats imported from China. The agency has been trying for six years to determine what exactly is causing those illnesses.

The proposed rules would require those who sell pet food and animal feed in the United States — including importers — to follow certain sanitation practices and have detailed food safety plans. All of the manufacturers would have to put individual procedures in place to prevent their food from becoming contaminated.

The rules would also help human health by aiming to prevent foodborne illnesses in pet food that can be transferred to humans. People can become sick by handling contaminated pet food or animal feed.

Michael Taylor, FDA deputy commissioner for foods, said the rules fit together with regulations proposed in July to create better oversight over imported food, including pet foods and animal feed. The idea behind all of the food safety rules is to make businesses more responsible for the safety of the food they are selling by proving they are using good food safety practices. They might do that by documenting basic information about their suppliers' cleanliness, testing foods or acquiring food safety audits. If they fail to verify the food is safe, the FDA could stop shipments of their food.

Currently, the government does little to ensure that companies are trying to prevent food safety problems but generally waits and responds to outbreaks after they happen.

Taylor said the new rules, once they are in place, could be helpful in investigating the jerky treat deaths if those illnesses are still happening. But they still may not be able to solve the mystery because the FDA has not yet been able to determine what ingredients are causing sickness. The rules generally ask manufacturers to focus on certain hazards and do their best to prevent them.

"We are really still trying to find out what the hazard is" in the jerky illnesses, Taylor said.

The FDA said the rule could cost industry $130 million annually to comply. Smaller businesses would have more time to put the rule in place.

The agency will take comments for four months before issuing a final rule and will hold a series of public meetings to explain the proposal.

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