WASHINGTON (Reuters) - U.S. health authorities told consumers on Saturday to avoid eating products that contain peanut butter until they can determine the scope of an outbreak of salmonella food poisoning that may have contributed to six deaths.

“We urge consumers to postpone eating any products that may contain peanut butter until additional information becomes available,” Dr. Stephen Sundlof of the Food and Drug Administration’s Center for Food Safety said in a teleconference with reporters.

As of now, there is no indication that “major national name brand jars of peanut butter sold in retail stores are linked” to bulk supplies of peanut butter and peanut paste recalled for fear of possible contamination, the FDA said in a follow-up statement.

The company at the center of the matter, Peanut Corporation of America, or PCA, said it had been informed by health authorities that some samples of its products had tested positive for a salmonella strain that may have originated in a Blakely, Georgia, peanut processing plant.

The peanut butter and peanut paste recalled by PCA was used by many other manufacturers to make such products as cakes, crackers, candies, cookies and ice cream, the FDA said.

“In terms of food products which contain peanut butter, but have not yet been recalled, we urge consumers to postpone eating these products until information becomes available about whether that product may be affected,” an e-mailed statement said. “We have been advised by manufacturers that product specific information may be available within the next few days.”

The FDA is asking companies to check the records of their supply chain and determine if their ingredients came from PCA, and if so, to take “appropriate precautionary measures.”

As of Friday night, 474 people had been reported infected by a salmonella outbreak linked to peanut butter by public health authorities in 43 of the 50 U.S. states, the Centers for Disease Control and Prevention said.

Twenty-three percent of the known cases had resulted in hospitalizations and the infections may have contributed to six deaths, said Dr. Robert Tauxe, deputy director of the Centers’ division of Foodborne, Bacterial and Mycotic Diseases.

The very young, elderly and immuno-compromised were the most severely affected, he said in the teleconference. The reported illnesses began in September and 21 cases were reported on Friday.

The recalled peanut butter was sold in containers ranging in size from 5 pounds (2.3 kg) to 1,700 pounds (771 kg) and the peanut paste was sold in sizes ranging from 35-pound (16-kg) containers to tanker containers. None of the peanut butter or peanut paste being recalled so far is sold through retail stores, PCA said.

Kellogg Co said late on Friday it was recalling certain products that “have the potential to be contaminated,” including some Austin and Keebler branded peanut butter snacks and some Famous Amos and Keebler Soft Batch cookies.