US health authorities has told consumers 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.

Also, the FDA said Hy-Vee Inc was voluntarily recalling bakery products distributed in seven states because they contained peanut butter that could be contaminated with salmonella.

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 US states, the Centers for Disease Control and Prevention said.

Twenty-three percent of the known cases had resulted in hospitalisations 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 company at the centre of the case, Peanut Corporation of America, said it had been informed by the Food and Drug Administration 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 recalled peanut butter was sold in bulk packaging 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 is sold through retail stores, PCA said.

The items being recalled by Hy-Vee include Peanut Butter Cookies, Monster Cookies and Peanut Butter Reese's Pieces Cookies and were sold in all Hy-Vee stores in Iowa, Illinois, Missouri, Kansas, Nebraska, South Dakota and Minnesota, the FDA said in a news release.

'All items should be destroyed or returned to Hy-Vee for a full refund,' it 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. - Reuters