(CNN) -- Federal officials are urging consumers to put off eating foods that contain peanut butter until assurances are made that the foods do not contain products manufactured by the Peanut Corp. of America, some of which were found to contain salmonella.

A salmonella outbreak has sickened almost 500 people and killed at least six.

Food and Drug Administration officials said Saturday that peanut butter and peanut paste made from ground roasted peanuts, manufactured in Peanut Corp.'s Blakely, Georgia, plant were found to contain the bacteria, although a direct link to the strain that has now sickened 474 people in 43 states has not been found.

Six deaths may have been connected to this salmonella outbreak.

Peanut Corp. announced an expanded recall of peanut butter and peanut paste produced from its Georgia plant Friday night. Peanut Corp. doesn't directly supply to supermarkets, so brand-name peanut butters are not expected to be affected, according to the Centers for Disease Control and Prevention.

Instead, Peanut Corp. sells produce in bulk. The peanut butter is sold in containers from 5 to 1,700 pounds. Peanut paste is sold in sizes from 35-pound containers to tankers.

The peanut paste is used in the manufacturing of cakes, candies, crackers, cookies and ice cream, FDA officials say.

Minnesota and Connecticut health officials have confirmed salmonella Typhimurium linked to this outbreak in bulk containers found in institutions such as prisons, schools and nursing homes.

The FDA is urging companies that make these foods to check whether they use peanut butter or paste produced by the company. The recalled peanut butter was manufactured on or after August 8, 2008; the peanut paste was produced on or after September 26, 2008.

The administration is urging companies to notify consumers if the products they manufacture may contain peanut products from Peanut Corp. It is also urging companies whose products do not contain Peanut Corp. peanut butter or paste to make that information available to the public.

The Kellogg Co. announced a voluntary recall of 16 products, including Keebler and Famous Amos peanut butter cookies, because they contain peanut butter that could be connected to Peanut Corp.

Health Library Salmonella infection

The FDA does not have the authority to order a recall of products. It has to rely on companies doing so voluntarily. Congress would have to pass a law to give the FDA such power

Peanut Corp. products are also distributed by King Nut Co., which voluntarily recalled its products a week ago.

"The majority of products [like cookies, crackers, ice cream] are manufactured with products that don't come from PCA," said Dr. Stephen Sundlof, the FDA's director of the Center for Food Safety and Applied Nutrition.

However, until people can be sure that the peanut cookies or crackers they have do not contain product from Peanut Corp., the FDA is asking consumers to hold off on eating them.

Sundlof said a previous outbreak linked to salmonella-contaminated peanut butter showed that the bacteria are not necessarily killed if the product is heat-treated or baked.

"It took temperatures up to 250 degrees [Fahrenheit] to kill salmonella," Sundlof said.

Even if a cookie is cooked at 350 degrees, it doesn't guarantee that the center of the food gets that hot, making it possible for some some salmonella bacteria to survive.

CNN's Miriam Falco contributed to this report.

All About Food Safety • Centers for Disease Control and Prevention • Food and Drug Administration