UPDATE 1-FDA issues peanut safety guidelines for foodmakers

* FDA may seize contaminated products

* High-fat foods help bacteria survive

* FDA urges buying from suppliers who demonstrate safety (Adds updated infection numbers, paragraphs 4, 6)

By Julie Steenhuysen

CHICAGO, March 10 (Reuters) - The U.S. Food and Drug Administration issued safety guidelines for companies that use peanut products on Tuesday and said it may seize products that test positive for salmonella bacteria.

While heat-sensitive, salmonella bacteria become heat-resistant in high-fat environments such as peanut butter, the FDA guidance advises.

The document provides advice directly relevant to a food poisoning outbreak that has renewed calls for a revamp of food safety protocols in the United States.

The U.S. Centers for Disease Control and Prevention government said on Tuesday 683 people in 46 states have been sickened in the outbreak linked to foods that used peanut ingredients made by the now-bankrupt Peanut Corp of America.

The outbreak continues to affect hundreds of the company's customers and has forced the recall of 3,235 products.

The CDC said illnesses are still being reported among people who ate recalled brands of peanut butter crackers.

Improperly roasted peanuts used to make peanut butter or peanut paste can harbor salmonella bacteria. When used in a product like ice cream, the bacteria would be protected in a cozy clump or swirl of fat, according to the FDA.

Baking peanut butter into cookies and crackers might not be enough to kill bacteria if the temperature is too low or is not maintained at a consistent level.

Because of this, the FDA urged food manufacturers to buy peanut products "only from suppliers with validated processes in place to adequately reduce the presence of Salmonella species."

And it urged companies to conduct scientific studies to check for salmonella in the products they make.

COMMON SENSE

Bill Marler, a Seattle-based lawyer who is representing 85 clients who got sick from eating tainted food, said the recommendations are just common sense for any manufacturer that uses outside suppliers.