SOLON, Ohio — Investigators were trying to determine Monday whether an Ohio distributor's peanut butter is linked to a national salmonella outbreak.

King Nut Companies on Saturday recalled two brands of its peanut butter after an open container tested positive for salmonella bacteria.

The suburban Cleveland-based company said in a statement that it asked customers to stop distributing all peanut butter under its King Nut and Parnell's Pride brands with a lot code that begins with the numeral "8."

Federal health officials on Sunday said the company's peanut butter had not been conclusively linked to a national salmonella outbreak.

The peanut butter was distributed only through food service providers in Ohio, Michigan, North Dakota, Minnesota, Arizona, Idaho, New Hampshire, Massachusetts and Florida. It was not sold directly to consumers.

Preliminary laboratory testing found salmonella bacteria in a 5-pound container of King Nut brand creamy peanut butter, the Minnesota Department of Health said Friday.

The Minnesota tests had not linked it to the type of salmonella in the outbreak that has sickened almost 400 people in 42 states, but the department said additional results are expected early next week.

The federal Food and Drug Administration also was analyzing samples of peanut butter from King Nut and Peanut Corporation, spokeswoman Stephanie Kwisnek said Sunday. The agency has not conclusively linked the peanut butter to the strain of salmonella that has sickened people in the outbreak, she said.