In this story:

• Recall linked to earlier illnesses
• Salmonella source a mystery
• 188 confirmed cases
• Related stories and sites

MINNEAPOLIS (CNN) -- A food company on Friday began recalling millions of pounds of cereal sold under 39 brand names because of a possible link to a salmonella outbreak in 11 states.

Minneapolis-based Malt-O-Meal Inc. said the recall involves 2 million to 3 million pounds of plain toasted oat cereals sold at grocery stores including Jewel, Lucky, Safeway, A&P, Cub, Eagle and IGA.

Other Malt-O-Meal products, including flavored toasted oat products, are not involved in the recall. No national brands from other companies are involved.

The recalled cereal was distributed in all 50 states, Malt-O-Meal officials said at a news conference in Minneapolis. They did not say how many stores are involved.

The recall includes Malt-O-Meal's brand names of Toasty-O's and Toasted Oats. All the affected products are packaged in bags and boxes and should be returned to the store where purchased, Malt-O-Meal said.

The company stressed that its recall is voluntary and precautionary because the cereals "have the potential to be contaminated."

Recall linked to earlier illnesses

Grocery stores are removing Malt-O-Meal cereals from shelves

The recall comes a day after another Malt-O-Meal product, its Millville-brand Toasted Oats cereal, was identified as the likely source of an unusual type of salmonella that has stricken almost 200 people since early April.

That product, sold only at 505 Aldi supermarkets in 16 states, has already been pulled from shelves.

The U.S. Centers for Disease Control and Prevention on Thursday said 40 people had been hospitalized, and it advised consumers not to eat the Millville brand Toasted Oats cereal until the agency's investigation is complete.

No deaths have been reported.

Dr. John Lumpkin, director of the Illinois Department of Public Health, acknowledged Thursday that cereal is an unusual source of salmonella.

Salmonella source a mystery

"We do not know at this point how the bacteria got in it," he said. Possibilities include contamination of a water pipe or something else in the manufacturing process or human contamination, he said.

CDC spokesman Tom Skinner said investigators were trying to determine how the contamination occurred, adding, "Usually the food products that cause illness are contaminated by animal feces."

Aldi spokesman Philip Whitfield said state health officials told Aldi Inc. on Sunday that the cereal might be linked to the outbreak.

Aldi, based in the Chicago suburb of Batavia, is closed on Sundays, but the next day, boxes of Millville Toasted Oats dry cereal were taken off the shelves at all company stores.

Lumpkin said the link was not definite enough to notify the public earlier.

188 confirmed cases

The CDC reported 188 confirmed cases of salmonella poisoning in Illinois, Indiana, Ohio, Missouri, New York, Pennsylvania, Michigan, Iowa, Kansas, Wisconsin and West Virginia.

But that number was expected to rise as states reported newly confirmed cases.

All of the people were sickened by an uncommon strain of the salmonella bacteria called agona. It accounts for only about 500 to 1,000 of the estimated 2 million to 4 million salmonella cases in the United States each year, the CDC said.

Like other strains, it causes food poisoning and leads to flu-like symptoms such as headache, diarrhea, vomiting and fever that can last from 24 hours to 12 days.

It is most often spread through animal products such as raw or undercooked meat, eggs, fish and poultry, but in recent years fresh fruits and vegetables have been implicated.

Illinois was the hardest-hit state, with 46 cases since April 1, including three newly confirmed ones Thursday.

The Associated Press and Medical Correspondent Elizabeth Cohen contributed to this report.