Nestlé USA said Wednesday that two samples of its Toll House refrigerated cookie dough made at a Virginia factory tested positive for E. coli bacteria this week despite rigorous safety measures put in place after a recall of the product last summer.
Nestlé also said the tainted dough had not left the factory and no recall was necessary.
The company said on Wednesday that it would shut the plant in Danville, Va., for nearly two weeks while it changes its recipe and production processes. When it reopens, the company will begin using flour that has been heated to kill dangerous bacteria, including E. coli,salmonella and listeria.
Nestlé said that all cookie dough currently in stores is safe and that it was not recalling any of the product.
It said that after last summer’s recall, it began testing samples of every batch of dough for E. coli O157:H7, the toxic strain behind last year’s outbreak.
“Everything that’s in the marketplace is fine and has passed our testing,” said Roz O’Hearn, a Nestlé spokeswoman.
Nestlé issued a huge recall of the bake-at-home cookie dough in June after it was linked to an outbreak in which at least 72 people in 30 states became ill. Public health officials suspected people got sick after eating the raw dough.
The Food and Drug Administration said Wednesday it was investigating and working with Nestlé to pinpoint the source of the latest E. coli contamination.
People who consume even minuscule amounts of a toxic strain of E. coli can become severely ill. In the worst cases, it can lead to kidney failure and death. The bacteria, which is more commonly the cause of recalls of raw ground beef, can be killed by cooking.
The company said that after last year’s recall it began testing all the ingredients entering its Danville plant, which is where most of the refrigerated dough is made. It also began testing every batch of dough and holding the product in the plant until the results were known.
The two batches that tested positive this month were made on a single day last week but final testing confirming the presence of the harmful bacteria was not completed until Monday, the company said. It informed the F.D.A. of the positive tests on Monday.
Ms. O’Hearn said that the tainted cookie dough and all dough made at the plant since would be destroyed. She added that dough made the day before the tainted batches were produced would also be destroyed.
“It sounds to me that they’re really taken aback by the fact that they’ve run into the problem again,” said Carol L. Tucker-Foreman, a food safety advocate of the Consumer Federation of America. “And so they’ve decided they cannot control their supply well enough to be confident that they won’t have E. coli contamination again and they’re going to cook their flour to prevent it.”
She was not overly concerned that the company was not planning to recall the cookie dough already on store shelves.
“Given the bad publicity they have had and the quick action they have taken to change their system now that they’ve had another contamination, it sounds to me like they’ve been pretty responsible,” she said.
“I think if they thought their brand name was at risk right now they’d be out there cleaning it off the shelves.”
Nestlé repeated warnings on Wednesday that consumers should not eat raw Toll House dough and should bake the product before eating it.
It said there could be some shortages of the cookie dough in stores in coming weeks before production resumes and inventory can be replenished.