E. coli O157 in chicken salad: FDA can’t find it in celery-onion mix, but epi still counts (maybe it was an herb)

JoNel Aleccia of The Seattle Times writes that federal food-safety officials haven’t nabbed a culprit after all in an E. coli outbreak tied to Costco chicken salad that sickened 19 and led to the recall of 155,000 food products last month.

costco-rotisserie-chickenOfficials with the Food and Drug Administration said Tuesday that tests failed to identify E. coli O157: H7 from a sample of celery and onions from Taylor Farms Pacific Inc., of Tracy, Calif.

“The ongoing investigation has not identified a specific ingredient responsible for the illnesses,” the FDA wrote in a statement.

The celery-onion mixture was identified as the potential source of contamination in Costco rotisserie-chicken salad that was linked to 19 illnesses in seven states as of Nov. 23.

That was based on five preliminary tests by the Montana Department of Health, which indicated the presence of the bug in chicken-salad samples from a Montana Costco. In response, Taylor Farms voluntarily recalled multiple products that contained the celery mix on Nov. 26, followed by an expanded recall a week later.

Costco pulled the chicken salad from store shelves on Nov. 20 and stopped production.

Still, that doesn’t mean the bug wasn’t in the samples, only that later tests couldn’t find it, the FDA noted. The samples were analyzed with a rapid test to screen for bacteria. But later analysis may have failed to find the germ because other bacteria could have grown, too; there were too few of the bacteria in question to detect; they may have been hard to isolate; or they could have died off over time.

“This does not let celery off the hook,” said Craig Wilson, Costco’s vice president of food safety and quality assurance.

The salad was composed of chicken, high-acid salad dressing and the celery/onion mix. Only the vegetables have been known to be associated with E. coli outbreaks, Wilson noted.

The U.S. Centers for Disease Control said the ongoing investigation is working to identify which specific ingredient in the chicken salad is linked to illness. The celery and onion diced blend has not been ruled out as a source of the outbreak. Updates will be provided when more information is available.