FDA fails to find E. coli in celery-onion mix

The US Food and Drug Administration (FDA) laboratory analysis did not confirm E. coli O157:H7 in the product made by Taylor Farms Pacific which the Montana Department of Health said had preliminarily tested positive.

The agency said this might be because other bacteria could have interfered with growth, it may be present in low numbers or could have died by the time confirmatory testing was done.

Taylor Farms Pacific said the statement indicates the recall was a false alarm.

“While we apologize for any inconvenience caused by the recall, we will continue to err on the side of caution to ensure food safety,”​ it said. 

Taylor Farms said it does field testing to ensure safety before produce reaches processing plants, has a field auditing program that requires ranches to undergo a full food safety audit prior to harvest and uses a  produce washing system – "Smart Wash" -- to avoid cross-contamination.

Preliminary positive prompts recall​

Taylor Farms Pacific, of Tracy, California, recalled 71 products citing “an abundance of caution​” in late November due to the Celery and Onion Diced Blend testing positive.

Five preliminary analysis tests by the Montana Public Health Laboratory indicated the presence of E. coli O157:H7 in a product sample made by Taylor Farms Pacific and from a Montana Costco.

The preliminary test was a polymerase chain reaction (PCR) test, which is commonly used to rapidly screen for presence of the DNA of a bacteria, said the FDA.

“A “PCR positive” result indicates that the sample may have contained DNA of the bacteria in question. The confirmatory testing involves culturing to grow a living colony of bacteria from the sample, to confirm that the bacteria in question is present,” ​the agency added.

““PCR positives” may not always be confirmed because, for example, other bacteria that may be present in the sample can interfere with the growth and isolation of the bacteria in question, or the bacteria in question may be in very low numbers and hard to isolate or perhaps have died off by the time confirmation testing was done.”​

Gene Grabowski, partner at kglobal, public affairs/public relations, said lost in all the attention now being paid to food safety and foodborne illness is the fact that sometimes test results are faulty.

“Different samples, depending on how widely they vary in the time they were taken and the size of the lot being tested, can affect differences in results. In addition, samples can be affected in transit and technicians can sometimes be careless in handling them,” ​he told us. ​

“The bottom line is that the chances for false-positive and incorrect test results have always existed. But the increasingly high volume of epidemiological testing that is taking place now has heightened the chances for error. That seems to be what we’re seeing in the Montana case.”​

Made for use in Costco salad​

The celery and onion mix was made by Taylor Farms Pacific for use in Costco Rotisserie Chicken Salad. It is currently not in production. 

Of the 19 ill people, 14 reported purchasing or eating rotisserie chicken salad from Costco in the week before illness started.

The Centers for Disease Control and Prevention (CDC) said 19 illnesses had been reported from seven states​ (California (1), Colorado (4), Missouri (1), Montana (6), Utah (5), Virginia (1), and Washington (1)).

Five ill people have been hospitalized and two have developed hemolytic uremic syndrome (HUS), a type of kidney failure.

The work to identify which ingredient in the chicken salad is linked to illness is continuing with the celery and onion diced blend not being ruled out as a source. 

No additional illnesses linked have been reported to CDC since November 23.