Is Listeria Contamination More Persistent Than We Thought?

Posted in Food Safety Education

Seemingly, the numbers of recalls being caused by Listeria Monocytogenes concerns is increasing.  Over the last 24 months, for example, we have witnessed a lengthy series of food product recalls involving large amounts of products being contaminated at very low levels over long periods of time.

In the most recent example,  a major food company was forced to announce the recall of 372,684 pounds of hot dog and corn dog products because of Listeria concerns.  Although the company stated that no products had tested positive, the recall was announced as a precautionary measure because of potential Listeria concerns in the environment.  This is simply another costly example in a growing list of crises Listeria has created for food companies.

As I study the recent recalls involving large amounts of product produced over large amounts of time, I wonder if our understanding of how Listeria behaves in the processing environment is being proven wrong.  I can’t tell you, for instance, how many times I have heard colleagues say (and, I have proudly repeated it myself) that “we expect to find Listeria in the environment,” and that “if we don’t get any positives, we’re doing something wrong.”

But, what does that really mean to “expect to find Listeria in the environment?”  In my view, it means we are resigning ourselves to what appears to be an inescapable fact, and thus tolerating its existence.

We should not condition ourselves to expect and thus tolerate even sporadic findings of Listeria.  According to FDA, in the most recent cases, Blue Bell and other sophisticated food companies expected to find, and were finding, Listeria in their environments.  In Blue Bell’s case, Listeria that appeared to be controlled was intermittently contaminating products produced over a 5-year period.  In Dole’s case, packaged salads produced over a 6-month period were being unknowingly contaminated with a strain of Listeria that caused an outbreak and led to the March 2016 closure of its Springfield, Ohio facility.

In April 2016, in the case of CRF Frozen Foods, environmental Listeria concerns caused the company to recall all products processed and sold during the preceding two years.

In May 2016, SunOpta announced the recall of sunflower kernels because of Listeria contamination.  Because a subsequent investigation demonstrated that Listeria was present in the environment, the facility temporarily closed and, in June 2016, recalled all kernels that had been processed and sold the previous year.  In the most recent case involving hot dogs, the recall involved only four-days of production, but the root cause was likely the same.

In each of these examples, the companies involved likely “expected” to find Listeria in the environment.  I also embraced this sediment, but as I now watch company after company month after month suffer crushing recalls (some of which have caused outbreaks), I am challenging myself to disagree.

In my view, based upon each of these more recent examples, we need to change drastically the way we think:  if we truly “expect” to find Listeria in the environment, it means that we are not adequately controlling for it.  And, if we are not controlling for it, what gets into our drain can get into our foods.

I have many clients producing high-risk foods that have shared similar attitudes and suffered similar recalls.  Under the veil of the attorney-client privilege, we tested aggressively, identified all sources of contamination, and then designed cost-effective interventions to beat the Listeria away and eliminate it from the environment.  We now test extremely aggressively, not “expecting to find it,” but expecting (and having a high level of confidence) that we are keeping it out; and, that if it ever again sneaks back into our facilities, it will be immediately detected and destroyed.