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Leery of Using WGS? Ignorance Is Not Bliss

After an initial recall of one batch of cheeses in early January due to a sample testing positive for Listeria, CDC and FDA reopened the investigation when new illnesses were reported and whole genome sequencing (WGS) analysis of the cotija cheese sample showed it to be the same strain of Listeria monocytogenes that is causing illnesses in a current outbreak.

Many food facilities continue to avoid the use of WGS because it is able to link pathogens across space and time, potentially linking them to an outbreak through pathogenic strains in their facility of which they were not aware. That is, however, exactly the reason you should be using WGS. Not knowing what is going on in your plant environment is more dangerous than knowing. By knowing if you have an issue, you can do something about it before it leads to an outbreak and/or is detected in an FDA inspection – for which WGS has become a standard tool. If you have tools that you choose not to use and there is an outbreak that could have been prevented, you are potentially setting yourself up for more trouble, particularly if the situation results in the involvement of the Department of Justice or other litigation related to illnesses.

Although facilities can use other sampling methods, we see WGS as a cutting-edge tool through which food businesses can stay out in front, detect issues and correct them – rather than fearing what FDA may find. Because WGS can track across space and time, it can detect resident strains in a facility, linking a current strain to one detected in a previous – or future – outbreak. Wouldn’t you rather it be you to find the pathogen and correct it, rather than FDA informing you that they did?

Take, for example, the 2015 Listeria outbreak linked to Blue Bell ice cream, in which FDA’s use of WGS connected cases since 2010 to the 2015 outbreak, causing the company to recall all product for the five-year span. As CDC’s Dr. Robert Tauxe said at the time, “the fact that it was the same strain over the last five years suggests it could have lurked somewhere in the factory the whole time.” Due to the extent of the contamination, Tauxe also stated that there could be undiagnosed cases, which the WGS testing could connect.

As a result of the outbreak, Blue Bell recalled eight million gallons of ice cream, temporarily shut down production at all its facilities, was ordered to pay $17.25 million in criminal penalties for shipments of contaminated products linked to the outbreak and paid out an additional $2.1 million to resolve civil False Claims Act allegations. Additionally, the former CEO was sentenced – just last year – to pay $100,000 for introducing adulterated food into the market. The outbreak caused 10 hospitalizations and three deaths.

The current cheese outbreak has, thus far, caused 26 known illnesses, 23 hospitalizations and 2 deaths and impacted 45 brands/retailers and a variety of foods containing the cheeses.

Given situations such as these, it makes sense for facilities to do all you can to ensure your environment is clean and detect any incoming or lurking pathogenic strains, to keep your product and consumers safe, and to keep from getting informed by FDA that they have detected something you haven’t.

A WGS match alone in a food product does not necessarily mean that food was the cause of illness in a patient with the same WGS strain. The epidemiology and food history also have to be aligned for such linkage. This is important to keep in mind when talking to CDC or regulatory agencies.

While the detection of a pathogen in your plant, even by WGS, does not necessarily mean it originated there, it may involve you in a recall if determined to be of an outbreak strain that is linked to illnesses.

There is a fear that any WGS a company does would be discovered by FDA and used as evidence against that company. In theory that may be true, but TAG has never seen that actually happen in the years since WGS has been available.  Thus, one has to look at the risk/benefit equation around the value WGS can bring, which is significant, versus the risks it brings, which are relatively minimal based on prior history.

Do you need assistance in implementing best-practice detection and/or environmental controls in your facility? TAG has extensive experience in this area, having worked with numerous companies in both risk mitigation and crisis management. Give us a call!


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