Getting to the Roots of Listeria – A Practice Tip from Ms. Gloom

Dr. Doom discussed “getting to the roots” of issues to ensure the cause is eliminated in her recent article. This is the same approach that facilities need to use each and every time they have a positive finding of Listeria monocytogenes (Lm), or Listeria species (L. spp.), or Listeria-like organisms in their environment, on their food contact surfaces, or in their product.

There can be two different causes for why you had a positive test result. One is a random event – what we like to call the “random drive-by” – that likely resulted from an employee doing something out of the ordinary that resulted in a positive test. This could be, for example, that the foot foaming station was being worked on for a few minutes and an employee entered the ready-to-eat (RTE) area and, unbeknownst to anyone, the strength of the sanitizer was a zero for a few minutes and the employee entered at that time. However, you will not be able to figure this out during your investigation – you will only know that your follow-up testing is all negative and the site and surrounding area were never positive before and are not positive again.

The second cause is a specific identifiable and assignable cause for which you can take corrective actions and also identify preventive measures. This could be, for example, that you review the site on the line where the positive occurred and find that there is a hairline crack in the metal. This site tests positive again as there is no effective way to clean this area. You have this area fixed and also review all other metal areas to determine whether or not there are other hairline cracks. Additionally, you implement a preventive program of inspection to find these before they become a harborage point.

The Key to “Pulling the Roots” is in the Adequacy of the Investigation

Don’t worry about who may have made an error – worry about the “why.” If you can address “why” something happened, you have a much better chance of preventing the issue from recurring. Begin with a review of the area and all documentation from around the time of the event. This means ferreting out the handwritten notes that the maintenance guys keep in their pockets as well as all official documentation.

It also means taking the time to interview personnel in the area and remember that you are not looking for the “who,” but finding the “why.” Find out if there were new people on the line, equipment breakdowns, product issues, etc. Be sure that you do not confuse an observation with a potential cause – separate cause from effect. As you are going through these steps, be sure to think about:

  1. What could have caused the issue?
  2. What will “fix” the issue temporarily?
  3. What will “fix” the issue permanently?
  4. How widespread is the issue – are other similar areas/equipment also affected?

Questions to determine “why” something occurred include:

  1. Did you fail to provide adequate training on the proper way to do something and why it had to be done that way?
  2. Was there an issue of understanding because of a language barrier?
  3. Are there other incentives that support doing it the wrong way such as financial incentives?

Listeria Investigation

When trying to determine why you have a positive result(s), you should include a review of past results. These should be reviewed to determine whether any positives have occurred and whether or not there is a trending upwards that could indicate a potential niche exists. This means mapping out the findings and dates of those findings. Many times looking at the actual map can lead to a different “view” of the findings than just a list of the locations. You may find it useful to be doing this while taking the additional investigative swabs as you dissemble equipment and look for issues. Remember that bacteria needs food and water to grow and survive so sampling areas with odors or debris makes the most sense.

The other point to remember is to follow the flow of the product and physical movement in the area. Bacteria doesn’t run or jump or swim – we (or something) have to move them. Stand in the area and see how things in that area move. How are people and equipment moving? How does the product move as it enters the line and exits? Where does the water start that is flowing to the drain? This is an important point as many investigations seem to begin and end for a positive in the drain – with the drain! Unfortunately, those investigations fail to consider what sources are running into the drain.

There is no immaculate conception that I am aware of involving Listeria – something or someone had to bring it into the area and then it “flowed” to the drain for the drain to be positive. Granted there are drains that can easily become a niche – but it had to get there first for this to occur. Look at flow to the drain and where Listeria could have been moved from when investigating positives near or in the drain. There are still many drains that are not cleanable and that you must understand will become a niche – especially down into the traps and water – and why you never want them to overflow. We will discuss drains further in an upcoming post.

Tell the Story

“If you didn’t document it, it didn’t happen.” This is true of an adequate investigation as well. Document in detail your investigation. This should be a diary of what you looked at, who you talked to, and what you did from the time you were notified of the positive result. Keep copies of the documents you reviewed for your story – not the originals as they likely belong somewhere else! Detail what you looked at or didn’t and why. Your investigation document should be sufficiently detailed so that a person with a general understanding of your process can understand, without being on site or talking to you, what happened, what you did to determine the root cause, why you took the corrective and preventive measures you did, and how you verified these took care of the issue. This is particularly important as you may have to provide your investigation report to a regulatory inspector or someone else further up the regulatory chain-of-command and they will have to understand what actions you took and why you took them without ever having taken a step in your plant.

We will continue to discuss Listeria investigation and adequate corrective and preventive measures in future blogs.

About “Ms. Gloom”

In the attorney ranks at OFW Law, there is only one who would raise a hand if all were asked if they had any “hands-on” experience in the operation of a Townsend “Frank-O-Matic” hotdog maker, producing bean sprouts for use in egg rolls or in managing a food facility sanitation crew. In fact, there are probably no attorneys out there who could raise their hands except Jolyda Swaim.

Prior to law school and OFW Law, Ms. Swaim spent years in the food industry, beginning as a microbiologist and Quality Assurance technician. In these years, she had direct charge of quality assurance, production, sanitation and consumer affair departments at various companies producing products from pickles, sauerkraut and barbeque sauce, to various meat and poultry products, to frozen entrees, egg rolls and pizza to spices and spice blends. Her last position at Sara Lee as Director of Food Safety had her auditing its facilities in the United States and Mexico to ensure facilities producing ready-to-eat products were following best practices in sanitation and product handling.

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