Listeria Monocytogenes

When you think about Listeria Monocytogenes which word pops up in your mind? Do you recognize the word ‘Difficult’ when you think about this bacteria? Of course it is one of the most wide-spread bacteria that give rise to food safety issues. Often companies experience many re-occurring  issues once they find themselves involved in issues with Listeria Monocytogenes. For you as the responsible person for food safety it is all too often very difficult to pinpoint where it is coming from, where it is hiding in your factory. It is needless to say that solving the issue for your company is paramount in your job and of utmost importance for the company you work for.


Recalls are the most nasty outcome of an issue with Listeria Monocytogenes. These happen on a regular basis throughout the entire food industry. Too often companies find it difficult to determine the root cause and hence area facing a continuous and increasing risk level of finding Listeria Monocytogenes in their finished products. Do you know how to make a good root cause analysis?

The reason for this is the fact that once Listeria Monocytogenes has found a nice place to hide, it usually starts multiplying and in the end does end up in food stuff, resulting at least in product going to waste and a lot of costs for the company. But as said before, the highest price to pay will be a product recall – even resulting in a bankruptcy of the company in some cases.

Most important for you is to prevent Listeria Monocytogenes in your factory. How can you best achieve this? Water is the most determining factor in the success of defeating this bacteria. It is generally known that Listeria Monocytogenes is omnipresent in the environment – it literally sits on the soles of your shoes. This is one of the mechanisms for this bacteria to enter your food factories. Usually by wet cleaning of the floors (more often even just wet floors) bacteria accumulates in drains. Removing this bacteria from drains is easily done by inserting a chlorine tab in each drain on a weekly basis. Of course preventing water on floors and more importantly even on equipment is paramount in Listeria Monocytogenes prevention. When water must be used, make sure to install gutters and pipes to guide the water in a good fashion tow drains. The result should be dry floors at all times as this will take away the biggest risk of proliferating this bacteria. The second largest of Listeria Monocytogenes source are coolers, freezers and air conditioning units as these involved water (moisture) as well. The bacteria has a tendency to site between the cooling ribs of such systems. You need to apply special cleaning chemicals such to be able to remove the bacteria effectively from these areas (see or for more info) and clean these units on a regular basis. Also, make sure that all condensate is guided properly to a drain by using gutters and pipes to ensure no condensate falls onto open product.


Maybe you would also like to read:

The 5 Most Common Places Where to Look for Listeria Monocytogenes

WHO: South Africa’s Listeria Outbreak