Listeria, blessing or curse?

Listeria monocytogenes; no matter how small the bacterium is, it can be food producers’ worst nightmare. Because Listeria is all around us and not easy to control. The chilled fresh section in the supermarket is only getting larger, but that is precisely where Listeria feels at home. Characteristics: can survive drought and multiply considerably in a short time; even at very low temperatures. Listeria forms a major risk, babies and people with reduced resistance can get very ill or even die from it. Sounds mostly like a curse.

But where there is danger, you take measures. Specific requirements for this bacterium have been included in the European Regulation (EC) No. 2073/2005. Lots of research is being done worldwide, so that we better know how to avoid a Listeria breakout in food production companies and how to guarantee the shelf life associated with a product. What you need to do (or add to the product) to ensure that the bacterial growth stays below the norm. Producers who are innovative and at the forefront of developments bring safe products onto the market and are ahead of their competitors. To assess the risk of outgrowth, challenge tests and shelf life studies have been refined and improved. In short: a blessing.

Despite all of this acquired knowledge, the absence of Listeria monocytogenes still cannot always be guaranteed. A producer may use an intermediate limit value, but substantiating it is no easy task. This can even cause a laboratory director sleepless nights. A strong trigger for more research into better methods. With the PCR technique, we can demonstrate the presence/absence of Listeria in various sample quantities (25 grams to 1 gram) and use it to substantiate an intermediate limit value.

Pieter Vos
Director of Nutrilab