This time last month the Food Safety Authority of Ireland (FSAI) issued an alert over a listeria outbreak linked to a substantial recall of hundreds of ready-to-heat meals.
Nine cases of listeriosis (the disease caused by listeria bacteria) were detected at the time, while it was confirmed that one person died with the disease.
In the weeks since there have been at least seven more listeria-related food recalls affecting products such as spinach, mixed leaves, chicken & pasta ready meals, coriander, hummus, as well as various types of cheese.
Why the sudden rise in recalls?
Each time the FSAI has issued a recall alert, it’s been keen to stress there is no evidence any of them are linked to the initial recall and the wider listeria outbreak.
However, given the scale of the initial recall in July – affecting over 200 types of ready meals produced by Ballymaguire Foods and sold in most major supermarkets under different brand names – numerous food safety experts have suggested this may have led to heightened vigilance from producers when it comes to the risk of listeria.
It’s also worth noting that in the first instance, it’s the producers themselves that are obligated to raise the alarm and alert authorities to such incidents and they carry out their own testing.
For example, producers of ready-to-eat food must test factory areas and equipment for listeria on a regular basis to pick up early signs that it may have contaminated their production processes.
They also test the finished food to verify that all the listeria control measures in their production facility are working as designed.
Based on this, it would be understandable if there were a heightened awareness around testing and reporting but food-safety officials are adamant there’s nothing to suggest a link.
Testing methods for listeria have also become more advanced in recent years, which allows for earlier and easier detection.
So the higher level of recalls shouldn’t be viewed in the context of a drop-off in safety standards, rather a more rigorous and efficient testing system.
How dangerous is listeria?
Listeriosis is an infection caused by the bacterium listeria monocytogenes, which is usually acquired by eating food contaminated with this bacterium.
It is widespread in the environment and gets into food via animals, plants, soil, and water.
On average each year, there are between 14 and 22 cases of listeriosis reported in Ireland.
But what sets listeria apart from many other harmful bacteria is the ability to survive and grow in moist, cold environments – the conditions found in pretty much every food-production factory.
Unfortunately people’s fridges also tend to be moist, cold environments and with an average temperature of around three degrees Celsius are ideal conditions for listeria to thrive in.
It can grow slowly even under refrigeration, making the bacteria especially hard to eliminate in food-processing facilities.
That’s why it’s no coincidence the relevant food recalls are related to food we mostly store in the fridge.
Anyone can become ill from eating food contaminated with listeria.
The symptoms of an infection can be flu-like, or gastrointestinal such as nausea, vomiting and diarrhoea. In rare cases, the infection can be more severe.
Some people are more vulnerable, including pregnant women, babies, and people with weakened immune systems, including the elderly.
Many people who contract listeria might not even notice any symptoms, and for many more they may feel some of the minor symptoms.
It’s the vulnerable cohorts for which it poses the highest risk.
What’s the advice for anyone concerned about the risk of listeria from contaminated food?
In the first instance consumers are advised to check their fridges and freezers for any of the implicated products and dispose of them.
The up-to-date list of products affected by recalls can be accessed on the FSAI website.
After that, the safest approach is to make sure you’re cooking food properly, in-line with manufacturers’ instructions.
Heat is what kills listeria, so ensuring any ready meals, side dishes, etc. are piping hot before consuming is recommended.
Some industry experts have also suggested changing consumer habits might be playing a role in food becoming contaminated with listeria.
We are eating an increasing number of ready-to-eat meal products, which are mostly stored in fridges.
This inevitably leads to more instances where people might eat some of a product (e.g. mashed potato, mixed vegetables, etc.) and put the rest back in the fridge for use at a later stage.
And this is where the listeria risk spikes, as the longer food sits the more opportunity the bacteria have to grow.
As already mentioned, unlike most bacteria listeria multiply slowly at normal fridge temperatures.
Open containers can also expose food to cross-contamination from other items in the fridge, while condensation can form inside open containers and create the damp environment in which listeria thrives.
If the bacteria are present anywhere in a fridge, uncovered food makes it easier for them to transfer.
Normal surface cleaning might not be enough to remove listeria, but making sure open food containers aren’t left in the fridge for extended periods is an effective way of lowering the risk.
