A recent edition of New Scientist raised an interesting question about whether bacteria can live or even thrive at very low temperatures, particularly bacteria that can live inside a refrigerator. With the majority of bacteria, cold temperatures – such as the temperature inside a refrigerator – slow the metabolism of bacteria and prevent them from reproducing.
Unlike most other types of bacteria, Listeria monocytogenes, a bacterium responsible for an estimated 450 cases of food poisoning every year, can survive and often multiply to harmful levels in the fridge – even if food is stored properly. Although it may be relatively rare, around a third of cases end in death.
This is why sticking to ‘use by’ dates is important. You’ll find them present on labels for foods that are likely to go off quickly, particularly chilled food such as paté (including vegetable paté), soft mould-ripened cheeses such as Camembert, Brie and Stilton, and smoked fish. Once you open these foods they can go off quickly. Even if it looks and smells fine, consuming it after the ‘use by’ date could put your health at risk.
Certain groups of people are more at risk of listeria infection, including pregnant women, those over the age of 60, people with compromised immune systems, for instance due to illness or medication, and babies less than a month old.
So, to reduce the risk of listeria infection, ensure that you have followed the storage instructions, if any are included on the food packaging. Don’t use food past its ‘use by’ date, regardless of whether the food looks or smells fine, and ensure the temperature of your refrigerator is below 5°C.