Listeria monocytogenes. The health authorities therefore recommend keeping the coldest part of the refrigerator between 0 and 4°C, but also ensuring its maintenance. The error sometimes lies in an everyday action that we easily put off: cleaning the refrigerator. However, a study published in 2026 in LWT – Food Science and Technology shows that the frequency of cleaning is an important factor associated with the quantity and diversity of bacteria present in domestic refrigerators. The researchers analyzed 45 devices and found bacteria of the genera
Acinetobacter, Pseudomonas And
Staphylococcus. Devices cleaned less frequently had higher bacterial loads.
Dirty fridge: a breeding ground for bacteria
Cold slows the growth of many microorganisms, but it does not eliminate them. Certain so-called psychrotrophic bacteria can continue to grow at low temperatures. ANSES and the Ministry of Agriculture point out in particular that Listeria monocytogenes resists cold and can multiply under certain conditions.
Added to this are food scraps, leaking packaging, damaged vegetables and even liquids leaking into the bins. A soiled surface can then become a source of contamination for other foods. This is particularly problematic when raw foods are mixed with ready-to-eat products.
A study carried out in Japan on 100 domestic refrigerators had already highlighted an association between microbial contamination and the frequency or method of cleaning.
The researchers notably found coliforms,
E.coli And
Staphylococcus aureus in some devices.
How often should you clean your fridge?
On this point, the recommendations must be distinguished.
The Department of Agriculture recommends cleaning and disinfecting the refrigerator monthly. Another page from the ministry advises washing the refrigerator once or twice a month with soapy water, then rinsing it with bleach.
But you should definitely not wait for monthly cleaning when food has leaked or dirt appears. The ministry recommends cleaning up any spilled food immediately and thoroughly washing the interior of the appliance.
Stricter hygiene recommendations even provide for weekly maintenance of surfaces, joints, shelves and shelves, with cleaning then disinfection.
In other words: complete cleaning at least once a month, and without waiting as soon as dirt appears, is a simple rule to remember at home.
Should you disinfect your fridge with bleach?
Yes, the ministry’s recommendations mention the use of bleach to regularly disinfect the refrigerator.
But be careful with the method. It’s not enough to wipe down a cloth soaked in bleach and immediately put the food back. After cleaning and disinfection, surfaces should be rinsed with clean water and then dried thoroughly.
The ministry insists in particular on rinsing and drying in order to avoid leaving a disinfectant product in contact with food.
If you use a sponge or cloth, it is best that it is clean and dedicated to this task. The ANSES recommendations also point out that bleach should never be mixed with an acidic product or heated, due to the risk of releasing toxic chlorine gas.
Frost should also alert you
If a significant layer of frost invades your appliance, it is time to check its operation and, in the case of a freezer, to defrost.
The ministry reminds that frost gradually reduces the efficiency of the freezer and makes it difficult to maintain the recommended temperature of -18°C. He recommends defrosting the freezer at least once a year.
For the refrigerator, an abnormal accumulation of frost can also be a sign of a problem with its operation, sealing or use. It is then useful to check in particular the closure of the door and the condition of the seal.
Also check the seals and the door closure
A refrigerator can be perfectly clean but store food poorly if the temperature is not properly maintained.
The door seals must therefore be checked regularly: if they are damaged or if the door closes poorly, hot air can enter and disrupt the interior temperature. The ministry’s technical documents also identify defective door seals and insulation defects among the factors likely to disrupt the operation of refrigeration installations.
Same principle for openings: avoid opening the door too often or leaving it open unnecessarily. Food hygiene recommendations recommend limiting openings in order to reduce cold loss.
The right temperature remains essential
Cleaning your fridge obviously does not exempt you from monitoring your temperature. In the coldest part, it must be maintained between 0 and 4°C. The ministry also recommends using a thermometer to check that this temperature is being respected.
This precaution is particularly important for the most sensitive foods. Cold greatly slows down the development of many micro-organisms, but it does not destroy them. Listeria monocytogenesfor example, can withstand cold and continue to multiply under certain conditions.
How to clean your refrigerator correctly?
For a complete cleaning, it is better to proceed methodically:
- Empty the refrigerator and store foods sensitive to cold during the operation;
- Remove the shelves, bins and accessories;
- Clean the surfaces, walls, shelves, bins and joints;
- Immediately clean any spills or food residue as soon as they appear;
- Disinfect according to the recommendations of the product used;
- Rinse with clean water after using a disinfectant requiring rinsing;
- Allow to dry thoroughly before putting the food back in;
- Check the refrigerator temperature;
- Place raw foods and ready-to-eat foods separately.
And above all, do not neglect door seals and handles, which are handled very frequently and can accumulate dirt.
HAS
Marmiton
“This mistake that we (almost all) make with our fridge actually promotes the development of bacteria”