How to eliminate bad odors from the refrigerator: remedies to remove the smell and prevent it

It has certainly happened to you that you open the refrigerator and find your nostrils asking for mercy due to a strong stench coming from the fridge itself. Obviously, the smell is not accidental: the refrigerator does not release odors directly, but due to some food now deteriorating. The stench we smell is the result of complex chemical and metabolic reactions. When foods are spoiled, in fact, they generate unpleasant odors and release volatile organic compounds (VOC) produced by bacteria that degrade them or caused by the rancidity and oxidation processes of food. VOCs, in addition to sometimes making us feel sick, can impregnate surfaces, seals and even the insulation of the refrigerator, making the odor difficult to eliminate. Generally, it is not always a walk in the park to remove them (obviously it depends on each case), but there are effective methods to get rid of this problem. In short, you need a three-step strategy: remove the source, clean thoroughlyAnd get rid of residual VOCs with materials such as activated charcoal, baking soda, ground coffee or moistened newspaper.

What causes bad odors in the refrigerator: the role of VOCs

Before seeing how to act correctly to remove bad odors from the refrigerator, we understand what happens. When food spoils, food spoilage processes take place, such as fats going rancid, or bacteria which metabolize macronutrients (proteins, lipids and carbohydrates): a variety of volatile compounds, the so-called VOCs, are thus generated (Volatile Organic Compounds). It’s one mixture of very small molecules that evaporate easily, some even at refrigerator temperatures. For example, a 2018 scientific study on smoked bacon stored in the refrigerator found that bacteria such as Lactobacillus produce alcohols, organic acids and other molecules during spoilage. These compounds are highly volatile (fall within the definition of VOC) and have very low olfactory thresholdswhich means that even in small quantities they will be perceived by our nose and “interpreted” as unpleasant odors.

In addition to being extremely “odorous”, these molecules have another characteristic: they love to “stick” to surfaces! Plastic, gaskets, porous or microporous materials can absorb them and then slowly release them over time. This is precisely where the problem arises: even when spoiled food is eliminated, VOCs can become trapped in the refrigerator. At this point, airing is no longer enough: you need a plan designed specifically to remove these smelly molecules.

The remedies to eliminate the smell from the fridge

Institutions dealing with food safety, such as the Food Safety and Inspection Service (FSIS)an agency of the United States Department of Agriculture (USDA), suggest a rather rigorous protocol divided into three phases, because only in this way is it possible eliminate or at least significantly reduce residual VOCs. Each step corresponds to a different “level” of the VOC problem.

Step 1 — Eliminate the source (VOC containment)

It is the most obvious part, but also the one that many underestimate, and it allows you to block the production of new VOCs, without however removing those already trapped:

• remove ALL food suspicious or expired;
• wash shelves, drawers and containers with hot water and detergent;
• rinse with a sanitizing solution;
• dry everything is fine and leave the door open for at least 15 minutes.

Phase 2 — Deep cleaning of surfaces (removal of absorbed VOCs)

Now we act on the more “chemical” part, actively removing the VOCs present:

• clean the inside of the fridge with warm water and baking soda (whose alkaline properties already neutralize a small part of the acidic VOCs, reducing their odor);
• review the seals are good: this is often where the VOCs are concentrated;
• ventilate Still.

Phase 3 — Adsorption of residual VOCs (the most difficult)

Here we move on to the actual science ofadsorptionand it is the most important phase when the odor is “glued” to the fridge, just like molecules resting (adsorbed) on a surface. You need to place something in the fridge that can “host” the VOCs, removing them from the fridge! Among the options, the FSIS recommends:

• activated carbon: extremely effective because its microporous structure it can host many gaseous molecules, although more difficult to find at home;
• the usual baking soda left in open trays (slow but continuous action);
• ground coffee distributed on trays, left to act for 24–48 hours;
• slightly moistened crumpled newspapersto be left in the fridge for several days.

If the smell still persists, VOCs may have infiltrated the insulation of the refrigerator: at that point a technician is needed and in more serious cases the insulation must be replaced.

Prevention is better than cleaning: tricks to avoid bad smells in the fridge

Prevention is the simplest part, but often also the most ignored, despite the fact that it is precisely prevention that avoids the subsequent “cure”. Here are the three most effective tips indicated by the FSIS:

• regularly check deadlines and signs of deterioration, immediately eliminating what is deteriorating to prevent the formation of VOCs;
• use airtight containersespecially for very odorous foods such as fermented cheeses or fish;
• Always leave an adsorbent in the fridge: a small box of bicarbonate or a small activated carbon filter intercepts VOCs before they become problematic.