Why food in the refrigerator does not spoil: 7 scientific reasons

The refrigerator is one of the greatest inventions of mankind, which has radically changed our diet and lifestyle. A hundred years ago, people were forced to prepare food for the winter by salting, smoking or drying, and fresh meat or milk was stored for several hours at most. Today, we can safely put chicken in the refrigerator for a week, and yogurt for a month, without worrying about their spoilage. But how exactly does this “magic box” work? Why bacteria stop multiplyingdo chemical reactions slow down?

In fact, there is no magic here - only physics, biology and well-chosen engineering solutions. The refrigerator does not kill germs (this is the task of the freezer), but only creates conditions in which they go into hibernation. Let's figure out exactly what processes protect your products from spoilage, why the optimal storage temperature for meat and dairy products differs, and what happens if the refrigerator suddenly stops working.

Spoiler: it’s not just about the cold. Humidity, air circulation and even packaging material play a key role. And modern technologies like No Frost or freshness zones add even more nuances. If you have ever wondered why eggs in the store are at room temperature, but at home they are usually stored in the refrigerator, the answers will be found below.

1. Low temperature: the main inhibitor for bacteria

The main reason why food spoils is activity of microorganisms: bacteria, molds and yeast. These tiny creatures feed on organic substances (proteins, carbohydrates, fats) and in the process of life they emit toxins, gases and unpleasant odors. However, all of them are cold-loving (psychrophilic) or mesophilic organisms that actively reproduce only in a certain temperature range.

At temperature from +4°C to +60°C most bacteria feel comfortable. But as soon as you drop below +4°C, their metabolism slows down sharply. For example:

• 🦠 Salmonella stops reproducing at +7°C, and at +4°C goes into hibernation.
• 🍄 Molds slow down growth at +5°C, but do not die
• 🧀 Lactic acid bacteria (responsible for souring milk) practically stop at +3°C

That is why optimal temperature in the refrigerator is +2…+5°C. At this temperature, bacteria do not die, but their population does not increase, which means that food remains fresh longer. However, there is a nuance: some microbes (for example Listeria monocytogenes) can multiply even at +1°C. Therefore raw meat and fish it is recommended to store in the coldest zones - on the lower shelves of the freezer.

Interesting fact: in freezer compartment (when −18°C and below) the bacteria do not die, but only fall into suspended animation. As soon as food is defrosted, microbes “wake up” and continue to spoil the food. Therefore, defrosted food needs to be cooked as quickly as possible!

2. Humidity: why vegetables don’t wilt and bread doesn’t go stale

Temperature is not the only factor affecting the safety of food. No less important air humidity. In the refrigerator it is maintained at 50–70%, and this is no coincidence:

• 🥬 For vegetables and fruits high humidity (60–70%) prevents water loss through evaporation. Without it, salad or cucumbers will become flabby within a day.
• 🍞 For bread and baked goods, on the contrary, you need low humidity (up to 50%), otherwise they will become damp and covered with mold.
• 🧀 Cheeses require average humidity (55–65%), otherwise they will either dry out or “fog up” and become covered with mucus.

Modern refrigerators solve this problem with the help of zoning: different compartments support different microclimate For example:

• 🥕 Vegetable box —high humidity (up to 90%) and temperature +5...+7°C
• 🥩 Freshness zone (if any)—humidity 50–60% and temperature about 0°C
• 🥛 Door —the warmest zone (+6...+10°C), suitable for sauces and drinks

If your refrigerator is not equipped with automatic humidity control, you can use simple life hacks:

• 💧 Place a damp napkin in the drawer with vegetables
• 📦 Store the bread in a paper bag (absorbs excess moisture)
• 🧊 For cheeses, a container with a lid and a piece of sugar (absorbs moisture) is suitable.

What happens if the humidity is too high?

When the humidity is above 80%, condensation appears on the products, which accelerates the growth of mold. This is especially dangerous for meat and sausages - they can “sour” in 2-3 days.

3. Tightness and air circulation: why odors don’t mix

Have you noticed that in old refrigerators fish “smells” like carrots, and cheese smells like sausage? In modern models, this problem is solved thanks to two technologies:

1. Sealed containers (like Fresh Box y Samsung or VitaFresh y Bosch) with separate air circulation.
2. Filtration systems (for example, carbon filters or plasma purifiers Panasonic).

But even without advanced functions, you can minimize the mixing of odors:

• 🥩 Store raw meat and fish in vacuum bags or airtight containers
• 🧀 Wrap cheeses in parchment paper (it allows air to pass through, but retains odors)
• 🍎 Keep fruits with a strong aroma (apples, bananas) in a separate drawer

By the way, air circulation is important not only for odors, but also for uniform cooling. In refrigerators with a No Frost system, fans constantly circulate cold air, preventing the formation of "warm zones". data-i="137">or drip system (for example, at Atlant or Indesit) cooling occurs due to natural convection - cold air goes down and warm air rises up.

4. Chemical processes: why fats do not go rancid and vitamins are not destroyed

Food spoilage is not only the work of bacteria, but also oxidative reactions. For example:

• 🥑 Fats (in oil, nuts, meat) are oxidized under the influence of oxygen and light, which causes a bitter taste (“rancidity”).
• 🍊 Vitamin C is destroyed when contact with air and light.
• 🥦 Chlorophyll in green vegetables under the influence of light turns into pheophytin (they turn yellow).

The refrigerator slows down these processes due to:

1. Low temperature —chemical reactions at +4°C proceed 2-3 times slower than at +20°C.
2. Lack of light —photo-oxidation does not occur in a closed space (for example, milk does not turn yellow).
3. Limited access to oxygen —in sealed containers, fat oxidation slows down by 5–10 times.

That is why vegetable oil in a bottle on a shelf it spoils in 1-2 months, and in the refrigerator in a dark glass bottle it remains fresh for six months. The same applies to nuts, seeds and even chocolate - it is better to store them in a cool place to avoid the appearance of a white coating (this is not mold, but fat that has come to the surface).

5. Technologies that prolong freshness: from No Frost to ionic freshness

Modern refrigerators are equipped with functions that not only cool, but also actively fight bacteria, mold and unpleasant odors. Here are the most effective of them:

1. No Frost system

• ❄️ Eliminates the formation of frost due to constant air circulation.
• 🦠 Prevents the accumulation of moisture where microbes could multiply.
• ⚠️ Minus: products can dry out faster (need containers).

2. Freshness zone (0°C)

• 🥩 Ideal for meat, fish, cheeses - the temperature is close to freezing, but without the formation of ice.
• 🍣 In such zones (for example, BioFresh y Liebherr) products are stored in 2–3 times longer.

3. Antibacterial coatings

• 🧼 The inner walls of some refrigerators (for example, Hitachi or Sharp) are coated with silver ions or other metals that inhibit the growth of bacteria.
• 🦠 Efficiency: up to 99% of germs die within 24 hours.

4. Plasma and carbon filters

• 🌬️ Carbon filters (for example, in Samsung) absorb odors.
• ⚡ Plasma purifiers (Panasonic) decompose odor molecules and bacteria under the influence electrical discharge.

5. UV lamps

• 💡 Some premium models (for example, Hisense) are equipped with UV lamps that turn on when the door is closed and disinfect the air.

Fresh zone (0°C)|No Frost system|Antibacterial coating|Filter for cleaning air|UV lamp (optional)-->

6. What happens if the refrigerator turns off?

Even the most reliable refrigerator can suddenly turn off - due to a power surge, breakdown or planned power outage. What will happen to the products then?

First 2-4 hours:

• ⏳ The temperature inside will rise to +8...+10°C.
• 🧀 Dairy products, eggs and cheeses will remain safe.
• 🥩 Raw meat and fish will begin to spoil (risk of reproduction Salmonella and E. coli).

After 6-8 hours:

• 🌡️ The temperature will reach +15°C - ideal conditions for bacteria.
• 🍗 Boiled foods (sausage, sausages, ready-made meals) can become dangerous.
• 🥛 Milk and cream will begin to sour.

After 12+ hours:

• 🚨 The temperature will be equal to room temperature - food spoils as quickly as outside refrigerator.
• 🍖 Raw meat and fish become unfit for consumption.
• 🧀 Soft cheeses (ricotta, mozzarella) will become moldy.

What to do if the power is turned off for a long time?

• 🔋 Use battery-powered cooling boxes (for example, Dometic or MobiCool).
• ❄️ Transfer the most perishable foods to the freezer (they will last longer there).
• 🧊 Wrap foods in foil or towels - this will slow down heating.

7. Myths about food storage: what really spoils food?

There are many myths around refrigerators. Let's look at the most popular ones and find out what is truth and what is fiction.

Myth 1: “Eggs should be stored in the door”

❌ Reality: The door is the warmest place in the refrigerator (up to +10°C, eggs spoil faster there). them on the middle shelf at +4...+5°C.

Myth 2: “Vacuum-packed products last forever”

❌ Reality: Vacuum slows down the oxidation and growth of bacteria, but does not kill them Raw meat in a vacuum at +4°C will last 7–10. days (instead of 3–5), but no more.

Myth 3: “The freezer kills all microbes”

❌ Reality: Bacteria go into suspended animation, but do not die when defrosted. The only way to kill germs is heat treatment (cooking, frying).

Myth 4: "Fruits and vegetables can be stored together"

❌ Reality: Some fruits (apples, bananas, avocados) emit ethylene a gas that accelerates the ripening and rotting of neighboring vegetables. Store them separately!

Myth 5: “The refrigerator needs to be defrosted once a year”

❌ Reality: In models with No Frost defrosting is not required. In drip refrigerators, it is enough to wipe the back wall once every 3-6 months.

FAQ: Answers to frequently asked questions

❓ Why does ice form in the refrigerator if it is not a freezer?

Ice appears on the back wall in refrigerators s drip system (not No Frost). This is normal: moisture from the air condenses on a cold surface and freezes. When thawing, the water flows into a special tray.

If there is too much ice, check:

• 🔌 Is the door closed correctly (the seal may be worn out)
• 🌡️ Is the temperature set too low
• 💧 Is warm air getting in (for example, if the refrigerator is next to the stove)

❓ Is it possible to store medicines in the refrigerator?

Yes, but not all. In the refrigerator (at +2...+8°C) they store:

• 💉 Insulin
• 🧴 Some vaccines and serums
• 🧴 Ointments and creams with antibiotics
• 💊 Rectal suppositories

⚠️ No store in the refrigerator:

• 💊 Tablets (they can become damp)
• 🧴 Cough syrups (may thicken)
• 💉 Vitamins in capsules

⚠️ Attention: If the instructions for the medicine do not indicate “store in the refrigerator,” keep it at room temperature.

❓ Why some products. cannot be stored in the refrigerator?

Not all products need low temperature. For example:

• 🍌 Bananas —at +4°C their skin turns black (although the flesh remains edible).
• 🍠 Sweet potatoes and potatoes —the starch in them turns into sugar, they become sweetish.
• 🍅 Tomatoes —lose their taste and become mealy.
• 🥑 Avocados —do not ripen, but rot.
• 🧅 Onions and garlic - dampen and sprout.

These products are best stored in a cool, dark place (for example, in a pantry or on the bottom shelf of a kitchen cabinet).

❓ How to defrost a refrigerator correctly?

If you have a model without No Frost, defrost it like this:

1. 🔌 Unplug the refrigerator.
2. 🧊 Take out all the food (put it in a cooler bag or wrap it in newspapers).
3. 🚿 Place a tray to collect water.
4. ⏳ Wait 4-8 hours (the ice should melt on its own, do not chip it with a knife!).
5. 🧽 Wash the internal surfaces with soda solution (1 tbsp. spoon per 1 liter water).
6. 🧻 Wipe dry and turn on the refrigerator 1-2 hours before loading food.

⚠️ Attention: Never use a hairdryer or hot water to speed up defrosting - this can damage the seal or plastic parts.

❓ Why do unpleasant odors appear in the refrigerator, even if everything is packed?

The reasons may be different:

• 🧼 Contamination of the drainage hole (condensation flows there, and if it is not cleaned, mold appears).
• 🔄 Poor air circulation (if the refrigerator is full of food).
• 🧀 Products with a strong smell (cheeses, fish) even in packaging "soak" air.
• 🦠 Bacteria on the walls or door seal.

How to eliminate the smell:

• 🧹 Wash the refrigerator with a solution of vinegar (1:1 with water).
• ☕ Place an open pack of soda or activated coal on the back shelf.
• 🍋 Wipe the walls with a slice of lemon.
• 🛒 Buy an odor absorber (for example, Fridge Fresh).