You put yesterday’s leftover side dishes in the refrigerator.
When you take them out today, they smell strange.
They were definitely somewhere cold, so why did this happen?
3-line summary
1. Refrigerators do not kill bacteria—they slow them down.
2. Keep refrigeration at 5°C or below, and fill it to only 70% capacity.
3. Check your refrigerator’s temperature.
It Hasn’t Stopped—It Has Just Slowed Down
It is easy to think that food becomes safe once you put it in the refrigerator. In reality, bacteria do not disappear; their rate of growth simply slows down.
Temperature determines that rate. According to Food Safety Korea standards, refrigeration should be 5°C or below, and freezing should be -18°C or below.
So if the temperature does not stay at 5°C or below, food can spoil even inside the refrigerator. “It feels cold” and “it is 5°C or below” are different things.
The Two Places Where 5°C Is Broken
The door shelves. This is where outside air reaches first whenever the door is opened and closed. In summer, indoor temperatures can approach 30°C, and that temperature difference comes straight in. That is why perishable foods should not be stored here.
Many people keep milk in the door compartment because it fits perfectly there. But milk happens to be among the foods that are sensitive to temperature.
An overfilled refrigerator. Cold air circulates inside to keep temperatures even. If it is packed with no gaps, that circulation is blocked, and somewhere inside will exceed 5°C. The Ministry of Food and Drug Safety advises filling it to only about 70% of its total capacity.
People say that a fuller freezer is better, but that should not be applied directly to the refrigerator compartment.
Which Shelf to Use
These are the food-specific storage temperatures provided by the Ministry of Food and Drug Safety.
| Food | Appropriate temperature |
|---|---|
| Seafood and chicken | 0–3°C |
| Beef and pork | 1–3°C |
| Milk and dairy products | 3–4°C |
| Vegetables | 4–7°C |
| Fruit | 7–10°C |
Temperatures vary by location even within a single refrigerator. In general, the back of the bottom shelf is the coldest, and the door area is the warmest.
So fish and meat should go deep inside, fruit and vegetables in the drawers, and items that can tolerate somewhat warmer storage—such as jam or sauces—on the door. Surprisingly many refrigerators have this order reversed.
Leftovers Are a Matter of Time
The Ministry of Food and Drug Safety advises eating cooked food within 2 hours or refrigerating it. Soup left on the table for two hours in summer has already crossed that line.
Leaving food out for a long time to cool it is no different. According to a Financial News report, it is better to divide it into shallow airtight containers. If you put an entire deep pot in the refrigerator, the center can take several hours to cool, while the refrigerator’s overall temperature rises in the meantime.
There is also a time limit after refrigeration. The Cleveland Clinic standard cited in the same report is 3–4 days refrigerated and 3–4 months frozen.
When reheating, heat it to at least 74°C for at least 1 minute. Warming only the surface until it is lukewarm is not enough.
Thawing Frozen Food Is the Most Dangerous Time
Many people take food out of the freezer, leave it on the sink, and go out. This is the method to avoid most.
The outside has already thawed and reached room temperature while the inside remains frozen. After several hours in that state, bacteria grow only on the surface. The Ministry of Food and Drug Safety advises using a microwave instead of thawing at room temperature. If you have time, thawing it slowly in the refrigerator is better.
It is also not recommended to refreeze something once thawed. Bacteria that multiplied while it thawed remain even after refreezing.
Freezing food in portions from the start reduces this concern. The Ministry of Food and Drug Safety also advises dividing a geun of meat into single-meal portions rather than freezing it all at once. If you take out only what you need, there is no need to refreeze it.
Three Things to Do Today
Put in a thermometer once. The temperature displayed by a refrigerator is the value at one point where the sensor is located. The door area and the interior may differ, and you will not know the difference until you measure it. A thermometer costing just a few thousand won will do.
Reorganize the shelves. Meat and fish inside; sauces on the door. Simply changing where things go can change how often food spoils.
Write down the date. A piece of masking tape on a food container eliminates the problem of counting 3–4 days. It is more accurate than judging by smell.
The point is not to trust the refrigerator, but to trust the temperature.
If you raised the temperature to save electricity, it is better to lower it again in summer. The cost of food that spoils and gets thrown away is greater.
References
- Financial News "Don't Store Leftover Food 'Like This'…How to Prevent Food Poisoning"
- Republic of Korea Policy Briefing I Became Curious About My Refrigerator's Storage Temperature
- Food Journal How to Handle Refrigerated and Frozen Foods at Each Distribution and Consumption Stage, as Guided by the Ministry of Food and Drug Safety
- Ministry of Food and Drug Safety How to Use Your Refrigerator Properly During Summer
The temperature standards and storage tips above refer to these sources. The storage period for a specific food varies depending on its condition and how it was cooked, so please do not eat it if anything seems off.