Why is freezing necessary?

The biggest advantage of using refrigeration is that it prevents food from spoiling.

In Daijirin, freezing is defined as "freezing food to prevent it from spoiling."

So, why does freezing prevent food from spoiling and allows it to be preserved for a long time?

Suppresses the growth of microorganisms

Microorganisms (bacteria) are the cause of food spoilage.
Bacteria in food become active and multiply, breaking down food components and fermenting them.

Freezing prevents food from spoiling by inhibiting the activity and growth of this bacteria.

Many of the bacteria that cause food poisoning have difficulty multiplying at temperatures below 10°C, and become almost inactive at temperatures below 0°C.
Also, bacteria that are resistant to low temperatures are hardly active below -10℃.
Conversely, the temperature range between 10°C and 60°C is where bacteria are most active.
(Note: The temperature range in which bacteria becomes active varies depending on the type of bacteria.)

In addition, freezing water reduces the amount of water available to bacteria, reducing their activity.
This is the same principle as drying food to suppress bacterial activity and prevent spoilage.

Prevents food deterioration

Freezing not only prevents food from spoiling, but also prevents it from deteriorating.
Causes of food deterioration include ``oxidation of food,'' ``drying of food,'' and ``the action of enzymes in food.''
Both alter the quality of the food, stripping it of its flavor, freshness, and texture.

​The ``oxidation'' and ``drying'' of food occur more slowly at lower temperatures, and enzyme activity can also be suppressed, so freezing helps prevent food from deteriorating.

What is the appropriate temperature for freezing?

To prevent food from spoiling or deteriorating, the lower the temperature, the better.
In general, the lower the temperature, the longer the shelf life of the product.

Currently, the standard distribution temperature for frozen foods is -18℃ or below.
This temperature is set in accordance with global standards. (Codex standard)

Please note that some foods deteriorate quickly during frozen storage, so tuna, for example, is generally stored at temperatures below -40°C.