In recent years, as a new type of preservative, dry ice has become popular in the food industry.

For example, the preservation of airline food, and the freezing and refrigeration of seafood such as lobsters, crabs, and shark fins in high-end hotels.

For another example, placing some dry ice in a food warehouse or train refrigerator can not only lower the temperature, but also prevent bacteria from multiplying, thereby keeping fish, meat, and fruits fresh.

Since primitive society, people have known to use ice to keep food fresh for a long time.

Today, thousands of years later, people use dry ice instead of ice cubes because dry ice has a better preservation effect. Why is this?

Dry ice To explain this problem, we must first understand the characteristics of dry ice.

As we all know, dry ice is solid carbon dioxide.

Gaseous carbon dioxide will condense into a colorless liquid under a pressure of more than 6,000 kilopascals, and then quickly solidify into dry ice under high pressure.

Normal carbon dioxide is a colorless and odorless gas that naturally exists in the air and accounts for about 0.03% of the volume of air.

Dry ice is highly volatile and sublimates into non-toxic, odorless gaseous carbon dioxide that is 600 to 800 times larger than solid volume.

Obviously, dry ice is light, its weight is about 1/18 of the same volume of water ice.

Light weight facilitates transportation.

In addition, dry ice does not leave any liquid after sublimation, which makes it cleaner than freezing with water ice and does not make food moist.

At the same time, the density of carbon dioxide generated by dry ice after sublimation is greater than that of air. Therefore, carbon dioxide gas will attach to the surface of heavy food, isolating the food from oxygen, inhibiting the growth of bacteria, slowing down its metabolism, etc., ensuring that fruits, vegetables, and seafood products are fresh and non-toxic.

Go bad.

It is worth mentioning that using dry ice to make delicious food can also create a warm and romantic atmosphere, making diners feel as if they are in a fairyland.

Nowadays, the use of dry ice to prepare delicious food has been sought after by some high-end hotels.

Although dry ice keeps food fresher much better than ice cubes, dry ice must be transported and stored with caution.

Refrigerators containing dry ice sometimes hit the refrigerator door and make an explosion sound.

The reason is that citizens put the food they bought containing dry ice to keep them fresh together with dry ice in the refrigerator.

Because the boiling point of dry ice is -78.5°C under normal pressure, dry ice will sublime when the temperature is higher than -78.5°C; and the temperature of the refrigerator when freezing is about -20°C, so a large amount of sublimated dry ice gas will accumulate at the refrigerator door (

Equivalent to 600~800 times the volume of dry ice), over time it will be squeezed and impact the refrigerator door.

Scientific research shows that dry ice is stored in a special freezer and has a shelf life of 5 to 10 days; if this period has passed, the dry ice will begin to form ice balls or even vaporize, and the use effect will be significantly reduced.

When transporting dry ice, foam boxes with thick walls and good quality should be used. The foam boxes should also be tightly buckled and sealed with sealing tape to avoid cracking.

Finally, I would like to remind everyone that although dry ice looks like ice cubes, it cannot be picked up or handled with bare hands like ordinary ice cubes.

Because dry ice can create a low temperature of -78.5°C, it can reduce the surrounding temperature to about -20°C.

Dry ice can cause frostbite to human skin tissue if it is in direct contact with the human body for a longer period of time.