Why does food in a supermarket freezer not defrost?

Food in a supermarket freezer does not defrost because the freezer maintains a low temperature that prevents the ice crystals in the food from melting. The temperature inside a supermarket freezer is typically kept at around -18 degrees Celsius (0 degrees Fahrenheit) or below, which is cold enough to keep food frozen solid. In addition, the freezer is usually well-insulated to prevent heat from entering and causing the food to thaw.

When food is frozen, the water inside the food turns into ice crystals. These ice crystals damage the cell walls of the food, which causes the food to lose its texture and flavor. However, when food is frozen at a low enough temperature, the ice crystals are so small that they do not damage the cell walls. This is why food that is frozen quickly and stored at a low temperature retains its texture and flavor better than food that is frozen slowly or stored at a higher temperature.

The low temperature inside a supermarket freezer also helps to prevent the growth of bacteria. Bacteria cannot grow at temperatures below freezing, so food that is kept frozen is safe to eat for long periods of time.

In addition to keeping food frozen, supermarket freezers also help to keep food fresh. When food is frozen, the enzymes that cause food to spoil are slowed down. This means that food that is frozen can last for much longer than food that is not frozen.