ABSTRACT
Food preservation by freezing is a process based on the effect of low temperatures in a range of –2 to –18°C for commercial purposes, although lower temperatures can be used. It was conceived to preserve perishable foods for long periods of storage with good quality. However, there are significant differences in the shelf life of frozen foods when the storage is carried out at –12°C (or higher temperatures) compared to at –18°C. Freezing as natural phenomenon is very old and as a transformation process is one of the conventional food preservation technologies. The invention of a freezing unit by Reece in 1867 used ammonia as the refrigerant. In 1893, a load of 60,000 tons of salmon were transported from Kamchatka to United States. Clarence Birdseye, a food researcher and trader, developed freezing plate equipment, and in 1931 this pioneer founded a company to market frozen foods.
