Engineering Preservation of Food Products by Refrigeration and Freezing

As heating plays important role in preservation of food products, refrigeration and freezing are also important methods for preserving different food products. Hence in heating addition of salt to process water increases its boiling point similarly in freezing addition of salt to water and ice mixture lowers its freezing point. This is basic principle used in food freezing from 1850s. Due to development in this technique value of ice production was increased great extent and researchers started mechanical production of ice. They concluded that evaporation of ether and other volatile liquids showed that ice would form on surface of containers as liquid evaporated.

Ferdinand Carre patented technique of refrigeration with ammonia. This method was finally refined by Dr. Carl Linde in Germany and David Boyle in U.S. in late 19^th century. This safe steady and reliable ammonia compression system adapted all over the world for production of ice, storage of refrigerated and frozen foods and cooling of beer from 1880s. At the same frozen meat shipments started from Australia and New Zealand. During the same period of 19^th century quantitative understanding of laws of thermodynamics was being developed. Those laws of thermodynamics provided a sound scientific basis for understanding the flow of energy fluids and work in refrigeration machinery.

As a food engineer Birdseye developed consumer size packages for the distribution of frozen foods and commercial equipment for rapidly freezing this food material. Meanwhile Birdseye developed plate freezer and belt freezer.  Due to all this development sine 1950 frozen food became a staple in the market place. Food engineers worked on different thermodynamic properties of various freezing methods including cryogenic freezing by liquid nitrogen and solid carbon dioxide.