h century as the refrigeration system became for efficient, controllable and even mobile. Refrigeration makes transporting fresh food and other perishables possible and makes home storage for days or weeks practical. By the end of the 20th century, 99.5 percent of U.S. households had at least one refrigerator. Many had separate freezers. People were able to simplify shopping and save money while enjoying a greater diversity and higher quality of food because of the excellent preservation technology.The main reason we have electric refrigeration today is because of the Research, Development and marketing investments of General Motors, General Electric, Kelvinator, and Westinghouse. These corporations, large at the time and some larger today, decided that the electric refrigerator offered a greater profit potential. There just was not as much money to be made in producing gas refrigerators. They devoted huge sums of money into both research and development and promotion of the electric refrigerator. New at the time, television advertisements depicted the electric refrigerator as modern, efficient, clean and safe. The smaller companies producing and marketing the gas refrigerator simply could not compete. In the 1970's, the gas refrigerator made a partial comeback as the best alternative for trailers, boats, hotels, offices, and mini-bars.The fundamental reason for having a refrigerator is to keep food cold. Cold temperatures help food stay fresh longer. The basic idea behind refrigeration is to slow down the activity of bacteria (which all food contains) so that it takes longer for the bacteria to spoil the food. For example, bacteria will spoil milk in two or three hours if the milk is left out on the kitchen counter at room temperature. However, by reducing the temperatures of the milk, it will stay fresh for a week or two. The cold temperatures inside the refrigerator decrease the activity of the bacteria that much. By ...
