The invention of the refrigerator allowed longer duration of food storage. By cooling the bacteria, already present on the food, slowed the reproduction rate of said bacteria. This is revolutionary now humans can pack, ship, and store food for long amounts of time.
A refrigerator can be defined as a electrical appliance that uses a continuous process of liquefying gases. In 1876 Carl Von Linde creates an early model of the modern fridge. This model uses methyl ether witch is harmful if absorbed or inhaled; this causes Linde to change the chemicals used to ammonia witch is also toxic to consumers.
In 1894 The Linde Technique was developed by using a large amount of air and compressing it to crate a liquid , this cause the air to be cooled, this was a much safer method than the harmful chemicals used before. This method was first used in a air cooled refrigerator produced by Electrolux in 1931.
The refrigerator is such a necessity that by 1920 there are more than 200 models available for consumer use. In 1955 80% of American homes have at least one refrigerator. And in 2005 a consumer refrigerator can be found in 99.5% of homes in America.