Canning Through the World Wars
American housewives canned more than 4 billion cans and jars of food in 1943, and nearly 3 ½ billion quarts of food in 1944. The latter represents nearly one-half of the canned vegetables and two-thirds of the canned fruits that were available for civilian consumption that year.
--Toepfer, E. W. & Reynolds, H. (1947). Advances in home canning. United States Department of Agriculture: The Yearbook of Agriculture 1943-1947. Retrieved from http://naldc.nal.usda.gov/naldc/catalog.xhtml?id=IND43894002&start=0&searchText=&searchField=&sortField=&yearFacet=1943&authorFacet=Reynolds%2C+Howard
Canning as a method of food preservation greatly increased with the advent of both World War I and World War II, spurred on by rationing and advanced techniques, along with an increased awareness of the importance of following good food safety practices.