Skip to main content

How Did We Can? - New Online Exhibit Looks Back

Posted by the Food Safety Research Information Office, National Agricultural Library in Health and Safety USDA Results
Jul 29, 2016
Can All You Can graphic
USDA’s National Agricultural Library launches its latest Web exhibit “How Did We Can?” on home canning in the United States.

July is the height of summer grilling season, and throughout the month USDA is highlighting changes made to the U.S. food safety system over the course of this Administration. For an interactive look at USDA’s work to ensure your food is safe, visit the USDA Results project on and read Chapter Seven: Safer Food and Greater Consumer Confidence.

The USDA’s National Agricultural Library (NAL) recently launched its newest online exhibit, “How Did We Can?The Evolution of Home Canning Practices.” The exhibit follows the evolution of home canning in the United States and the progression of associated food safety guidelines. Canning aids in food preservation by removing microorganisms responsible for decay through heating and creating a seal to prevent recontamination. Home canning held an important role in 20th century food preservation, particularly through the two World Wars, and continues to be practiced today.

“How Did We Can?” highlights changes in home canning guidelines based on a growing understanding of bacteriology. Around the turn of the 20th century, the four most prominent canning techniques were oven, open-kettle, water bath, and pressure canning. By the end of World War II, the USDA recommended only two techniques: water bath for high-acid foods and pressure canning for low-acid foods. Those recommendations remain the same under the current USDA Complete Guide to Home Canning.

During World War I and World War II, canning was touted as being imperative to the war effort on the home front and was referred to as “a real war job” in a 1945 Office of War Information poster. Home canning peaked during World War II when over four billion cans were processed in 1943. While home canning has never since reached such a height, it continues to thrive today among home food preservation enthusiasts.

For more information on current food safety issues, visit NAL’s Food Safety Research Information Office Website.