Why was the growth of canning in the late 1800s unsustainable?

the growth of canning in the late 1800s unsustainable because the growth of microorganisms causes food to spoil. Prior to this discovery, people knew that canning methods worked but did not understand why. This is because it was still safe to eat and there was no trace of microbial growth.

Canning was unsustainable because the process back then was labor intensive; the process was still undefined, and the materials are very primitive. The cans used were corked and sealed with lead which led it to be hazardous. During the 1860s, a glass jar with a threaded cover called a Mason Jar was used popularly for canning however, these jars were expensive and often are status symbols for the middle class.