Botulism is one of the most life-threatening bacteria in canned foods. Botulism toxin is mostly found in home-canned foods. The canned foods you buy from the store, for the most part, are canned under stringent guidelines and proper temperatures. This bacteria forms the spores that create toxins only in the absence of oxygen. These are mostly found in low-acid foods.
Enzymatic spoilage is the natural deterioration of foods.
Enzymes, for example, are what make tomato's get ripe after picking. The enzymes keep working and eventually rot the tomato. These enzymes are relatively harmless and for the most part, their action can be slowed with cool temperatures. It's easy to make mistakes when preparing for the future. There are so many things to think about.