Organisms that cause food spoilage – molds, yeasts and bacteria – are always present in the air, water and soil. Enzymes that may cause undesirable changes in flavor, color and texture are present in raw fruits.
When tomatoes are canned, they are heated hot enough and long enough to destroy organisms that can make people sick in addition to spoilage organisms. This heating (or processing) also stops the action of enzymes that can spoil food quality.
Canning Tomatoes and Tomato Products
