FAQs on Preservatives

Foods can deteriorate for one or more of these reasons:

- Enzymes naturally present in the food change some component of it (by browning  bananas or softening the texture of apples);

- The oxygen in the air oxidizes some natural component making it look, smell, or taste “off”;

- Microorganisms grow and cause changes that make food either unacceptable (spoiled) or unsafe to eat. 

In general, preservatives inhibit the enzymes, stop the oxidation process, or make the environment (the food) a poor habitat for microorganisms.

By Susan Brewer, Ph.D., University of Illinois,
Department of Food Science and Human Nutrition