As wonderful as microwaves are, they are not appropriate for home canning. The purpose of canning is to destroy bacteria and prevent food-borne illness. Improperly canned foods provide an ideal environment for Clostridium botulinum bacteria to grow. There are only two approved methods for canning food at home — boiling water canning and pressure canning.
Microwaves can’t reach a high enough temperature to safely destroy bacteria. They also heat unevenly, so you can’t guarantee consistent heat to each jar during processing. As a result, cold spots could protect bacteria from being destroyed. There is also a risk of the jars exploding when removing them from the microwave due to the vigorous boil. Use safe canning practices and skip the microwave when canning.
For more information on home canning, see Quality for Keeps: Steps to Success in Home Canning.
Additional nutrition and food safety information can be found at MissouriFamilies.org.
Contributor: Karen Sherbondy, MEd, RD, LD, Extension Associate, Nutrition and Exercise Physiology, University of Missouri Extension, 816-655-6227