Containing food safety with the right containers: Part 1

Glass jars are great to store food, if used properly.

Various glass canning jars.
Photo: MSU Extension/Mary Morris Donaldson.

This is part of a series detailing how containers can affect food safety. Read part two, about reusing cardboard containers, here. Read part three, about plastic containers, here.

Storing food in the right container can keep food fresh and tasty for a longer time, which can also mean less food waste. The wrong container, though, can contaminate food and cause foodborne illnesses. Michigan State University Extension recommends that only food-grade containers are used to store food. This is a three-part series that explores which containers that food should never be stored in, displayed in or baked in. This first article discusses glass jars.

Glass canning jars are great to preserve food when processed with a hot water bath, atmospheric steam canner or pressure canner. Before canning with one of these methods, examine the glass canning jars and dispose of them if there are chips and cracks. Glass canning jars that are specifically designed for freezing can be used for freezer jams, soups, and many other foods. The jars intended for freezing have a wide mouth opening to accommodate for the food expanding when frozen. Dry goods, such as rice, pasta, nuts, and other pantry items can be stored in glass canning jars, or even in cleaned glass containers from prior commercially packed food. Reusing glass containers from commercially packed food with the intent of home canning food is not recommended, though, as the glass is not tempered.

But there are also improper ways of using canning jars that are dangerous. Glass canning jars should never be used for baking, or “dry canning.” There is no such method of safely preserving food through “dry canning.” Canning jars are never to go in the oven. Baking cakes or bread in canning jars is not the same as canning for food safety. Just because a baked good is in a canning jar and the lid seals, that will not stop it from developing mold as any other baked good would.

Michigan State University Extension recommends using food-safe containers to reduce the chances of foodborne illness. For more information on keeping food safe, visit MSU Extension's Safe Food & Water website.

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