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Feature Articles: Food, Fitness and Cooking and Produce

Summer garden produce brings bounty of food preservation questions, concerns
Cucumbers for pickling

When backyard gardens are overflowing with cucumbers, Grandma’s home-canned pickles are not far behind. Before you take the first bite of that crisp, tangy pickled cucumber, it might be wise to ask, “Is her recipe safe?”

No offense to Grandma, but it’s probably not safe. Many of the old family favorites use methods that have been deemed unsafe, said Sarah Janicek, who answers food safety questions for University of Missouri Extension’s nutrition education programs.

“People are still using really old recipes that are not reliable or safe,” Janicek said. For Janicek and other extension nutrition specialists, home canning questions are as much of a summer tradition as Grandma’s pickles. Answers to those questions focus first and foremost on ensuring that home canners know the current recommendations to prevent the possibility of food-borne illnesses and spoilage.

Common mistakes include failing to heat pickles in a boiling-water bath, and under-processing tomatoes and other items produced using recipes based on trial and error rather than good food science.

Though the U.S. Department of Agriculture — the definitive source on home food preservation — completely revamped canning recommendations in 1989, old methods still persist.

“Sometimes they (home canners) don’t realize the risk they take because up to this point they’ve managed to escape the most serious consequences, or have not understood why jars come unsealed or spoiled on the shelf,” said Cynthia Fauser, an MU extension nutrition specialist in St. Louis.

For years “cold packing” — treating vegetable-packed jars in a hot-water bath — was the favored method for green beans and tomatoes, vegetables still popular among home canners. The technique was based on pre-World War II science when microbiology was still in its infancy, Fauser said.

Food scientists now know that water-bath canning is not safe for low-acid foods, which includes vegetables, meats and vegetable-meat combinations, she said.


“CI Botulinum goes active when it’s canned,” Fauser said. “It particularly likes low-acid, air-free environments, as in canning jars with low-acid vegetables. It’s undetected by taste or smell, but one taste can produce potentially deadly stroke-like symptoms,” she said.

Janicek said, “Low-acid foods need to be pressure canned to kill the botulism spores.”

Tomatoes are borderline acidic, so safeguards include added lemon juice and increased processing times for many tomato products, Fauser said.

Tested recipes use processing times based on the specific recipe’s pH, the size of the jar, thickness of the product and even altitude. “That’s why home canners need to stick to tested recipes and follow procedures precisely,” Fauser said.

“Just because the recipe has been published in a book doesn’t mean it’s been tested. There’s no requirement for recipes to be safety tested,” Fauser said.

Fauser and Janicek advise getting the latest processing recommendations from the National Center for Home Food Preservation, the home of USDA’s and Extension’s research for home canning.

They recommend using only tested recipes from current MU Extension publications, the “USDA Complete Guide to Home Canning,” or the “Ball Blue Book.”

“I only recommend recipes from these three sources because they are based on the recommendations from the National Center for Home Food Preservation,” Fauser said.

Fauser added: “The bottom line is that you have to take the safety into your own hands when you want to be a food processor.”

Missouri residents with questions about home canning can contact the MU Extension’s Show-Me Nutrition line at 1-888-515-0016. Residents can also call their county Extension office and ask for the nutrition specialist.

MU Extension Quality for Keeps food preservation publications provide additional information. They may be viewed or ordered online at or purchased at local Extension offices.

Sources: Sarah Janicek & Cynthia Fauser, former Nutrition and Health Education Specialists, University of Missouri Extension


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Last update: Monday, July 28, 2014