I have pressure-canned vegetables for many years but always boil them for 10 minutes before consuming them. Has this rule changed?
— Darlene E., via email
First off, you're meeting the most important criteria for canning vegetables and other low-acid foods by using a pressure canner. If you're processing canned goods with timetables endorsed by the U.S. Department of Agriculture (often reiterated by state universities' extension services), they should be safe to eat.
The extra boiling time you mention is a safeguard for foods not canned according to USDA recommendations AND that show no signs of spoilage. Add one minute to the 10-minute rule for each 1,000-foot gain in elevation above 1,000 feet.
Savvy food preservers such as you know there is no remedy for canned goods that display signs of microbiological spoilage, namely botulinal toxin. The only safe way to dispose of spoiled, low-acid foods is by boiling jars with contents and lids for 30 minutes before cooling and discarding, according to Oregon State University Extension.
"You just don't know where it's going to end up along the way," says Michele Pryse, president of Extension Family Food Education Volunteers in Jackson County.
Signs of spoilage include: lids that curve outward or yield to pressure, leakage from the lid, rubber ring or elsewhere, an outrush of air or spurt of liquid upon opening, an "off" odor and any change in normal texture or appearance. Smell contents immediately after opening a jar but NEVER taste questionable foods.
And don't even consider putting spoiled items in the compost, garbage disposal, down the toilet or giving them to pets or livestock.
"No to all of the above," says Pryse.