Low-acid and tomato foods not
canned according to the recommendations in this publication
or according to other USDA-endorsed recommendations present
a risk of botulism. If it is possible that any deviation from the
USDA-endorsed methods occurred, to prevent the risk of
botulism, low-acid and tomato foods should be boiled in a
saucepan before consuming even if you detect no signs of
spoilage. At altitudes below 1,000 ft, boil foods for 10 minutes.
Add an additional minute of boiling time for each additional
1,000 ft elevation.