Proper Canning Safety Item Number: proper-canning-safetyFresh produce is
perishable for several reasons. Because of it's high water content
there is an increased growth of undesirable microorganisms, increased
activity of food enzymes, increased reactions with oxygen, and adverse
effects from moisture loss. All of these result in the breakdown and
spoilage of food.
Canning is the process of using heat to
destroy microorganisms responsible for the spoilage of food. Also,
during this process, air is driven from the jar and a vacuum is formed.
As the jar cools, it seals preventing microorganisms from entering and
contaminating the food. Therefore, a good vacuum keeps liquid in
and air & microorganisms out.
There are two categories of food to be noted when implementing proper
safety measures for canning.
- HIGH ACID foods have a high acid content which is an
unlikely place for bacteria to thrive in. These foods have a ph of
4.5 or lower and would include produce such as apples, apricots,
berries, cherries, peaches, and tomatoes.
- LOW ACID foods have a low acid content which can be a
dangerous breeding ground for bacteria. These foods have a ph of
4.6 or higher and would include produce such as asparagus, beans,
beets, carrots, corn, potatoes, pumpkin, squash, and sweet potatoes.
The USDA recommends pressure canning as the only safe method to
can low-acid foods such as meat, poultry, seafood, and vegetables.
Improper canning can result in the presence of Botulism, a deadly poison
caused by a toxin from the growth of spores from the bacteria,
Clostridium Botulinum. It takes a specific amount of heat, for a
specific amount of time to kill certain bacteria. This CANNOT be
achieved by water bath canning.
This however, should not scare away the beginning canner. After
following the proper guidelines below, you will be well aware of proper
processing and indicators of danger. And as always, the final step for
the safety of home-canned low-acid foods and tomatoes is to boil them
for 10 minutes after opening them. Add an additional minute for every
1,000 ft. of elevation above sea level.