canning web

by Andrea Brassfield

Summer is the time for an abundance of fresh fruit and vegetables and home canning is the “labor of love” that makes it possible to enjoy them all year long!

The key to successful canning is to understand the acidity and spoilage factor of the food you wish to can, as well as the acceptable canning methods to process those foods.  Canning interrupts the natural spoilage cycle so food can be preserved safely.

The four basic agents of food spoilage are enzymes, mold, yeast and bacteria.  The first three are destroyed at temperatures below 212 degrees Fahrenheit.  However, bacteria are not as easily destroyed.  The spore produced by the bacterium Clostridium botulinum is not destroyed at 212 degrees F.  In addition, this bacterium thrives on low acid foods in the absence of air.  Therefore, for a safe food product, low-acid foods need to be processed between 240 degrees F to 250 degrees F.  This temperature can only be achieved with a pressure canner.

It is important to always follow the processing method stated in the recipe.  You should also thoroughly examine your pressure canner to ensure it is functioning properly.

In an effort to help with canning safety, the Scotland County Extension Office is offering testing on canner lids on July 18 and July 25 from 9:00 a.m. to 4:00 p.m.  There is no registration required and the cost is $1.00 per lid.  They do mention that if your canner is not a Presto, the testing may not work.

For more information about the canner testing, you can contact Jennifer Mayfield who is the University of Missouri Extension Nutrition and Health Specialist.  You can also visit the University of Missouri Extension website at