Time and again I am asked about the safety of food preservation recipes published in cookbooks, or books authored specifically for home canning. A quick search on Amazon.com indicated 669 books on home canning alone. There are books by traditional ‘authors’ like Better Homes and Gardens, and other names new to the scene offering how-to guides, books for beginners, or books to meet a certain need, e.g. canning in small batches.
The most important aspect of home food preservation is food safety. You would like the food to look a and taste good, but more importantly, it needs to be safe for you and your family to eat. And therein lies the challenge. Proving safety is much more complicated than making food look pretty in a jar and having it taste good.
Proving safety requires an understanding of food microbiology and lots of laboratory work! It is important to understand the pH or level of acidity in each product, and if that level of acidity changes over time. This information helps us determine how a product should be processed and handled. Alongside pH, is an understanding of how heat penetrates into a jar and throughout a food product. This depends on the type of food, the jar size, and the type of processing medium (steam or boiling water). In order to ensure safety, we have to test each food in each processing medium and calculate the microbial lethality for each product (in each jar size and processing system). The math involved uses a lot of complicated formulas and relies on very tiny temperature measuring devices (thermocouples) that we put in jars at varying heights (multiple jars per canner).
For safe home canning, follow these tips:
- Always, always follow a research-tested recipe. A recipe that someone has tested in the laboratory! Trusted sources (there are only a few) include: the National Center for Home Food Preservation, the USDA Complete Guide to Home Canning, University of Wisconsin Extension, and Ball Canning (current recipes only!).
- Always, always use an up-to-date recipe. Recommendations do change. Right now we are using recipes from 1997 or newer. Just because it was approved at one point, doesn’t mean it still is.
- Keep up to date. Check each year to make sure that you are using currently recommended canning guides.
- Just because it’s published or in print, does not mean the recipe has been tested and is safe. The pictures might be pretty, but is it worth the risk to your family’s health?
As we move into the canning season, remember that our goal is Safe Preserving! Barb