There are some rules you must follow:
Extension offices of the universities in your state offer lots of excellent canning and preserving advice. Home canning isn’t difficult as long as you know what you’re doing.
Unfortunately, sometimes produce canned at home can make people very sick. In 2015, home canned potatoes used to make potato salad served at a church potluck in Ohio sickened 27 people with botulism. One woman died.
The extension office at the University of Connecticut offers ten rules for home canning. First, make sure that all of your equipment is in good shape. Only use canning jars that are manufactured for home canning. Jar rings should not be dented or rusty. Always buy new jar lids, since the sealing compound can disintegrate; never reuse old lids. Rubber jar rings can be reused unless they are dry or cracked.
Always follow up to date canning guidelines. Recipes that are older than 1996 should not be followed. The National Center for Home Food Preservation has good recipes and guidelines.
Then, choose the right canner. Water bath canners are best for jellies, jams, relishes, pickles, fruits, apples sauce, peaches, and tomatoes. Those products are acidic, which provide protection against Clostridium botulinum bacteria. Pressure canners should be used for all other vegetables, soups, meats fish, and some tomato products that contain low acid veggies such as celery, peppers, or onions. If you use a pressure canner, make sure the gasket is soft and pliable.
Always use high quality, just ripe produce for canning. Overripe or decayed tomatoes may have a higher pH, which is unsafe.
Always make sure that everything is clean before you start canning. Clean everything well and make sure to wash your hands.
Follow recipes to the letter. If you change an ingredient amount or type, you could make an unsafe product. Always make sure you follow processing times. Processing times for specific foods destroy the bacteria that are an issue for that specific product.
Let your jars cool naturally, right side up, for 12 hours or more before you test the seals. Cool jars away from open windows. And don’t leave screw bands on jars after they are opened. Test the seals and reprocess if necessary.
