Home canning is a great way to preserve food for food storage; but a lot of people are afraid of home canning for one simple reason: botulism. This excellent post from Proverbs 31 Woman examines the nasty bacteria and provides valuable information on staying safe. Here are a few highlights from the article to help you do it the right way:
Water-Bath vs. Pressure Canning (There is a difference!)
A water bath canner is a large pot with a loose lid. In fact, you can use any large pot for water bath canning, as long as it has a lid and a rack on the bottom that prevents the jars from touching the bottom of the pan. Foods that are safe to can using a water-bath canner must have a high acidity level of 4.6 or higher. Anything below that level of acidity must be pressure canned.
A pressure canner is also a large pot, but it must be made for the specific purpose of home canning. It's lid fits tightly and has a pressure relief valve and a gauge that helps canners monitor the pressure inside the pot. It is not the same thing as a pressure cooker. (Although some pressure canners may also be used as pressure cookers, no pressure cooker can safely be used as a pressure canner.)
Why does pressure canning work with low-acid foods? Because it gets the temperature of the food up to 240 degrees F., which is much hotter than in water-bath canning. Even then, that temperature must be maintained for a certain length of time for the spores to completely die off.
The Easy Way to Prevent Botulism
Always use recipes that have been tested in a lab. Most home canners have no reliable way to test the acidity of the food they are canning, nor do they have a way to know they've cooked food long enough to kill botulism.
When we hear about home canners giving themselves or others botulism, they've always made egregious choices. For example, in 2013, a Washington man nearly died of botulism after consuming elk meat he'd processed in a pressure cooker (not a pressure canner - first problem) for a far shorter time than he should have (second problem). When the lids started coming off his jars while in his pantry, instead of throwing the meat away, he ate it (fourth problem). In 1997, an Illinois man came near death after eating home canned pickled eggs. That's right; there is no approved home canning recipe for eggs of any type. And in 2015, someone poisoned everyone at their church picnic (killing one) by serving improperly home canned potatoes. Many news reports hint that the potatoes were canned in a water bath canner, instead of a pressure canner.
Never change a canning recipe in any way, and your home canned foods will be perfectly safe.
As you become more experienced, you will find you can change the spices in recipes like stew, or create your own soup using NCHFP's guidelines. But never change what type of canner you use, or how long the processing time is, or can anything that the NCHFP says shouldn't be canned(which includes all dairy, eggs, anything with flour, and anything so dense it can't be heated through - like pureed pumpkin or very thick applesauce).
Always use approved recipes from a source like Ball or NCHFP, and you won't have to worry about poisoning your family with untested, unsafe recipes or canning methods.
Here are a few more tips to help keep you safe (and alive):
- Never store your home canned food with the rings on. Sometimes jar lids unseal. If you leave the ring on the jar, it may reseal. Bacteria will enter the jar, and you'll never know the food is contaminated. If you leave the ring off the jar, however, it will not reseal...so when you discover the open jar in your pantry, you will throw the whole thing away, rather than eat it.
- Don't stack anything (other jars, commercially canned food, etc.) on top of jars. Again, stacking things on top of jars can make lids open and reseal, just like keeping the rings on.
- Store home canned food in place where temperatures don't fluctuate and it is neither hot nor cold. (If you're comfortable, so are your jars of home canned food.)
- Pay attention when you open a jar of home canned food. If the seal isn't tight, don't eat the food in the jar.
- If you find a jar with a bulging lid, it is contaminated; don't eat it.
- If you open a jar and liquid or foam squirts out, the contents aren't safe to eat.
- Smell the food while it's still in the jar. If it smells off in any way, do not eat it.
- If there is any mold in the jar, throw it away.
- If you do suspect any home canned food is spoiled, place the jar and food in a plastic bag, seal it, and dispose of it in the trash. Wipe up any spills with diluted bleach (1/4 cup bleach to 2 cups of water, according to the CDC).
For more information on botulism, see the Centers for Disease Control and Prevention.