In my younger (much younger!) days when I was learning how to be a nurse, I began to notice that one of the tactics my instructors used to get the students to do things in a certain way was “… if you don’t, the patient will die!” This mantra was used for everything from how you washed your hands to how to you changed a dressing or gave an injection, no matter how ridiculous. Does it really matter whether you open the door to the laundry chute with your right hand or your left hand? Once I began to can food, I found similar exhortations from the experts. Each exhortation, however, was often quite different from another expert’s exhortation. So who was right?
As the years went by, canning recommendations became more and more rigid. Just take a look at a canning book from 1940 compared to one from 2010. My mother, who was born in 1917, did a fair amount of canning. I’ve written elsewhere about making jams and jellies without a water bath; today’s canning mavens tell you a water bath is essential (or the patient will die…). Yet in over 50 years of canning, my mom never used a water bath for jams and jellies, nor have I. Her jams and jellies still had good seals 30 years after her death (never mind why the stuff hadn’t been used; we’re not going there, OK?). That’s a good 75 years of combined canning experience between the two of us without one culinary disaster. So I started looking into the research (which like most research, is subject to spinning, bias and outright falsification depending on who’s doing it and who’s paying for it). Turns out there is a heck of a lot of leeway when it comes to canning.
Take the USDA recommendations. Being a government entity, the organization prefers to deal in absolutes — if they haven’t personally tested it, they don’t recommend it. Since they don’t have funding to test everything, they operate on the principle that you should only do it their way. God forbid they should indicate something is probably OK unless it’s been tested up, down and sideways. On top of that, the USDA recommendations have an extremely wide margin of safety; they’re designed for people who are ignorant, careless, not too bright, distracted or otherwise (in my husband’s inimitable prose, “Unable to pour p—s out of a boot with the instructions written on the heel.”)
What I found when I looked into the research was that food-borne illnesses tended to occur when people tried to short-cut the basics. They didn’t wash their jars thoroughly before filling them with food, or test for a seal. They didn’t check the jars for nicks and cracks, or they pressure canned for 5 minutes when the lowest recommended time was 15. They stored food under conditions in which the temperature swings were so wide that jar seals couldn’t hold up. They ate foods that looked or smelled a little off instead of tossing them. (See husband’s comment above for what sort of person we’re talking about here).
None of my comments are intended to suggest you be stupid about canning, but you don’t need to be totally anal-retentive and paranoid about it, either. If you’re an experienced canner and have been canning foods in a particular way for 40 years without problems, the odds are high that you can continue to do so. If you’re new to canning, get a good book (I think well of the classic Putting Foods By, but canning supply manufacturers Ball and Kerr both publish canning books as well). Follow the instructions, and you and your food should be fine.