From the beginning, when I was learning I would read about what you can and can't do when canning. Eventually, I got to the point where I wanted to see what was actually said by the oft attributed USDA. I read these guides thoroughly & that is how I decided what I felt was safe for my family. That is what I always encourage people to do, read and determine for yourself.
Plus, it was the source of a lot of nifty pictures and charts you see.
There are seven free guides available for downloading and printing. It is a great resource to have on hand.
If you want to buy a printed version, they are available from Purdue EDU Education Store for $14.40