Canning is an art passed down from our ancestors that has died out in the recent past, but with the economy, it is becoming more popular.
Since our mothers and grand mothers were canning, there has been a lot of research and progress made. We now know more about the bacterial changes that can occur in food that was not processed correctly. What worked (didn't kill any one) for our mother's is not necessary the way things should be done today.
When I first learned to can jellies and jams, you just cooked them according to the recipe and put them into your sterilized jars and waited for them to seal. Now we know that bacteria can grow in that jar and you might not even know it. It is now suggested that you water bath the jelly. Also, we always stored our canned goods with the ring on the jars, now it is not good to store the jars with the rings on. The reasons for this are, you can see the top of the food to see if mold is growing on it and if a lid is loose it is easier to tell.
Some things can now be frozen with little to no processing; strawberries spaced out on a cookie sheet until frozen and then put into a freezer bag, tomatoes can be washed a placed in a freezer bag, and there are others that I can't think of now take very little processing.
When you follow canning recipes, check with your local extension office to see if there are new ways to process the recipe.
I love to collect cookbooks and books on canning, but those old ways of processing should be looked at carefully. When you find an old canning recipe that you would like to try, check with your local extension office (most have a website that you can look these things up on) to see if the processing suggested in that recipe is still the way to go.
I'll be the first to say "That's not how my mama did it!" but that doesn't mean that we should not always be searching for safer ways to do things. Mama knew best, but times have changed and now we know more.
Plan your gardens well, so you'll have plenty of fun canning this year.