Googled around, but I can't quite find a definitive answer, doesn't really matter but I'm curious. So maybe some of you old farts experienced canners would remember what they said when the change was made.

The U.S. changed the canning recipe recommendations for low-acid foods in 1990, requiring they be processed via a pressure cooker to achieve higher temperatures, to reduce botulism outbreaks.

Was this because we where just tightening up on recommendations -- i.e. it was always a problem, and they decided to go after home canning as one way to reduce the illnesses from it even more;

Or was it because Botulism itself had either gotten more prevalent, or had developed worse strains, and had become a problem on a scale it hadn't previously been? Similiar to how 30 years ago e-coli was not a major problem but became one with the development of nastier strains?

It seems to me the main thing that was changed was the times for canning tomato products. The reason being that the new strains of tomatoes are less acid than some of the old varieties.

I have not heard any thing about worse strains of botulism.

Here is the problem: Botulism spores that grow in anerobic conditions (like in a sealed jar) produce toxins. These toxins are deadly. The survival rate of persons poisoned by these botulism toxins is very small. It is a death sentence, not an upset stomach. You can wipe out your whole family with one bad jar of something. It is not something you want to fool around with.

The new times were the result of extensive testing to make sure that recipes are safe. For this reason I highly recommend that you use only tested and approved recipes for home canning. The Ball Blue Book recipes, and recipes obtained from your extension service are good. Grandma's recipe may be a high risk. Get the current Ball Blue Book not an old one.

Botulism spores will not grow if the acid content is high enough. For this reason, do not ever change amounts of things in a recipe that may change the acidity.

Always use a pressure canner for non acid and low acid products. In these foods the time and temperature of the processing kills all spores. You will have a safe product if you can follow instructions.

Also be sure to adjust for the elevation as noted in the books.

Have a great canning season.

Althouhg new to canning (last year was the first for me), from what I read, I would second what James_1 said about not messing around with recipies. I have the big Ball Canning book as well as the smaller one, and between the two, there is pretty much anything you might want to make.

Any food you stick in a jar, place it in your pantry and eat it 3 months later has to be done properly. Like they said. Follow the recipes and directions to the letter. No substitutes unless prescribed or shortening of processing times and pressures. Most of all, make sure jars are sealed when you open them. If the lid pops off by itself when you remove the band, throw that jar away. At least the contents. You should always have to use force to lift the lid off the jar. Bacteria produce gasses while they are working. Gasses build up in the jar and break the seal on the lid. Usually, especially in tomatoes, they will begin to bubble and run down the side of the jar.
And you cant always go by smell. Just because the jar of tomatoes smell ok, dont mean its ok. Check that seal. On anything, not just maters. Also, watch for canned foods you buy, dont eat buy any cans that are bulging on the tops or bottoms. Tell the grocery store people about them so they can be removed from the shelf. Bacteria are everywhere, and nobody is perfect. Even Hunts, Del Monte, Bush's, etc. anybody can make a mistake, allow room for human error.
But, follow directions and recipes and learn what to look for, you will be ok.

Try the old recipe and eat a spoonful and see if you feel sick?

I am an experimenter and have modified some pickle recipes, but stick with the times they rec for non acid foods. But as you said it is tough finding the real info.

My 2 cents is they keep trying to add safety measures to protect us. In the old days it was all open kettle methods.

BTW, stock up on the lids, WO lids you are out of biz when trouble starts.

The USDA has recommended since 1947 that low acid foods be canned using pressure cookers.

What change are you referring to exactly?

quote:

Originally posted by allenwrench:
Try the old recipe and eat a spoonful and see if you feel sick? .

If it's botulism, enough of a taste to make you "feel sick" will kill you dead.

I've been canning since I was a teenager in the late 60's and I made my first Jelly.

Enough sugar or acid will prevent botulism from growing in food. The botulism spores are in the ground everywhere, but only grow in the absence of air.(like in a canning jar.) It isn't the botulism that is so poisonous, but the waste product. It isn't only in home canned goods either. Sometimes a professionally canned food will get swell-head, and that is likely to be botulism.

Botulism toxin is tasteless, and very poisonous. I was told the poison in a single can could kill a large city. Even a tiny taste can kill you(or your dog, or chickens... you get the idea.)

If you doubt any of your canned goods, boil the jar for at least twenty minutes at a full boil before tasting. Throw it away if it foams or smells bad.

While it is true there have always been people who tried to can food without a pressure canner, there was also a lot of summer sickness and death.

Don't take a chance. Use a pressure canner for all low acid foods.

mindwing

pressure canners are expensive for good ones, but they are way cheaper than a coffin and cemetery plot.

There might be some info to answer your question at this site.

http://www.fsis.usda.gov/Fact_Sheets/index.asp

Happy (and safe) canning to ya!
Bob

Oops! I posted the wrong link...

Try this one.

http://www.uga.edu/nchfp/publications/publications_usda.html

Another potential botulism source in home canned foods is certain pickled foods, in which the acid does not permeate the food entirely, and it is not pressure canned, because it is presumed to be of high enough acid. This happens with hot peppers which have been canned whole, and often with the stem on, and the inside of the pepper sometimes does not get the vinegar. I'm not sure how it gets infected with the botulism, if it this well sealed, but it happens frequently enough that I never pickle peppers, except sliced, in escabeche.

Dave

Ok, so it sounds like the newer emphasis on pressure canning was to simply make a fairly rare problem even rarer.

It wasn't, like undercooked hamburg, were the bugs got worse over time.

No! It is to make the problem non-existant!

Zero deaths from botulism is the goal.

Everything I "can", I use the pressure canner. Didn't know anything had been changed by anyone. A lot of folks I know use water bath canning for tomatoes, but I would just rather pressure can everything. Beans, tomatoes, squash, pumpkin, etc., all goes into the pressure canner. That Ball Blue Book has it down pat for canning!!