Pressure Canner Explosion

[coronabarb]

Sorry for the confusion. Let me see if I can clear it up. When canning high acid foods such as fruit and jams/jellies, botulism is not a concern due to the sugar binding the moisture and making it unavailable to the bacteria. You can still get mold. Water bath canning is sufficient.

When you are canning low acid foods, the tested recipes call for pressure canning to insure that the food interior reaches 240 for a sufficient time period to destroy the botulism spores. Notice I say "tested recipes"...because in the lab, they have devices that can be inserted inside the jars so they know what is going on. They can calculate the right amount of time to make the food safe without overcooking it and ruining it.

With salsa, you are canning borderline (tomatoes) and low acid veggies. The tested recipes are calculated to use a certain amount of acid (vinegar or lemon/lime juices) to raise the acidity and make it safe to water bath can. But there are also density issues that are taken into concern. If there are no tested recipes for pressure canning salsas, it could be that the time required to heat the interior to the required temp and hold it there for the required amt of time would render it mush. I am guessing...I would have to look further into it for a more exact reason. But if the usda has not published a tested recipe, then how do you know how long you must process to hold that interior long enough to kill the bot spores? You don't.

So to answer your question Carolyn, yes botulism can be an issue with a pressure canner IF the food is not processed according to tested directions. Several things can go wrong. For instance, if the pressure drops below the required number while processing, one needs to bring it back up to pressure and start the timing all over again...or any possible spores won't be killed. Both methods are safe for what they are intended for if directions are followed. For salsa, the acidity is changed with the addition of acid to make it safe for wb canning.