My understanding is that for acidic things, like tomato sauce and jam, you don't need a pressure canned because botulism spores can't sprout below a pH of 4.6. So therefore you don't need to get the temperature above 121oC to kill the spores, because the spores ain't doing anything anyway, you just need to get it to a temperature to kill off mold and bacteria.
So when we talk about canned meat, I assume we are talking about just straight ol' meat pieces in a jar, which would not be acidic enough to hinder botulism and therefore require pressure canning.
But if meat were mixed with something acidic, such as in spaghetti sauce, or maybe pickled, how is meat functionally any different from canning fruit or veg? Like, meat rots more easily because it has soft cell walls and is high in nitrogen for bacteria to feast on and putrefy, but regular canning would take care of that (just not the botulism). So if you add acid to stop the botulism, what's left to make the meat unsafe for consumption?
Unless there' other things that can survive regular water-bath canning?
by evange
4 Comments
Does the acidic sauce penetrate completely into even the smallest pieces of meat? Hint: it does not. Pressure can only.
The meat itself is not acidic enough, and the acid from the other food in the jar doesn’t fully acidify the meat. The fat present in even lean meat could also be a factor.
FWIW I pressure can tomatoes too. It’s just easier. And faster. 10 minutes at 10# pressure, vs what? 80 or 90??
Tomatoes are right on the edge of what’s is considered a safe ph. That’s why recipes in the U.S. call for adding additional acid before processing.
Adding meat, which is not acidic, changes the overall acidity in the entire product. I believe acidity is measured by total volume. So if you add an ingredient that is non-acidic, and significantly change the volume, you no longer have a safe ph.