This is a question I received in my inbox: Others have asked the same general question regarding different foods. The answer is the same no matter what you are canning. Oven canning is not safe or recommended.
I do not have a pressure canner but have the jars in the over, hot sauce to put in and have boiled the covers, I was going to put the jars back in the oven for about 20 mins on 200 then remove and hope that they seal.
Is this okay for spaghetti sauce with meat?
The method you are describing is oven canning. It is not a safe practice. I don't recommend it.
First let me mention that all canning jar manufacturers (as far as I know) don't recommend using thier jars in the oven. Not to can in, not to bake, in not even just to heat them up.
But here is an even more important reason this is unsafe.
Heating your jars in this way, there is a chance you will get a seal on your jars of spaghetti sauce. But just because the jars seal that doesn't mean the food inside is sterilized. That is where correct processing comes in. And especially with spaghetti sauce, where I'm assuming you've added onions, peppers and maybe other vegetables, a pressure canner is called for.
With any low acid food (like spaghetti sauce with veggies or meat) even if you get a seal on your jars, you are at risk of botulism. You must use a pressure canner if you want to be sure of safety.
Sealing does not indicate that botulism is not present.
Botulism is a type of food poisoning that can be very serious. You can not see or smell it in your food.
Botulism spores are harmless on fresh foods. When certain conditions exist, the spores will multiply and produce a toxin. It is this toxin that causes the type of food poisoning, botulism.
A pressure canner obtains the high level of heat necessary to kill botulism spores before they produce the deadly toxin. Oven processing will not do this.
Here is a link to a page where I discuss Botulism.
There are other concerns with oven processing any foods.
Pressure canning is the only method I would recommend for processing your spaghetti sauce.
Directions for canning spaghetti sauce with meat.
Since you have already made the sauce and you don't have a pressure canner, why don't you freeze it instead?
Simply put in freezer containers, and pop them in the freezer. Freezer bags work well too. They are easy to stack in the freezer taking less space.
I hope this helps.