The starches also include flour, tapioca, and no barley, either. Starches change the density, also the ph of a food. Flour has a very high ph level.
This is why you don't can fats/butter/oil.The fats surround particles of food, allowing botulism to even survive pressure canning. I know there are a few tested recipes that allow for adding oil to saute in, but those recipes are highly tested for safe preservation. That, and a few HIGHLY acidified marinated pickled items. Again, not all foods can be processed in that manner.
No bacon added to green beans for above reason.
Some foods protect the botulism spores differently than others.
No thickening of tomato product before canning, not salsas, not ketchup, etc. not even with Clear Jel.
Clear jel is only approved for canning pie fillings or jams. It is because they are high acid foods, not low acid or borderline acidic foods.
The canned breads and cakes are not safe even for short storage. They should never be sealed. Only made and put in the fridge for a few days or frozen. The seal will create the anerobic condition in which botulism grows.
No canning of pickled eggs. I know someone said eggs, but this include pickled eggs.
Potatoes must be peeled before canning. The peel harbors the botulism spores since they were in the dirt. No amount of scrubbing can insure it is gone. It is the stuff you can't see that can grow.
That is all I can think of to add right now.