No No No Dairy when Canning
and the same goes for any pasta noodles or rice. These practices have not been challenged in microbiology studies to see if it is safe.
Milk is not something you can add to your canned goods. The amount of heat even when pressure canning would never be able to kill the harmful bacteria. The amount of heat that is needed would make the quality of your goods bad.
NO ONE has ever developed a canning process to safely use milk when canning.
The fat in these products (oil and milk) encapsulates any bacteria which includes botulism and this encapsulation prevents the heat used impossible to kill the bacteria. That means it will insulate the bacteria spores and let that bacteria spoil anything you preserve with milk. Remember milk has a low PH. Add it after you open it to prepare for eating!
For further information
Don't let the Milkman get you!!!!!
Safety with soups
Here is a page on insuring safe canned foods:
Safe canning soups