Is this canning method safe to use for spaghetti sauce? (Boiling the sauce in the jars in the oven) This technique has been used by my family for decades but I'm wondering how safe it is to kill Botulism spores.


Step 1, cook the spaghetti sauce in a large pot (tomatoes, meat, fruits, vegetables, sugar, spices, etc).  pH unknown.
Step 2, Fill mason jars with water. Bring them to a boil by putting them in the oven.
Step 3, Put the boiling sauce in the jar.
Step 4, Put the mason jar lids on but not fully closed.
Step 5, Put the mason jars in the oven and bring the sauce again to a boil.
Step 6, Close the lids and wait until the lids become sealed.
Step 7, Wait until they cool down before storing them at room temperature. 


Thanks in advance!
No, it is not safe. You need a pressure canner. That's what the USDA says about anything containing meat:


  There are no safe options for canning these foods listed below in a boiling water canner.


See http://nchfp.uga.edu/how/can_04/soups.html for a table of pressures and processing times.