This article is from the Food Preserving FAQ, by Eric Decker firstname.lastname@example.org with numerous contributions by others.
Insure your crock pot is clean and sanitized before you start. Be sure the
grease you pour into the crock is always nice and hot as well as the meat.
Keep everything as clean as possible. Don't use the came cooking utensil to
take the meat out of the pan as you used to turn or handle the raw meat.
Leave the utensil you use to move the meat from the pan into the pot in the
frying pan where it can stay hot and therefore sterilized. Do not touch the
cooked meat with anything except the cooking utensil you transfer the meat
from the pan to the pot with. When putting meat into the crock, don't touch
the sides of the crock pot and don't touch the meat. Cover the crock with a
lid when not putting meat or fat into it. Remember, your success depends
entirely on insuring that not one cell of bacteria is permitted to remain
alive in the pot. And on using the meat, schedule things out so you plan on
using the last of the meat within 6 weeks. (This was not a problem for the
early folks as they often had 10 or more children.)