I used FULLY COOKED frozen bacon inside fresh beef rouladen (thinly sliced beef rolled with onion, mustard and bacon). I then browned the beef rolls, cooled them and then froze them for later use. Was it safe to refreeze the bacon a second time and then warm this dish up again when it is time to eat it?
Re-freezing is typically referred to in a different context. E.g., you took the something out of the freezer, let it thaw, and then put it back in the freezer in its original state.
Technically you are not 're-freezing' the bacon. You took the bacon out of the freezer and used it in your rouladen. Now you are freezing the rouladen.
It would be the same if you took a frozen meat of your choice and made spaghetti sauce and then froze containers of the sauce.
BONUS INFO ABOUT FULLY COOKED BACON - Fully cooked bacon is shelf stable until its expiration date as long as it remains unopened. Upon opening, it will need to be refrigerated. It can be frozen for longer term storage or storage past the expiration date opened or unopened.
The reason you find fully cooked bacon in a refrigerated case most, but not all, of the time, is because of consumer perception. Early on, it was realized that consumers (and even some retailers) weren't wrapping their heads around bacon not being refrigerated, even though it was fully cooked. So most stores put it in the dairy case next to uncooked or partially cooked bacon.
Yep, that is safe. If safe food is frozen and kept frozen (at or lower than that 0F, which home freezers typically are), the food will remain safe indefinitely.
Some foods take a quality hit being refrozen, but safety is not a concern.
Every entry in the Still Tasty database (the FDA, CDC and USDA site) has a comment to that effect.
Watch your time in the danger zone (40F to 140F / 4C to 60C). The rule of thumb is that high-risk food should spend no more than two hours (less conservative sources say four hours) between those two temperatures (cumulatively).
I agree with Jolenealaska. Bacon is a salted meat and mustard contains vinegar which helps in the preservation of meat and foods. Therefore; I believe you should be fine.