IMHO 129˚F/54˚C for a minimum of 2 hours from room temp should make for a rare steak. The starting temp and length of time are important. Provided you reach and hold the minimum target temperature for a couple of hours you should be safe – at the lower end of the safe-scale you want to cook longer, not shorter. The length of cooking time makes up for the lower temperatures ability to destroy pathogens. Obviously you don’t want to cook at length BELOW safe temps!
We’re talking whole muscle here, where pathogens from butchering are likely on the outside of the meat – ground up meat presents greater danger and I would cook at higher temps and for longer times if I were to do so.
If you’re really worried about the source and safety of your meat then a) increase time and/or temp, b) spray your steaks down with vinegar before sealing them in bags, or c) pre-sear the steaks (which you can also post-sear again afterwards) – the pre-sear adds lots of flavour through the Maillard reaction.
I routinely poach from frozen, adding an hour for each 1/2" depth of penetration required (add and extra 2 hours for your 2" steak to reach the centre at a depth of 1").