Sous vide top side beef joint - set temperature lower than it should be
You should be ok.  You could err on the side of a longer cook.  Your main concern between 50C and 52.3C is Clostridium perfringens, which, according to Douglas Baldwin can grow at up to 52.3C (other pathogens of concern stop growing at 50C). He further points out that listeria is the most difficult pathogen to kill, but it takes less salmonella and E. coli to make you sick.  So....


  most experts recommend that you cook your food to reduce: Listeria by at least a million to one; Salmonella by ten million to one; and E. coli by a hundred thousand to one. You can easily do this when you cook sous vide: you just keep your food in a 130°F (54.4°C) or hotter water bath until enough bacteria have been killed. 


When have enough been killed?  It depends on the temperature and the thickness of your product.  Baldwin provides the information.   Raise your temp and cook on, but read Baldwin.