According to Douglas Baldwin's site the minimum safe temperature for Sous Vide is 54.4C. I assume my circulator could be a few tenths out so never set it below 55C.
Rare is generally considered to be less than 50 deg C, sometimes as low as 40 deg. The USDA (I think) recommends only eating steak at medium rare or higher (55 deg). Does this mean you shouldn't sous vide a rare steak?