So, while holding this meat at 135 F for the specified hours, in the last 30 minutes a fly touches down on the meat. Oops, the meat is no longer safe. In prac

So, while holding this meat at 135 F for the specified hours, in the last 30 minutes a fly touches down on the meat. Oops, the meat is no longer safe. In practice 135 F is a bit too cool to be very safe. Sure, the situation is more complicated than just one number for temperature and, sure, time is also important. And, sure, can still eat rare (never got as warm as 135 F) beef steak, say, a thick T-bone, if are sure the cow was healthy so that the interior of the steak is sterile and if have browned the outside to sterilize it. I remember Dad's remark on rare steak: "I've seen critters get hurt worse'n that and get well." IIRC for human fingers, pain to the touch is about 140 F. Still, for practice 135 F is a bit cool, especially for holding meat at that temperature for a long time as in the OP. Or, sure, if the meat at 135 F were in some sterile, air-tight situation for all the hours, okay, but that's not very realistic for a real kitchen.