According to the USDA, any food held in the so-called temperature "danger zone" (between 40°F and 140°F) for more than two hours presents a risk of food-borne illness from the growth of pathogenic bacteria — whether it's cooked sous vide or by conventional means. In truth, these numbers have a built-in buffer zone, so 130ºF is a much more accurate cutoff point. Harmful bacteria can't grow above that temperature, and at around 135ºF, most bacteria will actually be destroyed after a few hours, making pasteurization possible.
The precision temperature control of sous-vide cooking means it actually has the potential to be safer than traditional cooking methods. (This is exactly why one of its first major applications was making hospital food). And most home sous-vide circulators will let you know when you're cooking in the danger zone.
Anyway a lot of times you smoke briskets ect your food will be in the danger zone for awhile and it is perfectly fine. This is why I wont probe my meat until further in the cook where I know it is 140 otherwise you are introducing surface bacteria to the otherwise sterile center. With proper finished cooking temps you shouldn't have to worry anyway.
I look at the danger zone is more of a hold temp cook a turkey stick it on the table with a temp at 90 degrees for 4 hours eat turkey get sick.