The reason to sous-Vide burgers is that you can cook to lower temps & still be safe.
Federal guidelines suggest the following temperature and time combinations, applicable to sous vide as well, to kill salmonella and E. Coli bacteria in food.
130F for 86.42 minutes
135F for 27.33 minutes
140F for 8.64 minutes
145F for 2.73 minutes
150F for 51.85 seconds
160F for 5.19 seconds
165F for 1.64 seconds
Using traditional cooking techniques it was very hard to heat up the very inside of food to a high enough level to kill the bacteria without overcooking it, and overcooking the outer layers even worse. Sous vide allows you to cook chicken breasts to a perfect 160 degrees for 5 seconds or beef at 130F for 86 minutes and kill all the bacteria without overcooking them