The current USDA guide line for cooking chicken is 165F but if you maintain the temperature for a specified longer duration, you can safely cook chicken at much lower temperatures. The amount of fat in the meat is also another factor (meat with more fat requires more time or a higher temperature). This chart indicates that for chicken breast, at 165F-160F, salmonella is killed almost instantly (i.e. as soon as the meat reaches this temperature, it is safe to eat) and at 140F you have to maintain the temperature for more than 30 minutes but less than 40 minutes. So if you use sous vide and maintain the given temperature for the specified duration, you should be able to cook chicken (or other meats) safely at lower temperatures than indicated by the USDA guide line. (Again try at your own risk).
It sealed with a good vacuum. I preheated my Anova sous vide machine at 140F which took only few minutes since I started with the hottest water out of our tap. I placed two vacuum sealed chicken breasts into the heated water and let it cook for 3 hours (as per the recipe, at least for 2 hours). I am estimating that the internal temperature of the center of the thickest part of the chicken would be at 140F after 30 minutes (or at the most, 1 hour. Actual "cooking" or coagulation/denaturing of proteins must take more time to occur at this temperature).
When the chicken breast came out, the meat was opaque and only a small amount of juice was seen in the pouch (left upper in the picture below).
I removed the chicken from the pouch. After blotting any moisture from the surface (upper right), I seared the skin side on high heat with a small amount of vegetable oil (lower left). After 1 minute, I flipped the pieces showing nice brown color (lower right) and set it aside on a plate. I then poured the juice accumulated in the pouches in the same frying pan and briefly reduced (since the pan was hot this took only 20-30 seconds). I finished the sauce with a few thin pats of cold non-salted butter. Since some salt and pepper came off the chicken into the sauce and the chicken was well seasoned, I did not add any more seasoning.
The cut surface was just very slightly pink and very moist (actually not as pink as shown in the picture). Again, we had other dishes and we just tasted a few slices with the pan juice I made. The result was better than my sakamushi 酒蒸し or sake-steamed chicken breast (especially when I use the microwave to make it, In the microwave the chicken breast sometimes comes out stringy with over cooked areas). I was impressed by how quickly the skin browned. It must be because it had already cooked and was warm and I blotted any moisture before searing (evaporation of liquid cools the surface and make searing/browning slower). Although, this time, this was a test run of sous vide chicken breast, with this success, I will try this as a more complete chicken dish.