I started off with this Chuck Tender Roast that was marked down so I thought I would give it a go. Since it was such a long bath I decided not to put any salt, spice or anything on it. Vacu sealed it up and dropped it in the water. My Anova kept the temp steady at 131 the entire 48 hours. When it was time to pull it out I had the grill with a cast iron skillet on it ready to sear. Everything looked good and my wife and I was excited to open it up. Then this; There was a green slime all over it, looked a lot like a fine algae. It didn't have a smell to it other than a really beefy smell which it should have to begin with. Needles to say there was no way we were going to eat this thing. The inside looked amazing and smelled amazing. I had no choice after but to toss it in the trash. We really didn't want to take any chances. After running up to Captain D's for dinner I did some research on this and it seems that it was safe to eat and it happens with longer baths. There are many factors that could have led to it but 'they' say to give your meat a quick 30 second boil or pre-sear prior to starting the sous vide.It could have been the meat to begin with although it looked and smelled fine before starting. At this point I may never know but I wanted to pass this along for any who may have more info or may come across this in the future.