A lot of SV cooking is done in the danger zone, 40F-140F and so one needs to stick to certain tried and true techniques to avoid problems that may cause food poisoning. I'll mention a couple of things. There is a limit to how thick the meat can be in order for the transfer of heat from the water to the centre of the meat is done in a reasonable amount of time. When cooking is done you need to cool the bag and contends in ice water if they are not going to be eaten immediately. The reason for that is the contents are in an air tight bag, ideal for the growth anaerobic bacteria. Done correctly it is a wonderful technique but it needs to be done safely. Personally I would only do ground beef that I had ground myself and never from the store as it is very likely to have a much higher bacteria count than beef I've ground from a roast. These things and others apply to veggies as well as meat, etc. Again, that's my 2 cents:)