See attached photos. 1. bad potato purchased today (4/22/2017). Green. 2. bad potato in Campbell's vegetable soup. The black on the potato can be used to trace distribution from source to destination. I have returned potatoes, red onions, steak, ground sirloin, and Quaker oatmeal SEVERAL times over the past month. Lakeland, Florida is Publix headquarters.
Japan has been hit by a massive potato chip shortage "Many of the imported potatoes did not reach the required level of quality, and we could not cover our full production range," https://munchies.vice.com/en_us/article/japan-has-been-hit-by-a-massive-potato-chip-shortage
The green on the potato is a natural chemical called Solanine. It's basically a natural pesticide that is poisonous. It happens when a potato is exposed to too much light. Most of the time it can just give you the shits, but it has been known to cause Hallucinations, paralysis and even death. 3 to 6 mg of solanine per kg of body weight can be considered fatal.
I remember reading years ago that the black spots on potatoes can cause birth defects http://msgboard.snopes.com/cgi-bin/ultimatebb.cgi?ubb=print_topic;f=76;t=000095