If you play the pharisee game with the Watchtower you can't win. You won't lose but you won't win. There is one simple argument against the Watchtower teaching.
"There is nothing from outside a man that passes into him that can defile him; but the things that issue forth out of a man are the things that defile a man....Thus he declared all food clean."
Mark 7:14-23
You can eat blood sausage. Blood can be food. Just don't eat blood around Jews 'cause it may stumble them.
All of this bio-chemistry is unnecessary.