Question: are walnuts treated with ppo?
Answer: Here, shelled walnuts are packaged. But almonds are the only nut, seed or dried fruit that must — by law — be pasteurized. If they're not steamed, they must be fumigated with a chemical called propylene oxide, or PPO. The regulation is a result of two salmonella outbreaks traced to almonds in the early 2000s.