When I did some reading on this subject in the past what I came across was that there is a difference between washed poppy seeds an unwashed poppy seeds which Is exactly as it sounds. Unwashed poppy seeds have a higher opiate content due to a thin coating on the outside that they likely picked up while still inside the seed pod. That seed pod is the primary source of opium. So, basically It can boil down to what company the poppy seeds were sourced from and whether or not they had been rinsed off with water prior to hitting the market.