We've been eating these things every day for so long, we would be dead by now if this were the case.

When I share our recipe with friends, I always warn them to take it easy--not eat the entire muffin all at once. 1/4 cup of flaxseed is a HUGE slug of fiber, and people might have....consequences.

Thanks everyone for the links and suggestions. I think the restrictions of commercial production--preservatives, additives, etc.--probably preclude the convenience we enjoy with our home-made muffin kits, which we keep refrigerated. But you CAN try this at home!