Animal organ meats tend to accumulate pesticides, herbicides, heavy metals, synthetic growth hormones and antibiotics, etc. Livestock operations use the cheapest animal feed they can find, turning it into as much animal mass as they can with hormones and antibiotics, and bioaccumulation of toxins becomes an issue.<p>Eating anything coming out of that pipeline is probably not that great of an idea, but organ meats are the least advisable portion.