The foul end-stage of protein and fat decay, when anaerobic microbes dismantle meat, fish, and other rich foods into ammonia, hydrogen sulfide, cadaverine, and putrescine. The unmistakable stench signals food that is not merely stale but inedible and potentially hazardous, as the same conditions can favor pathogens and toxin producers. Butchers and fishmongers read its early signs, off-odors, slime, discoloration, as the absolute limit of saleability. Prevention is the classic trio of cold, cleanliness, and speed from slaughter or catch to the consumer.