Oldtime butcher shops closed every weekend. Ice, the only refrigerant available, could not dependably hold fresh meat for two days. To keep unsold meat from going to waste, the butcher soaked the meat in a strong brine or covered it with coarse salt to trigger osmosis. Meat is cured for one other reason, color. Using prague powder is what gives meat its pink color.
Osmosis is the movement of water across a membrane from weak solutions toward strong solutions.
When uncured meat remains in this range for more than 2 hours the growth of dangerous bacteria increases to a dangerous level. When meat is smoked, the environment is robbed of most if its oxygen. If this is combined with temperatures in the danger zone, the growth of the bacteria that causes botulism is increased. Botulism is an intoxication of the bacteria clostridium botulinum. This bacteria is anaerobic meaning that it requires an environment relatively free of oxygen to multiply.