Preservation of foods with the use of salt is as old as human history. Simple necessity determined that cuts of meat could be preserved by treating them with a salt solution or by packing them in dry salt. Salt inhibits most spoilage by reducing the amount of water available for microbial growth. Salting as a means of preserving foods antedates written history. In the late 1800's and early 1900's nitrate and nitrite salts were discovered to "preserve" meats from the deadly botulism microorganism. Since that time these salts (nitrate and nitrite) together with sodium chloride (table salt) have been exclusively used to "cure" meats and make them safer.
Smoking meat imparts an attractive and appealing sensory property, in addition to preserving meats. Smoking has three preservation mechanisms: (1) heat, (2) chemical, and (3) surface dehydration. Heat from smoke cooking can kill microorganisms, depending on time and temperatures used. Some chemical compounds in wood smoke have an antimicrobial effect, contributing to food preservation, but these compounds are generally insufficient by themselves.
Curing and smoking foods for preservation is a little more complex than the other methods of preservation. Most cured and smoked foods are not preserved for room temperature storage. They must be refrigerated for safety.
Dr. Nummer wrote an extensive literature review on this topic when he was at the NCHFP. You can read it here.
NCHFP Resources - General info on smoking fish and meat, includes recipes.