Originally Posted by phatch
Usually in those cases, the sausages are quite "dry" and the salt concentration is high. There are also lactobacillus cultures involved in some cases that tend to fend off other bacteria. Temp and humidity are also important for this technique and will not succeed in all climates.
There's a Facebook group, The Salt Cured Pig, that focuses on such things. These guys are SERIOUS about it, some are professionals that sell products, some are dedicated hobbyists that have special curing rooms built to precisely control the curing environment, work with farmers to raise certain breeds of pigs under certain conditions - that kind of serious. And also a few folks like me who just make bacon and fresh sausages from time to time, though someday I may try making a real country ham myself.