https://foodprocessinghistory.blogspot.com/2013/05/history-of-meat-curing-process.html
History of Food Processing History of food processing is the history of transformation process of raw ingredients into food or food into other forms. Food processing dates back to the prehistoric age when crude processing including various types of cooking, such as roasting, smoking, steaming, fermenting, sun drying and preserving with salt were in practice. Food processing is probably one of the oldest avocations man has been involved with from time immemorial. HISTORY OF MEAT CURING PROCESS Prior to the development of refrigeration and cooling technologies, large quantities of salt were added to meats for long term preservation. The history of nitrate usage as saltpeter, in meat curing is lost in antiquity, but preservation of meat with salt preceded the intentional use of nitrate by many centuries. The origin of meat curing can be traced back to the third century BC, when Cato recorded careful instructions for the dry curing of hams. As early as 3000 BC in Mesopotamia, cooked meats and fish were preserved in sesame oil and dried, salted meat and fish were part of the Sumerian diet. By medieval times, treating meat with salt, saltpeter and smoke was common place and saltpeter’s effect to ‘fix’ the red color was well recognized. Meat curing was more of an art than a science in the early nineteenth century, but as a greater understanding of the curing process evolved in the late 1800s and early 1900s, the role of nitrate and nitrite in the formation of cured meat color and flavor became apparent. Toward the end of the nineteenth century, significant changes in meat curing had occurred. Various method of curing, namely dry, wet or pickle cures and combinations of the two were commonplace. The first dry cured meat products were probably inferior by today’s standards. Scientific principles of curing meats were not applied until the later part of the nineteenth century when the growing meat packaging industry began to search for ways to improve the quality. Since the mid 1920s, much advancement has been made in the meat curing industry. The direct use of nitrite greatly reduced the time for curing, since waiting for reduction of nitrate to nitrite was no longer required.
http://pods.dasnr.okstate.edu/docushare/dsweb/Get/Document-2055/ANSI-3994web.pdf