An uncured ham is ham that has not had any nitrates or nitrites added to it. Nitrates help preserve the color of the meat, making the ham more appealing to consumers. There is research indicating that intake of excessive amounts of nitrates or nitrites increasing the risk of developing cancer; there may, however, be some naturally occurring amount of nitrates or nitrites in uncured ham, but have been intentionally added.
There are many stores that carry uncured ham. Whole Foods Market carries Wellshire Farm uncured ham of several kinds. Trader Joe's offers uncured spiral half and quarter hams. Most chain stores carry Hormel Nature Choice Deli ham, which is also uncured.