Here’s an article from Applegate Farms about the confusion surrounding the terms “uncured” and “no nitrites” on packages of luncheon meats and hot dogs. http://www.applegatefarms.com/inthenews/response.aspx

The take aways for me:

• Naturally preserved lunch meats/hot dogs (those labeled “uncured” or “no nitrites”) ARE cured (often with celery juice or powder), and DO have nitrites, sometimes in greater amounts than their conventional counterparts. In other words, they are are “safe” from spoilage as the others, but if you thought you were not eating nitrites, think again.
• Some people think a nitrite is the same as any other nitrite, but Applegate describes the difference between the synthetic and natural nitrites in this way:
  

  “Synthetic sodium nitrite is created by the absorption of nitrogen oxides (derived from ammonia compounds) in a liquid solution of either sodium carbonate or sodium hydroxide.  The resulting slurry is dried and pink dye is added to distinguish it from table salt.  According to the Food Chemical Codex (3rd addition, National Academy of Sciences), industrial sodium nitrite is allowed to contain residual heavy metals, arsenic and lead. While some may say, “nitrites are nitrites,” those derived from celery juice and sea salt are clearly different, and the USDA agrees, hence the different labeling requirements for products cured this way.”

• TheFDA has to date not allowed the natural meat industry to clarify the actual ingredients/process on their packaging.

For my part, I feel far more comfortable feeding my family what is naturally occurring in celery, than a synthetic version with residual heavy metals of arsenic and lead.