I mentioned this in a past diet log, but I wanted to say it again.
I'm compiling a list of sodium nitrite-free beef jerky brands on my beef jerky review blog here...
If you're looking for beef jerky with no sodium nitrite, look for packaging that says, "no preservatives", or "all natural ingredients". It's not guaranteed that it will be free of sodium nitrite, but most often it will be.
Generally, sodium nitrite is not that harmful if you eat beef jerky in limited quantities. But if you're going to eat a lot of it as part of a diet regimen, then you should stick with beef jerky that doesn't have it in it. It has been linked to colon cancer and lung disease.