Ground beef needs nitrates because bacteria like e-coli live on the surface of meat….grind it…you have spread it all over every surface inside and out. Thats why it is always mentioned in the press for hamburger contamination; you hardly ever hear of someone getting sick from eating even rare cooked steak.
If you want softer jerky(I'm not sure why you want ground;often its because it eats softer) you can shread conventional whole muscle cut jerky and eat it that way…or…make it more like biltong; which is typically softer than jerky and diced up into cubes(like sugar cube size).Done after drying typical starting size is 1/2"x1/2" strip; for a lower sodium requirement.
This is a good site for all things jerky and biltong;
http://www.3men.com/
If that link doesn't work search; 3 Men With Nothing Better To Do
You can find biltong under the "mixed grill" section.Its typically made from game meat in Southern Africa; but beef is OK.Venison or elk is outstanding because of the super lean meat.
The more fat and marbling you avoid….the less salt you will need. They trap moisture and moisture is what breeds bacteria. I use VERY lean cuts (and mostly game meat) and use 1/2 the salt called for on typical recipes. Also by cutting thinner you avoid holding moisture and also can cut the salt required for curing.
Good bulk spices(cheap and high quality) and additional info can be found here;
http://www.sausagemaker.com/
I also recommend the book by the Sausage Makers founder Rytek Kutas(Great Sausage Recipes and Curing) if you require additional info on sodium nitrates and the type and use of this class of preservatives.
Thin+Lean+Good Airflow=Low Salt