Jerky is finished in a dehydrator when it's completely dry, and it bends without breaking, although cracks may appear. To test the jerky, remove a piece from the dehydrator, allow it to cool for five minutes and bend to check for moisture.
The U.S. Department of Agriculture recommends heating meat to 160 degrees Fahrenheit to kill bacteria before dehydrating it. Many dehydrators don't operate that high, so the meat needs to cook separately before it's placed in the dehydrator. After the initial cooking, a constant temperature between 130 and 140 degrees Fahrenheit is recommended for the duration of the drying time.