One thing to check on jerky in the dehydrator is what temperature it will be cooked at. This could be a reason it is recommended to freeze the meat to kill parasites and other microorganisms. Typically jerky is made by exposing it to a lower level of heat over an extended period of time. Due to this often jerky does not reach temperatures meat typically does when cooked via other methods. I could be wrong, but I believe most meat is recommended to reach an internal temperature of 145-160 degrees Fahrenheit to kill parasites, bacteria, etc. Sometimes jerky is not cooked at that temperature level in a dehydrator.