Is it safe to dry homemade sausages that have been cured with Cure #1 in a dehydrator instead of hanging them out to slowly dry? The dehydrator I have goes from 90F to 190F.
Safety concerns aside (although this is related), the issue with this approach is case hardening. That is, the sausage, salumi, or whole muscle dries too quickly and unevenly. The exterior becomes too dry, while the interior is not dry enough. The hardening of the exterior, then further limits the drying of the interior. Hanging meat to dry, in the appropriate environmental conditions, leads to an evenly and appropriately dried final product. I would not recommend a dehydrator in this situation. With a constant warm airflow, case hardening is inevitable.
Typically, the hanging of meat is done to promote certain microorganisms, so that they can ferment certain sugars in the meat. This leads to the production of lactic acid by the various strains of Lactobacillus microbes. This can only be done when the meat is correctly cured.
A dehydrator is not typically meant for meat, but as a way to preserve certain veggies and spices. The temperature you mention would just partially cook the sausage, but probably leave it under-cooked. If this is a pork sausage then it could be quite dangerous. It would also kill off the Lactobacillus, ruining any chance of a ferment.