Food Dehydration: is the process of removing water from food (usually through evaporation), which in turns prevents the growth of microorganisms and bacteria. **If using dehydrator or oven, pre-heat to 145 degrees for 15-30 minutes prior. **Be sure to check your jerky often. Do not rely on the times given. Oven â lay out the strips on a cookie sheet lined with foil, in rows and a single layer.