There has been great discussion over the acceptable setting for dehydrator temperatures in keeping food raw - that is, that the food itself is not heated over 118°F (this will kill the food's enzymes and other healthful nutrients). Many of the raw food movement leaders are divided on this topic.

The Excalibur Dehydrator company has done extensive testing with regard to this matter and has found that it is indeed safe to heat the air to a temperature of up to 140°F for no longer than 4 hours, without the food reaching above the critical temperature of 118°F. I have used a food grade digital thermometer in these burgers and found that the food did not, in fact, go over 110°F during the initial 3 hours.

Also, because I live in a very humid climate, I am not able to dehydrate for long periods of time at low temperatures (those below 105°F) as my food develops mold and bacteria growth resulting in spoilage.

Everyone must make their own decision regarding dehydrating temperatures. I hope this helps to shed some light on this controversy. Here are the links to the information and testing that Excalibur offers:

http://drying123.com/gen12a.htm
and
http://drying123.com/gen12b.htm