Yesterday while I was in Paducah I finally scored the plastic mesh I've been looking for to make screens for the dehydrator trays. The screens are to keep small pieces from falling through the trays. The screens sold by the manufacturer cost $3 each, are flimsy, don't fit to the edge of the tray (wasting space), have divots in the side (I think to "help" you remove them) (wasting more space), and I just don't like them.
I've been looking for alternatives. I shopped online and never did find mesh that said it was food grade. I finally decided that in the grand scheme of things it wasn't that much of an issue for us. If you're one of those who has forsworn all plastic touching your food, then ignore this post. You'll have to find your own solution.
After hitting multiple stores in Paducah and Memphis - Michael's, Hancock Fabrics, Joann's, Bed Bath and Beyond, Home Depot - I finally found what I was looking for in Hobby Lobby. They are plastic mesh pieces that, as of 06/19/2011, cost $0.49 apiece. It takes two pieces for one tray making the total cost per tray be $1.00.
What you do is cut the screens to fit your dehydrator trays. It took me two screens because I've not been able to find the mesh in pieces large enough to cover a whole tray. Therefore, I cut each piece to be one half of a tray, including a bit of overlap for coverage, and use two pieces.
I used my "fruit leather" screen to trace a template on a piece of newspaper and cut that out, including the interior hole which I cut a bit smaller than the fruit leather hole. I folded the template in half to find the center line and cut down that. I used the template to trace the cutting lines on the mesh with a big sharpie. Easy peasy.
Here's a pic of the screens in a tray.
Here's a pic of the corn I dried overnight using the mesh screens. Fantastic! All the corn stayed on the trays on which it was placed and kept the drying nice and even.