Polyurethane ok to use?

I was looking at building materials at homedepot today and I saw that I can get 1/2 sanded pine plywood for about half the cost of melamine particle board...

Ply wood is much stronger and less likley to sag or bow than particle board but I want somthing that can be wiped clean.. The pores in wood can harbor all kinds of nasties...

Can polyurethane be used to coat the ply wood if given ample time to harden and fumigate?

Water based Poly in multiple coats is most often used safely on wood cages and racks, but you have to make sure each coat is dry and leave the whole thing out to cure for days before you can use it.

With the cages I plan to build, I'll be using 'PolyShades' which is a water based stain and poly in one. :)

yep... some people will tell you 'no'. but the truth is, there are a TON of people that use it with no problems as long as you let it cure. the sun's natural UV rays are the best/quickest method.