Maybe some overkill being suggested. We converted the small clothes closet in our Hunter Compact-II to a pantry (after converting the loo to a huge closet and porta-port garage)
I used 1/2" x 1" maple strips along the sides, front and back edges of 1/8" birch plywood shelves. We freely load anything we want on the without any failures. If your closet is a lot wider (mine is 12") you might want to run an extra support across the middle. We have since added 3/8" aluminum angle across the front edges
Those side supports should be more than enough with the wire shelves. If not, you are putting to much weight
on them anyway....