The important thing to consider though before attempting these methods, is whether or not your pathologist and/or your organization’s policies allow non-human tissue to be used as a control. Many want to be able to compare the control tissue with the specimens your lab processes, apples to apples comparison (no orange peel puns intended). Make sure that whatever you end up using is validated and appropriate for your lab’s requirements.
If you can’t use food, another viable option if you are in an organization with a microbiology department is to have them grow some control for you. When you receive fresh lung tissue, after it has been grossed put a few pieces in a petri dish and take it to microbiology. Have them add some fungal material and put it in the incubator to grow for a few weeks. Once you get it back from them, it can get the same fixation time and processing as the patient tissue.
Another option is just to use past positive patient tissue containing fungus, though that is much less of a fun science experiment!