Fungal Growth or Anti-Fungal is covered by Mil-Std-810, Environmental Engineering Considerations and Laboratory Tests.  The standard test method is 508.6 The key requirements for Anti-Fungal (Just as a byline, I started my career as a lab technician with Medical grade plastics and synthetic rubbers) is that the resultant mass after processing will not support fungal growth.
- To limit fungal growth, the resultant mass should be basic (PH 7+),
- Should not leave any carbohydrates.  This is crucial as almost all materials contain some degree of alcohols or alcohol derivatives.
So the trick is that prior to processing the material is supersaturated if it contains carbohydrates and causes any fungi to basically gorge themselves to death and after processing, all carbohydrates are evaporated free such that the resultant residues are minimal.  Often polyenes are added if there is a specific need to combat fungi as well as most 'enes' are anti-fungal as the double carbon bond cannot be respirated by fungi, killing it.