I have been having an issue with my plaque assay for a few weeks now, I am working with a soil sample I inoculate a certain amount of virus PFU/mL into the soil then use some recovery method to recover the virus sample and run a plaque assay using methyl cellulose as an overly but the problem I keep having was mold growing on the sample which prevents seen any place on the sample. I would greatly appreciate any technical advice on how to get rid of the mold from the sample as we don't want to autoclave the soil or use UV radiation I would prefer using any mold inhibitory substance I have used Anti-Anti which it did not work as it only inhibits bacteria and fungi so is not efficient for my work. Thank you.