Control of Fungal Spores on Surfaces with UV-C Exposure Necessitates Complete Inactivation to Prevent Mycorrhizal Network Establishment

• DOI: 10.1021/acs.est.4c12666
• Publication Date: 2025-03-27T03:04:07Z
• Authors: Zhe Zhao; Han Fu; Li Ling; Tingyu Li; Avery Brewer; Anca G. Delgado; Paul Westerhoff

Mold infestations on surfaces present significant challenges to public health. Germicidal UV-C irradiation effectively inactivates spores suspended in water, yet information surface spore mitigation is surprisingly absent. We show the effectiveness of 265–275 nm light mitigateAspergillus nigeron nutrient-rich surfaces. molds differs from inactivating water due unique characteristics mycelial structures. Complete preinactivation all viable cells during exposure crucial prevent mycelia formation; otherwise, even a single can gradually spread, covering by producing progressive structure. A dose 144 mJ/cm2 265 LEDs achieved complete at lower concentrations (100–1000 CFU/plate), while higher required increased doses. Intermittent duty cycling delivery (10 min ON then 50 OFF) 275 delivered side-emitting optical fibers comparable continuous irradiation. Insufficient induced more resistant structures that shielded live beneath. This study highlights molds, or sustained inhibition light, effective than posttreatment. Mycelial alteration triggered sublethal stress helps persist unfavorable environments, where microbial control goal.