Fungal contamination is a major concern in the food production chain, particularly in the dairy industry. Traditional cleaning and disinfection techniques, though effective, can produce undesirable by-products ( e.g. chloramines) and may not comply with increasing consumers' demands for natural, non-toxic, and environmentally friendly solutions. This study explores the efficacy of biocides (ethanol, peracetic acid, acetic acid) and UV irradiation, alone and in combination, for different duration and intensities. Aspergillus brasiliensis ATCC 16404 was used as it is a reference strain in disinfection evaluation standards. Unlike many previous studies solely based on hydrated conidia, dry conidia were also tested to mimic airborne conidia that are responsible for contamination. Dry conidia were more sensitive to UV than the hydrated ones, but their aggregation could significantly reduce UV efficiency. Overall, they exhibited higher sensitivity to alcohol-based biocides. Finally, the effect of combination treatments was assessed using biocides containing less than 1% active compounds and short times (1 to 5 min) UV irradiations to allow survivors after each treatment. A synergistic effect, ranging from 1.33 to 3.93 log additional reduction, was obtained when an acid-based disinfectant was used sequentially with UV for both hydrated and dry conidia, thus achieving more than 4 log reductions. Detailed schematic of the individual and combined inactivation procedures on both hydrated and dry A. brasiliensis ATCC 16404 conidia. • The physiological state of conidia impacted the efficacy of fungicidal treatments. • Hydrated conidia were more resistant than dry ones to biocides and UV treatments. • Alcohol- and oxidizing-based biocides reduced conidia viability by >4 log. • UV treatment reached >4 log reduction for dry conidia but not for hydrated ones. • UV/oxidizing biocide combinations showed efficient synergistic effects.
Cadoret et al. (Wed,) studied this question.