Mold fungi spoil food and degrade its sensory properties, creating risks associated with mycotoxin formation. Dairy enterprises use permanent antimicrobial coatings to improve the sanitary treatment of equipment and extend product shelf life. This article describes the fungicidal activity of polymer compositions based on polyethyleneimine (PEI) and polyacrylic acid (PAA) modified with silver. The substances were tested against seven mold strains (Penicillium gladioli, Penicillium verrucosum, Penicillium rugulosum, Penicillium polonicum, Cladosporium pseudochalastosporoides, Botrytis cinerea, Aspergillus wentii) isolated from dairy processing facilities. Fungicidal activity was assessed by the presence or absence of growth on solid and in liquid Sabouraud media at exposure times ranging from 5 min to 96 h. The fungicidal activity of the base interpolyelectrolyte complexes (PEI/PAA) depended on their composition: pure PEI suppressed the growth of six strains, and the 3PEI/1PAA complex suppressed two, while 1PEI/3PAA was inactive. Silver significantly enhanced the fungicidal effect: the addition of silver ions (Ag⁺) to the 3PEI/1PAA complex expanded the spectrum of suppressed strains from two to seven, providing universal activity within a five-minute exposure time. Silver nanoparticles increased the number of sensitive strains for the initially inactive 1PEI/3PAA complex from zero to six. Furthermore, silver nanoparticles allowed the 3PEI/1PAA complex to maintain full activity for 96 h, whereas the unmodified complex lost its efficacy after only 24 h. Thus, the use of silver increased the number of suppressed mold species by 3.5–7 times compared to unmodified complexes. In this research, polyethyleneimine and polyacrylic acid demonstrated high potential for novel fungicidal coatings in the food industry.
Yushina et al. (Wed,) studied this question.