One of the most relevant areas of scientific support in the field of veterinary medicine is the development and comprehensive evaluation of the effectiveness of antimicrobial agents under current requirements and taking into account the spread of antibiotic-resistant strains of pathogens. Today, among the promising ways to expand the range of disinfectants to ensure effective general veterinary and sanitary, and antiepizootic measures in livestock production is the use of modern chemical and biotechnologies, in particular those based on metal nanoparticles. The study aimed to investigate the spectrum of antimicrobial action of a mixture of binary nanoparticles of Ag, Zn, and Cu metals. The biocidal properties of the nanocomposite with a metal concentration of Ag — 367.2 mg/l, Zn — 287.76 mg/l, and Cu — 4.8 mg/l were studied on the model of cultures of enterobacteria Escherichia coli and Staphylococcus aureus, micromycetes Aspergillus flavus and larvae of helminths Toxocara canis using conventional methods. Microbiological studies have shown that the Ag-Zn-Cu nanocomposite exhibits bactericidal properties against the test cultures of S. aureus and E. coli and disinfects 100% of the test objects (tile, wood, cambric) contaminated by them at a concentration of 5% at an exposure time of 3 h and a concentration of 10.0% at an exposure time of 1 h. The Ag-Zn-Cu nanocomposite at a concentration of 5.0% with an exposure time of 1 h has a bacteriostatic effect on S. aureus and E. coli: on average, 98.2 and 99.4% of the cells were inactivated on tile, 95.3 and 97.5% on wood, and 98.4 and 99.1% on cambric, respectively. The nanocomposite at experimental concentrations (10.0–75.0% solution) at 20 ± 0.5 °C for 60, 120 and 180 min showed fungicidal properties against the test culture of A. flavus. In addition, a significant fungistatic effect against A. flavus was found with an 8.0% solution; a slight growth inhibition was observed with a 6.0% solution. The nanocomposite in 3.0 and 5.0% solutions showed neither fungicidal nor fungistatic properties under the above conditions. Treatment of the test culture with 5.0% and 10% solutions for 9, 12, 24, and 48 h affected the development of T. canis eggs and caused their death at the larval stage (larvae stopped moving and began to be destroyed). It was found that at an exposure time of 48 h and a concentration of 10.0%, the nanocomposite showed disinfestation activity, delaying the embryogenesis and invasive ability of larvae, and disinfected test objects contaminated with helminth eggs with high efficiency (up to 88.3–95.9%). The Ag-Zn-Cu nanocomposite exhibits bactericidal properties against the test cultures of enterobacteria S. aureus and E. coli and disinfects the test objects contaminated with them at a concentration of 5% at an exposure of 3 h and a concentration of 10.0% at an exposure of 1 h. The lowest concentration of the nanocomposite ensured complete inactivation of the A. flavus test culture at 20 ± 0.5 °C was 10%. The nanocomposite at a concentration of 10.0% for 24 and 48 h disinfects test objects contaminated with T. canis eggs and reduces the invasive ability of the larvae. Thus, the new data on the spectrum of biocidal action of metal nanoparticles make it possible to improve the development of innovative directions for controlling the level of pathogenic and opportunistic microorganisms in the environment
