Evaluation of bactericidal efficiency of Siberian fir oil

The bactericidal activity of Siberian fir essential oil (Abies sibirica) was studied by aerosol method. Siberian fir essential oil was dissolved in 96° ethyl alcohol with addition of 0.01 % aqueous solution of DMSO, TWIN-80 and distilled water. The concentration of essential oil in the solution was 0.045 g/cm3 . Staphylococcus aureus and Escherichia coli which were isolated from pathological material of respiratory tract of turkeys and possessing high resistance to antibacterial drugs were used as test cultures. S. aureus and E.coli test cultures were sprayed inside a sterile test chamber with a volume of 0.62 m3 creating concentration in the air of (6,2 ± 0,06) × 104 CFU/m3 and (4,6 ± 0,02) × 104 respectively. A fan with a capacity of 25 m3 per hour was used for prevention of rapid settling of microorganisms inside the chamber. After that 4 cm3 of the solution of Siberian fir essential oil was sprayed using the spraying equipment. During the experiment, control of the air contamination inside the test chamber was carried out by the sedimentation method. Sampling was carried out before con tamination by the test cultures, immediately after spraying the microbial suspensions, 30, 60, 90, 120 minutes and 24 hours after spraying the solution of Siberian fir essential oil. The seeds were cultured in a thermostat at the temperature of of 37,0 °C. The test results were recorded after 24 hours. The calculation of air contamination by bacteria per 1 m3 was carried out by the Omelyansky method. The results of the studies showed that the concentration of Staphylococcus aureus in the air environment of the test chamber decreased 31 times in 30 min after atomization of fir essential oil aerosol, 103 times in 60 min, 147 times in 90 min, and 248 times in 120 min. Also, aerosolized application of fir oil reduced the concentration of Escherichia coli in the air environment 5.3–fold after 30 min, 16.4–fold after 60 min, 82.1–fold after 90 min, and 242.1–fold after 120 min. It was noted that with increasing exposure time, the number of the test microorganisms in the air environment of the test chamber decreased.