*2.4. Microbial Load in the Raw Material*

The ozone treatment resulted in a reduction of the microbial load in the plant material after 24 h of the conducted process (Table 2). The results of microbiological and statistical analyses showed the impact of ozone on the total number of aerobic bacteria colonies, in addition to yeasts and molds. Exposure of sea buckthorn berries to the effect of gaseous ozone at a concentration of 100 ppm for 30 min resulted in the lowest number of colonies of aerobic bacteria (cfu g−<sup>1</sup> ). The applied process conditions resulted in the reduction of the number of aerobic bacteria colonies by 3 log cfu g−<sup>1</sup> compared to the control (non-ozonated) sample. Similar effects of gaseous ozone were observed in the case of reducing the number of yeast and mold colonies on the surface of ozonated sea buckthorn berries. The number of yeast and mold colonies after the application of 100 ppm gaseous ozone for 30 min decreased by 1 log cfu g−<sup>1</sup> compared to non-ozone fruit. The reduction of the microbial load was due to the antimicrobial effect of gaseous ozone, which results from its strong oxidizing properties [24]. The influence of the ozonation process on the reduction of the microbial load of fruits has been confirmed in the studies of other authors. Piechowiak et al. [19] found a decrease in the total number of mesophilic aerobic bacteria, by 1.18 log cfu g−<sup>1</sup> , at 48 h after the first ozone treatment of raspberry fruit (8–10 ppm for 30 min every 12 h), compared to the control.


**Table 2.** Microbiological load of sea buckthorn berries 24 h after the ozonation process (*n* = 3).

Note: LSD for α = 0.05 for the impact of ozone treatment concentration (OC), ozone exposure time (OE), and the interaction between tested parameters (OC)/(OE). a,b,c,d,e statistically significant differences for the effect: ozone concentration (ppm) <sup>×</sup> ozone exposure (min).
