## 3 Results
### Antimicrobial Properties of BWBs
#### 3.2.2 Effect of Fermented BWBs on Bacterial Growth Inhibition
plantarum_ (Figure 2) was recorded for beverages with the addition of ground flaxseed at 50% concentration, which inhibited bacterial growth of all tested microorganisms at a level exceeding 70% starting from 6 h of fermentation. The exception was _S. saprophyticus_, whose growth was inhibited at this level by BWBs from 8 h of fermentation. The greatest sensitivity to BWBs inoculated with _L. plantarum_, both without and with the addition of flaxseed, was demonstrated by _M. luteus_, the growth of which was inhibited by 90 to 100% at BWB concentrations of 25 and 50% from 6 h of fermentation. A strong antagonistic effect was also observed against _E. coli_, inhibited by BWBs after 6 h fermentation at levels of 43 and 41% (BWBs without flaxseed) and 82 and 65% (BWBs with flaxseed) at 25 and 50% concentrations, respectively. _P. fluorescens_ showed similar sensitivity; however, strong inhibition of bacterial growth was observed with BWBs at a 50% concentration. A longer fermentation time increased the antibacterial activity of BWBs against both gram-negative bacteria, with higher activity demonstrated by beverages with ground flaxseed. The least sensitivity to BWBs with _L. plantarum_ was demonstrated by _S. saprophyticus_, the growth of which was inhibited to a significant extent (>90%) only after BWBs fermented for 24 h (BWB without flaxseed) and after 12 h of fermentation (BWB with flaxseed) mainly at 50% concentration. In Figure 3, antimicrobial activity of BWBs inoculated with _L. paracasei_ is presented. Similarly to beverages with _L. plantarum_, the highest antibacterial activity towards all tested indicator bacteria was demonstrated by BWBs fermented for 24 and 48 h. BWBs without ground flaxseed inhibited the growth of _E. coli_, _P. fluorescens_, and _S. saprophyticus_ at a significant level (>80%) at 50% concentrations after 24 and 48 h fermentation. In comparison, at 25% concentration, high growth inhibition (89%) was observed only against _P. fluorescens_ by BWBs fermented for 48 h. In turn, BWBs with the addition of ground flaxseed demonstrated higher antimicrobial activity than those without. The significant inhibition of the growth of microorganisms was observed at a 50% concentration (above 60% of growth inhibition) after 6 h fermentation (towards _E. coli_ and _S. saprophyticus_) and after 8 h fermentation (towards _P. fluorescens_). Concerning _P. fluorescens_, the effect of the drink increased significantly after 8 h fermentation, while after 48 h, a high (>90%) inhibition of bacterial growth was found by the lower concentration of the beverages--12.5%. The most sensitive microorganism to the effects of drinks fermented with _L. paracasei_ (both without and with the addition of flaxseed) was _M. luteus_, for which growth inhibition in a wide range of beverage concentrations (6.25-50%) was observed after 6 h of fermentation. The BWBs fermented with the LAB mixture had similar antimicrobial activity to beverages fermented with single LAB cultures; however, the spectrum of activity at individual concentrations and incubation times was noticeably lower (Figure 4). Only in relation to _M. luteus_, BWBs fermented with the LAB mixture exhibited a strong inhibitory effect (in the range of 60-100%) after just 6 h fermentation in the entire range of tested concentrations (6.25-50%). The addition of ground flaxseed increased antimicrobial activity, but this relationship was observed mainly at 50% BWB concentration (against _P. fluorescens_ and _S. saprophyticus_) and 50 and 25% concentrations (against _E. coli_). BWBs without the addition of ground flaxseed showed a strong antibacterial effect (above 90% growth inhibition) against _E. coli_ and _S. saprophyticus_ after 48 h of fermentation (at 50% concentration), while against _P. fluorescens_, such a high level of growth inhibition was obtained both after 24 and 48 h fermentation at 50% beverage concentration.