## 3 Results and Discussion
### The Effect of Essential oils on the Viability of Bifidobacterium in In Vitro Conditions
fermentutum_, _L. helveticus_, and _L. paracasei_) were tested using the well diffusion method. The growth inhibition zones did not exceed 6.3 mm. The low sensitivity of LAB to coriander oil favored the production of fermented products by these bacteria [58]. Until now, the influence of essential oils or plant extracts on the viability of bifidobacteria has not been investigated. The available data in the literature mainly related to LAB and other essential oils, not those studied in our work, and only a few studies included bifidobacteria in this subject of research. [PERSON] et al. [59] determined the survival of _L. acidophilus_ LA-5 and _B. animalis_ subsp. _lactis_ Bb-12 in stored probiotic cygurt drinks enriched with essential oils from green mint (_Mentha spicata_), cualyptus (_Eucalyptus tamaldulensis_), long-leaf mint (_Mentha longifolia_), and _Ziziphora tenuior_ L. The authors found that the number of bacterial cells decreased during the storage of yogurts, and yogurts containing the eucalyptus essential oil showed the highest inhibitory effect. It is worth mentioning that the largest number of _L. acidophilus_ LA-14 and _B. animalis_ subsp. _lactis_ Bb-12 cells were observed in yogurts containing the green mint essential oil. Interestingly, _B. animalis_ subsp. _lactis_ showed better survival rates in all yogurt samples compared to _L. acidophilus_. The results presented by [PERSON] et al. [59] confirmed those obtained in our work despite the differences, among others, in the types of essential oils and dairy products tested. [PERSON] et al. [60] also found a decrease in the number of _B. lactis_ Bb-12 and _L. acidophilus_ LA-5 during storage  
\begin{table}
\begin{tabular}{c c c c c c c} \hline \hline \multicolumn{1}{c}{\multirow{2}{*}{**The Concentration of the Essential Oil Added to Cream**}} & \multicolumn{2}{c}{**Lemon Peel**} & \multicolumn{2}{c}{**Clove Bud**} & \multicolumn{2}{c}{**Juniper Berry**} \\ \cline{3-6}  & & **[Log(CFU/mL)]** & **[Log(CFU/mL)]** & **[Log(CFU/mL)]** & **[Log(CFU/mL)]** \\  & & **Mean** & \(\pm\)**SD** & **Mean** & \(\pm\)**SD** & **Mean** & \(\pm\)**SD** \\ \hline \multirow{4}{*}{100\%} & Cream & 8.3 & \(\pm\)0.4 \({}^{\text{a}}\) & 8.2 & \(\pm\)0.4 \({}^{\text{a}}\) & 8.3 & \(\pm\)0.4 \({}^{\text{a}}\) \\  & Sour cream & 9.3 & \(\pm\)0.1 \({}^{\text{b}}\) & 9.3 & \(\pm\)0.1 \({}^{\text{b}}\) & 9.1 & \(\pm\)0.1 \({}^{\text{b}}\) \\  & Stored sour cream & 7.8 & \(\pm\)0.1 \({}^{\text{c}}\) & 7.6 & \(\pm\)0.1 \({}^{\text{c}}\) & 7.5 & \(\pm\)0.1 \({}^{\text{c}}\) \\ \hline \multirow{4}{*}{50\%} & Cream & 8.3 & \(\pm\)0.4 \({}^{\text{a}}\) & 8.3 & \(\pm\)0.4 \({}^{\text{a}}\) & 8.1 & \(\pm\)0.4 \({}^{\text{a}}\) \\  & Sour cream & 9.3 & \(\pm\)0.1 \({}^{\text{b}}\) & 9.3 & \(\pm\)0.1 \({}^{\text{b}}\) & 9.2 & \(\pm\)0.0 \({}^{\text{b}}\) \\  & Stored sour cream & 7.7 & \(\pm\)0.2 \({}^{\text{c}}\) & 7.7 & \(\pm\)0.1 \({}^{\text{c}}\) & 7.6 & \(\pm\)0.2 \({}^{\text{c}}\) \\ \hline \multirow{4}{*}{25\%} & Cream & 8.2 & \(\pm\)0.4 \({}^{\text{a}}\) & 8.3 & \(\pm\)0.4 \({}^{\text{a}}\) & 8.2 & \(\pm\)0.4 \({}^{\text{a}}\) \\  & Sour cream & 9.5 & \(\pm\)0.1 \({}^{\text{b}}\) & 9.3 & \(\pm\)0.1 \({}^{\text{b}}\) & 9.4 & \(\pm\)0.0 \({}^{\text{b}}\) \\  & Stin an Iranian milk drink (doogh) containing essential oils from mint. The essential oil was used at two concentrations (1% and 2%) and its effect on the number of bacterial cells was found to depend on its concentration. Similar to [PERSON] et al. [59], [PERSON] et al. [60] noticed that _L. acidophilus_ were more sensitive than _B. lactis_. After 8 weeks of storage, the number of bifidobacterial cells in the milk drink decreased by 2 log(CFU/mL), while the number of lactobacilli cells was below the detection limit. This confirms the higher viability of _B. animalis_ subsp. _lactis_ Bb-12, as observed in our work. [PERSON] and [PERSON] [61] also studied the viability of probiotic _L. acidophilus_ and _B.