# The Influence of Fermentation Vessels on Yeast Microbiota and Main Parameters of Sauerkraut
## Results and Discussion
### The Influence of the Vessel Used for Fermentation on the Yeast Microbiota of Sauerkraut
The yeast _Clavispora lusitaniae_ was first associated with the production of sauerkraut in our previous research [5], where they were the second most abundant yeast species, after _D. hansenii_. In the current research, they appeared on the fourth day of fermentation in glass jars and were the only ones detected on the following days (Figure 3). Our previous research has shown very good fermentation properties of these cultures, the ability to  
\begin{table} \begin{tabular}{l l|c c c|c c c c c|c c} \hline  & \multicolumn{2}{c}{**Vessel/Day**} & \multicolumn{2}{c}{**0**} & \multicolumn{2}{c}{**1**} & \multicolumn{2}{c}{**2**} & \multicolumn{2}{c}{**3**} & \multicolumn{2}{c}{**4**} & \multicolumn{2}{c}{**7**} & \multicolumn{2}{c}{**10**} & \multicolumn{2}{c}{**14**} & \multicolumn{2}{c}{**SEM 1**} & \multicolumn{2}{c}{**Sig. 2**} \\ \hline pH & Glass & 6.01 f & 5.78 ef & 5.73 ef & 4.64 c & 4.10 b & 3.82 ab & 3.81 ab & 3.73 a & 0.17 & *** \\  & Stoneware & 6.01 f & 5.70 e & 5.57 e & 5.13 d & 4.53 c & 4.06 b & 3.91 ab & 3.86 ab & 0.19 & \\ \hline \multirow{2}{*}{Lactic acid} & Glass & 0.00 a & 0.87 ab & 10.05 ab & 3.74 abc & 4.42 bc & 12.42 efg & 15.78 g & 15.37 f & 1.40 & *** \\  & Stoneware & 0.00 a & 2.01 ab & 11.6 ab & 2.57 ab & 2.75 ab & 6.95 cd & 11.65 ef & 10.12 e & 0.86 & \\ \hline \multirow{2}{*}{Oxalic acid} & Glass & 0.31 abc & 0.36 abc & 0.54 c & 0.30 abc & 0.50 bc & 12.5 e & 10.0 d & 0.36 abc & 0.07 & *** \\  & Stoneware & 0.31 abc & 0.53 c & 0.22 ab & 0.21 a & 0.39 abc & 0.82 d & 0.96 d & 0.15 a & 0.06 & \\ \hline \multirow{2}{*}{Acetic acid} & Glass & 0.00 a & 0.98 e & 1.60 g & 0.47 b & 1.52 fg & 3.75 k & 2.84 j & 0.89 de & 0.24 & *** \\  & Stoneware & 0.00 a & 0.64 bc & 0.73 cd & 0.84 de & 0.99 e & 2.38 i & 1.39 f & 2.07 h & 0.15 & \\ \hline \multirow{2}{*}{Succinic acid} & Glass & 6.22 f & 5.85 f & 8.48 g & 3.53 d & 3.74 cde & 2.86 abcd & 1.64 ab & 1.39 a & 0.51 & *** \\  & Stoneware & 6.22 f & 5.92 f & 5.64 f & 4.68 def & 5.42 ef & 3.68 abc & 1.92 abc & 3.30 bcd & 0.34 & \\ \hline \end{tabular}   
* SEM—standard error of the mean. 2 Sig—significance. Values with different roman letters (a–k) of the same parameter (in rows) indicate statistically significant differences at \(p<0.05\); \(n=5\); \(0.001\)***. Color determination from the lowest (0%) to highest (100%) concentration of parameters. The lowest concentration of a specific parameter in a row is in the darkest red, and the highest content is in the darkestsecretle killer toxins, and resistance to relatively high salinity, high concentrations of lactic acid, and low pH [5]. Representatives of the remaining three yeast species--_D. hansenii, Rh. Mucilaginousa_, and _P. fermentatus_--occurred during the entire fermentation of sauerkraut produced in stoneware vessels, but only in the initial stage (up to the third day) of fermentation in glass jars (Figure 3). The presence of _Rlodototrala_ yeasts during vegetable fermentation is related to the natural reservoir of these microorganisms on the surface of raw vegetables [28]. These are strict aerobes whose development can be significantly limited by the creation of anaerobic conditions [29]. The presence of oxygen in stoneware vessels, also on the final days of fermentation, may enable the proliferation of those microorganisms. This may result in a decrease in the microbiological stability of sauerkraut, causing significant economic losses for producers. The Influence of the Vessel Used for Fermentation on the LAB Content, pH, and Selected Organic Acids Level of Sauerkraut  
In addition to quantitative determinations of the yeast population, lactic acid bacteria were also quantitatively analyzed during sauerkraut fermentation. Before initiating fermentation, the samples contained 3.2 log cfu/g of lactic acid bacteria (Figure 4). Differences in the number of LAB between the vessels used for fermentation were observed after 24 h, and while in stoneware vessels the amount of LAB practically did not change, in glass jars it increased by one order of magnitude.