## 3 Results and Discussion
### Microbiological Quality of Bread  
After 7 days of bread storage in Petri dishes at 28 \({}^{\circ}\)C, there was no visual evidence of microbial spoilage. However, after the isolation of yeasts and moulds from the bread, their presence was found in all samples, but their amount was within acceptable standards for bread (Table 4). The highest number of yeast and mould was found in the control, both on the baking day (1.50 \(\times\) 10\({}^{2}\) cfu/g) and after 7 days of storage (2.30 \(\times\) 10\({}^{2}\) cfu/g). Similar numbers of these microorganisms (2.20 \(\times\) 10\({}^{2}\) cfu/g) were found after storage in bread with 15% of the prepared extract. Conversely, the lowest number of yeast and mould on a baking day (1.23 \(\times\) 10\({}^{2}\) cfu/g) as well as after 7 days of storage (1.90 \(\times\) 10\({}^{2}\) cfu/g) was observed in bread in which 10% of the water was replaced with the _Calendula officinalis_ extract.  
One of the difficult challenges facing the bakery industry is to reduce microbial spoilage, especially fungi, thereby extending shelf life and guaranteeing product safety. It has been proven that some plant extracts can inhibit the growth of pathogenic microorganisms  
\begin{table}
\begin{tabular}{c c c} \hline \hline \multirow{2}{*}{**Sample**} & \multicolumn{2}{c}{**Number of Yeasts and Moulds in Bread (cfu/g)**} \\ \cline{2-3}  & **Baking Day** & **After 7 Days of Storage** \\ \hline Control & 1.50 \(\times\) 10\({}^{2}\)\(\pm\) 0.05 a & 2.30 \(\times\) 10\({}^{2}\)\(\pm\) 0.04 a  \\ \hline N10 & 1.23 \(\times\) 10\({}^{2}\)\(\pm\) 0.06 b & 1.90 \(\times\) 10\({}^{2}\)\(\pm\) 0.06 b  \\ \hline N15 & 1.30 \(\times\) 10\({}^{2}\)\(\pm\) 0.03 b & 2.20 \(\times\) 10\({}^{2}\)\(\pm\) 0.05 a  \\ \hline \hline \end{tabular}
\end{table}
Table 4: Number of yeasts and moulds in bread.  
\begin{table}
\begin{tabular}{l c c c} \hline \hline  & \multicolumn{3}{c}{**Sample**} \\ \cline{2-3}  & **Control** & **N10** & **N15** \\ \hline TPC (mg GAE/g DW) & 0.44 \(\pm\) 0.00 b  & 0.78 \(\pm\) 0.01 a  & 0.86 \(\pm\) 0.01 a  \\ \hline DPPH (\%) & 6.87 \(\pm\) 0.01 c  & 8.47 \(\pm\) 0.01 b  & 10.40 \(\pm\) 0.01 a  \\ \hline ABTS (\%) & 20.24 \(\pm\) 0.01 b  & 20.53 \(\pm\) 0.01 b  & 33.59 \(\pm\) 0.02 a  \\ \hline \hline \end{tabular}  
N10, N15—bread, in which 10% and 15% of the water have been replaced with _Calendula officinalis_ water extract, respectively; TPC—total phenolic contents; ABTS—the ability to quench ABTS radicals; DPPH—the ability to quench DPPH radicals; Within each row and for the selected assays, values with the same letter do not differ significantly at \(p<0.05\) ([PERSON]’s post hoc test); mean value (\(n=3\)) \(\pm\) SD.  
\end{table}
Table 3: Phenolics content and antioxidant activity of wheat bread with _Calendula officinalis_ water extract.  
ganisms, so enriching bread is reasonable. [PERSON] et al. [52] found that bread fortified with garlic extract was more microbiologically stable compared to the control, and the addition of the extract inhibited the growth of the fungi _A. flavus_, _Penicillium herquei_, and _F. graminearum_ in the bread. A study by [PERSON] et al. [53] proved that cinnamon (_Cinnamoun verum_) extract improves the shelf life of bread, delays spoilage, and reduces the growth of _Aspergillus_ sp. fungi. Numerous works by other researchers have prompted the search for natural bread additives to extend the shelf life of the finished product. Several reports in the literature about the effectiveness of marigold extract against fungi of the _Aspergillus_ and _Penicillium_ genera [12; 36; 37] pose a threat in baking. The results presented in this paper prove that the appropriate addition of _Calendula officinalis_ water extract can be successfully applied to bread and positively affect the microbiological quality of the product.