## 3 Results and Discussion  
In this study, a \"mato\" fresh cheese was selected, since the pH and a\({}_{\mathrm{w}}\) values, together with its low content of NaCl (0.1%) and the absence of other antimicrobial preservatives, make this cheese suitable for _B. cereus_ growth. In this sense, the composition and volume of the medium used to dissolve the crude extract and non-polar subfraction were carefully selected to have a minimal effect on the a\({}_{\mathrm{w}}\) (0.989 \(\pm\) 0.002) and pH (6.76 \(\pm\) 0.02) values of \"mato\" cheese under experimental conditions. _B. cereus_ vegetative cells were inoculated in \"mato\" cheese in order to simulate natural germination of spores that survive milk pasteurization, post-contamination after milk pasteurization, or during cheese manufacturing. Total aerobic microorganisms and _Enterobacteriaceae_ counts were under the limit of detection in control samples (<10 cfu/g and <100 cfu/g, respectively) and no colonies were counted in control samples without pathogen inoculation nor addition of extract during the storage time, indicating the microbiological hygienic quality of the product and proper handling conditions during the experiment. Counts of the control samples were kept at the initial level throughout storage since the selected _B. cereus_ strain was a mesophile and, therefore, not able to grow under refrigerated conditions at 8 \({}^{\circ}\)C. However, counts for control of mid-polar subfraction diminished significatively (_p_ < 0.05) at the end of the storage time, accounting for a 1.76 log reduction. Compared to control cheeses, _B. cereus_ counts decreased to a higher extent in fresh cheeses with _E. seleniginoides_ crude extract and the respective subfractions over the storage time (Table 1), although the inactivation rate and the magnitude of the count reduction were dependent on the extract and the concentration applied. A significative immediate bactericidal effect (_p_ < 0.05), registered after two hours of inoculation (t\({}_{0}\)) compared with initial counts in controls, was only observed at the highest concentration of the non-polar subfraction, with a reduction of 2.24 \(\pm\) 0.61 log. In the presence of the crude extract, the total inactivation observed accounted for almost a 2 log reduction (1.81 \(\pm\) 0.11 log) with the lowest concentration (14 mg/g), and the effect was similar with the intermediate (28 mg/g) and highest (70 mg/g) concentrations where the log reduction doubled, reaching 4 log. However, the effect in the presence of the highest concentration was variable between batches, whereas counts diminished quickly under the limit of detection by plate counting (<0.6 log cfu/g) after 2 days in batch 2, with an almost 3 log reduction (to 2.76 log cfu/g) observed in batch 1 and residual counts of 1.77 log remained in fresh cheese after 10 days of storage (Figure 1). \begin{table}
\begin{tabular}{c c c c} \hline  & \multicolumn{3}{c}{**Crude extract**} \\ \hline  & **14 mg/g** & **28 mg/g** & **70 mg/g** \\ \cline{2-4}
**Initial log reduction a** & \textless{}0.5 & \textless{}0.5 & 0.92 \(\pm\) 0.27 \\
**Inactivation potential b** & 1.81 \(\pm\) 0.11 & 4.05 \(\pm\) 0.45 & 4.06 \(\pm\) 1.84 \\ \hline  & \multicolumn{3}{c}{**Non-polar subfraction**} \\ \hline  & **5 mg/g** & **10 mg/g** & **20 mg/g** \\ \cline{2-4}
**Initial log reduction a** & \textless{}0.5 & \textless{}0.5 & 2.24 \(\pm\) 0.61 \\
**Inactivation potential b** & 4.70 \(\pm\) 0.83 & 4.70 \(\pm\) 0.83 & 4.70 \(\pm\) 0.83 \\ \hline  & \multicolumn{3}{c}{**Mid-polar subfraction**} \\ \hline  & **10 mg/g** & **25 mg/g** & **50 mg/g** \\ \cline{2-4}
**Initial log reduction a** & \textless{}0.5 & \textless{}0.5 & 0.91 \(\pm\) 0.04 \\
**Inactivation potential b** & 1.76 \(\pm\) 1.20 & 4.53 \(\pm\) 1.19 & 4.53 \(\pm\) 1.19 \\ \hline \end{tabular}  
* Immediate bactericidal effect after 2 h of inoculation. b Total log reduction after 10 days storage at 8 \({}^{\circ}\)C.  
\end{table} 
Table 1: Log reduction in _B.