## 3 Results and Discussion
### Levels of Viable Microorganisms  
Plate counts of the bacterial groups harbored onto the surfaces of the wooden tables object of investigation are reported in Table 2.  
According to [PERSON]'s test, no statistically significant differences (\(p>0.05\)) between the wooden table biofilms analysed were found for the levels of TMM and all LAB groups. TMM cell densities were higher than 7.0 Log CFU/cm\({}^{2}\) on all four wooden tables investigated. Lower levels of TMM were reported by [PERSON] et al. [15] on the wooden table used for the molding of artisanal Minas cheese made in the Serro and Serra da Canastra regions (4.29 and 4.58 log CFU/cm\({}^{2}\), respectively). In this case, the curd was in contact with the tables for a shorter time compared to the Provola dei Nebrodi curd. All wooden table surfaces displayed high levels of LAB (mesophilic and thermophilic rods and cocci). These findings were somewhat expected considering previous studies focused on wooden vat biofilm characterization [5; 8; 9; 10; 11; 60]. The highest cell densities \begin{table}
\begin{tabular}{c c c c c c} \hline \hline \multirow{2}{*}{**Bacterial Counts**} & \multicolumn{5}{c}{**Samples**} & \multirow{2}{*}{_p_**Value**} \\ \cline{2-2} \cline{4-6}  & **WTA** & **WTB** & **WTC** & **WTD** & **\(p\) Value** \\ \hline TMM & 7.34 \(\pm\) 0.26 & 7.43 \(\pm\) 0.25 & 7.55 \(\pm\) 0.15 & 7.21 \(\pm\) 0.21 & 0.352 \\ Mesophilic rod LAB & 5.36 \(\pm\) 0.16 & 5.82 \(\pm\) 0.21 & 5.57 \(\pm\) 0.23 & 5.55 \(\pm\) 0.21 & 0.128 \\ Thermophilic rod LAB & 5.73 \(\pm\) 0.20 & 5.35 \(\pm\) 0.17 & 5.59 \(\pm\) 0.16 & 5.39 \(\pm\) 0.13 & 0.074 \\ Mesophilic coccus LAB & 7.39 \(\pm\) 0.13 & 7.34 \(\pm\) 0.20 & 7.25 \(\pm\) 0.18 & 7.39 \(\pm\) 0.12 & 0.690 \\ Thermophilic coccus LAB & 5.87 \(\pm\) 0.20 & 5.79 \(\pm\) 0.21 & 5.63 \(\pm\) 0.14 & 5.39 \(\pm\) 0.13 & 0.057 \\ Enterococci & 2.35 \(\pm\) 0.17 C & 2.44 \(\pm\) 0.15 BC & 2.78 \(\pm\) 0.15 AB & 3.05 \(\pm\) 0.17 AB & 0.0024 \\ _Pseudomonas_ & \textless1 B & 2.97 \(\pm\) 0.12 A & \textless1 B & 2.84 \(\pm\) 0.12 A & 0.0001 \\ Enterobacteriaceae & 1.44 \(\pm\) 0.15 D & 3.54 \(\pm\) 0.19 A & \textless 1.87 \(\pm\) 0.12 C & 2.81 \(\pm\) 0.10 B & 0.0001 \\ _E. coli_ & 1.24 \(\pm\) 0.15 C & 3.44 \(\pm\) 0.16 A & \textless1 D & 2.39 \(\pm\) 0.13 B & 0.0001 \\ \hline \hline \end{tabular}  
* Units are log CFU/cm\({}^{2}\) for area samples. Results indicate mean values \(\pm\) standard deviation (SD) of n = 8 plate counts (carried out in duplicates for two independent sampling). Abbreviation: WT, wooden table; A–D, dairy factory A–dairy factory D; TMM, total mesophilic microorganisms; LAB, lactic acid bacteria; _E. Escherichia_. On the row A, B, C, D: \(p<0.01\).  
\end{table} 
Table 2: Microbial load 1 of the biofilms of the wooden tables used for curd acidification during PDO Provola dei Nebrodi cheese production. for mesophilic LAB cocci. The levels of this LAB group were superimposable to those of TMM indicating that these bacteria dominated all wooden table biofilms. The dominance of cocci over rods was previously reported in wooden vats used for the production of PDO bovine [9; 10; 11] and ovine [11; 12; 61] cheeses. Enterococci were detected in all wooden table samples in the range 2.35-3.05 Log CFU/cm\({}^{2}\). Similar levels of enterococci were found on the surfaces of the wooden vats used for making Caciocavallo Palermitano and PDO Vastedda della valle del Belice cheeses [11] and on wooden shelves used in the ripening of a traditional French raw milk smear cheese [14]. However, high throughput analysis detected _Enterococcus_ only in WTA and WTD biofilms, probably because _Enterococcus_ were part of the unassigned OTUs of total bacterial community or they were below 0.1% of abundance or their DNAs were rendered inaccessible by nucleases. Regarding _Pseudomonas_ spp., known agents of food spoilage [62], only the samples WTB and WTD were characterized by the presence of these bacteria with concentrations of about 3 Log CFU/cm\({}^{2}\). Generally _Pseudomonas_ spp.