## 4 Discussion  
The results denote a level of contamination of the carcasses higher than that set by EU legislation as process hygiene criteria for pig slaughtering [24]. The results are even higher than those reported from pig carcasses by the ECDC and EFSA (3.88%) [1] but are in line \begin{table}
\begin{tabular}{c c c c c} \hline \hline  & **Overall** & \multicolumn{2}{c}{**Season**} & \multicolumn{2}{c}{**Slaughterhouse Capacity**} \\ \cline{3-5} _Salmonella_ & & **Spring/Summer** & **Autumn/Winter** & **\textless{}5000** & **5000–50,000** \\
**Serovars** & **(\%)** & **(\%)** & **Animals/Year** & **Animals/Year** \\  & **(\(n\) = 45)** & **(\(n\) = 25)** & **(\(n\) = 20)** & **(\(n\) = 8)** & **(\(n\) = 37)** \\ \hline
4,[5],12:i- & 33.33 & 36.00 & 30.00 & 50.00 & 29.73 \\ Derby & 40.00 & 44.00 & 35.00 & 25.00 & 43.24 \\ Infantis & 2.22 & 0.00 & 5.00 & 0.00 & 2.70 \\ Bredeney & 4.44 & 4.00 & 5.00 & 0.00 & 5.41 \\ Typhimurium & 2.22 & 4.00 & 0.00 & 12.50 & 0.00 \\ Give & 2.22 & 0.00 & 5.00 & 12.50 & 0.00 \\ London & 4.44 & 0.00 & 10.00 & 0.00 & 5.41 \\ Rissen & 6.67 & 4.00 & 10.00 & 0.00 & 8.11 \\ Brandeburg & 2.22 & 4.00 & 0.00 & 0.00 & 2.70 \\ Goldcoast & 2.22 & 4.00 & 0.00 & 0.00 & 2.70 \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Percentage of _Salmonella_ serotypes isolated from pig carcasses according to season and slaughterhouse capacity. \begin{table}
\begin{tabular}{c c c c} \hline \hline \multirow{2}{*}{_Salmonella_ **Serovars**} & **2017** & **2018** & **2019** \\  & **(\%)** & **(\%)** & **(\%)** \\  & **(\(n\) = 8)** & **(\(n\) = 21)** & **(\(n\) = 16)** \\ \hline
4,[5],12:i- & 50.00 & 23.80 & 37.50 \\ Derby & 37.50 & 57.10 & 18.80 \\ Infants & 12.50 & 0.00 & 0.00 \\ Bredeney & 0.00 & 9.50 & 0.00 \\ Typhimuriumurium & 0.00 & 4.80 & 0.00 \\ Give & 0.00 & 4.80 & 0.00 \\ London & 0.00 & 0.00 & 12.50 \\ Rissen & 0.00 & 0.00 & 18.80 \\ Brandeburg & 0.00 & 0.00 & 6.30 \\ Goldcoast & 0.00 & 0.00 & 6.30 \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Percentage of _Salmonella_ serotypes isolated from pig carcasses according to the year of sampling. with results obtained by other authors in extra-EU, EU, and Italian abattoirs [14; 22; 32; 33; 34; 35]. Nonetheless, where specific national guarantee plans are in force, including monitoring at the farm level (e.g., in Finland, Denmark, and Sweden) [19], the _Salmonella_ prevalence drops to near zero [1]. When a high prevalence is detected by CA at a slaughterhouse, some concerns have to be considered. Even if the literature reports that the chilling of the carcass could decrease the level of _Salmonella_-positive samples [15], the higher the prevalence in the carcass, the more likely the presence of _Salmonella_ after chilling [36], with a possible safety impact on the subsequent steps of the meat chain. In this context, the absence of _Salmonella_ in the final products at the market level, as set by the EU legislation [24], may not be achieved, and the risk to consumers increases. Nonetheless, the results consequent to the official control were sent each year to the FBOs to implement corrective action at the abattoirs, even if self-monitoring analyses always reveal compliance with the process hygiene criteria (<6% of positive carcass samples; data not shown). This discrepancy between the official results and FBOs' self-monitoring results is also stressed by ECDC EFSA reports and needs further investigation [1]. Despite the efforts and proper hygiene practices implemented at the selected abattoirs, inconclusive results were obtained in these three years. Moreover, the presence of a similar prevalence in small and medium-sized abattoirs, where a different approach to slaughtering procedures and HACCP implementation could affect the contamination level [22], brings the core of the problem back on the farm and the pre-slaughter level [13; 22].