## 3 Results
### Microbiological Analyses
\begin{table}
\begin{tabular}{c c c c c c} \hline \hline
**Parameter** & **Sample** & **T0 (Day 1)** & **T1 (Day 15)** & **T2 (Day 25)** & **T3 (Day 30)** \\ \hline \multirow{4}{*}{_TAB 30 \({}^{\circ}\)C_} & MTS1 & 1.96 & 5.49 & 5.70 & 6.46 \\  & MTS2 & 1.96 & 4.10 & 3.96 & 5.94 \\  & MTS3 & 3.96 & 2.48 & 4.73 & 5.65 \\  & MTC & 2.83 & 3.31 & 3.89 & 4.02 \\ \hline \multirow{4}{*}{_Enterobacteriaceae_} & MTS1 & \textless{}1 & \textless{}1 & \textless{}1 & \textless{}1 \\  & MTS2 & \textless{}1 & \textless{}1 & \textless{}1 & \textless{}1 \\  & MTS3 & \textless{}1 & \textless{}1 & \textless{}1 & \textless{}1 \\  & MTC & \textless{}1 & \textless{}1 & \textless{}1 & \textless{}1 \\ \hline \multirow{4}{*}{\(\beta\)-Glucuronidase-positive E. coli} & MTS1 & \textless{}1 & \textless{}1 & \textless{}1 & \\  & MTS2 & \textless{}1 & \textless{}1 & \textless{}1 & \\  & MTS3 & \textless{}1 & \textless{}1 & \textless{}1 & \\  & MTC & \textless{}1 & \textless{}1 & \textless{}1 & \\ \hline \multirow{4}{*}{_Coagulase-positive_} & MTS1 & \textless{}2 & 3.07 & 5.70 & 3.49 \\  & MTS2 & \textless{}2 & 2.56 & 3.95 & 3.47 \\  & \textless{}3 & 3.96 & \textless{}2 & 2.65 & 4.8 \\  & MTC & \textless{}2 & \textless{}2 & \textless{}2 & \textless{}2 \\ \hline \multirow{4}{*}{_Sulfite-reducing Clostridia_} & MTS1 & \textless{}2 & \textless{}2 & \textless{}2 & \\  & MTS2 & \textless{}2 & \textless{}2 & \textless{}2 & \\  & MTS3 & \textless{}2 & \textless{}2 & \textless{}2 & \\  & MTC & \textless{}2 & \textless{}2 & \textless{}2 & \\ \hline \multirow{4}{*}{_Campylobacter_ spp.} & MTS1 & \textless{}2 & \textless{}2 & \textless{}2 & \\  & MTS2 & \textless{}2 & \textless{}2 & \textless{}2 & \\  & MTS3 & \textless{}2 & \textless{}2 & \textless{}2 & \\  & MTC & \textless{}2 & \textless{}2 & \textless{}2 & \\ \hline \multirow{4}{*}{_B. cereus_} & MTS1 & \textless{}2 & \textless{}2 & 2.91 & \\  & MTS2 & \textless{}2 & \textless{}2 & \textless{}2 & \\  & MTS3 & \textless{}2 & \textless{}2 & \textless{}2 & \\  & MTC & \textless{}2 & \textless{}2 & \textless{}2 & \\ \hline \multirow{4}{*}{_Listeria monocytogenes_} & MTS1 & \textless{}2 & \textless{}2 & \textless{}2 & 2.25 \\  & MTS2 & \textless{}2 & \textless{}2 & \textless{}2 & \textless{}2 \\ \cline{1-1}  & MTS3 & \textless{}2 & \textless{}2 & \textless{}2 & \textless{}2 \\ \cline{1-1}  & MTC & \textless{}2 & \textless{}2 & \textless{}2 & \textless{}2 \\ \hline \hline \end{tabular}  
* The results are expressed as Log (CFU/g) values. MTS1 = mandarin peel, MTS2 = common lambsquarters, MTS3 = oregano, and MTC = sodium nitrite.  
\end{table} 
Table 3: Microbiogical trends of the four mortadella formulations (three experimental (MTS1, MTS2, and MTS3) and one control (MTC)) during the storage period. again, it is plausible that contamination occurred during the packaging process of the product. However, despite there being evident contamination, the oregano and especially the common lambsquarters used as natural antimicrobial agents demonstrated their ability to reduce microbial growth, effectively being able to maintain microbial loads between 2 and 3 Log (CFU/g) over time (except for the oregano at the final stage (T3)). Conversely, the mandarin peel powder did not exhibit comparable efficacy, as highlighted by a staphylococcal concentration of 5.70 Log (CFU/g) detected in the MTS1 sample at T2, exceeding the acceptability limits established by regulation EC No. 2073/2005 [53]. As regards pathogenic microorganisms, no sulfite-reducing clostridia or _Campylobacter_ spp. were detected in any of the analyzed samples, with concentrations remaining always below 2 Log (CFU/g), which represents the detection limit of the ISO methods. Similarly, all the samples tested negative for _Salmonella_. Conversely, _Bacillus cereus_ and _Listeria monocytogenes_ were detected at two different sampling times (T2 and T3, respectively) in the same sample (MTS1). However, the ISO method provides only presumptive positive results, as colonies with characteristic appearances are considered as significant and counted.