## 3 Results
### Performance of v-ddPCR on Routine and Retail Samples  
The quantification of target DNA in ddPCR (copy number concentration) is based on an absolute count of PCR positive droplets (with PCR amplification of the target gene) and PCR negative droplets (without PCR amplification of the target gene). As advised in [PERSON] [43] and the Digital MIQE Guidelines [37; 44], quality controls were integrated in each ddPCR run and checked before subsequent analysis of samples results. A no template control (NTC) serves as a control for extraneous nucleic acid contamination of this PCR, and it monitor false-positive reactions; the extraction control (EC) excludes contamination during DNA extraction; and internal amplification control (IAC with 50 copies/\(\upmu\)L) helps to detect PCR inhibitors co-isolated from the matrix, and it confirms the negative results of the sample. Moreover, positive controls with specific target DNA of reference strains  
\begin{table}
\begin{tabular}{c c c c c c c c c c c} \hline \hline \begin{tabular}{c} **Living** \\ **Cells/mL** \\ **Nominal** \\ **Value** \\ \end{tabular} & **Day** & **Cartridge** & \begin{tabular}{c} **Time Interval:** \\ **Extraction to** \\ **Droplet** \\ **Generation** \\ \end{tabular} & \begin{tabular}{c} **Factorial** \\ **Effects** \\ **Construction** \\ \end{tabular} & \begin{tabular}{c} **Recovery** \\ **Correction** \\ \end{tabular} & \begin{tabular}{c} **Repeat-** \\ **Ability** \\ \end{tabular} & **Run** & \
\begin{tabular}{c} **Binomial** \\ **(Poisson)** \\ \end{tabular} & **Total** &
\begin{tabular}{c} **Total** \\ **Minus** \\ **Binomial** \\ \end{tabular} \\ \hline
200 & 38.2\% & 6.9\% & 11.4\% & 41.2\% & 17.8\% & 25.2\% & 0.0\% & 55.1\% & 75.4\% & 51.5\% \\ \hline
500 & 29.5\% & 5.3\% & 11.4\% & 32.6\% & 12.6\% & 19.7\% & 0.0\% & 34.8\% & 53.1\% & 40.1\% \\ \hline
1000 & 23.6\% & 4.1\% & 11.4\% & 26.9\% & 9.0\% & 15.8\% & 0.0\% & 24.5\% & 40.7\% & 32.5\% \\ \hline
5000 & 13.7\% & 1.5\% & 11.4\% & 18.1\% & 5.5\% & 8.9\% & 0.0\% & 11.4\% & 23.8\% & 20.9\% \\ \hline
10,000 & 12.4\% & 1.0\% & 11.4\% & 17.0\% & 7.8\% & 7.9\% & 0.0\% & 8.6\% & 22.1\% & 20.3\% \\ \hline \hline \end{tabular}
\end{table}
Table 10: Calculated RSD value for the technical uncertainty components—Supermix with dUTP.  
\begin{table}
\begin{tabular}{c c c c c c c c c} \hline \hline \begin{tabular}{c} **Living** \\ **Cells/mL** \\ **Nominal** \\ **Value** \\ \end{tabular} & **Day** & **Cartridge** & \begin{tabular}{c} **Time Interval:** \\ **Extraction to** \\ **Droplet** \\ **Generation** \\ \end{tabular} & \begin{tabular}{c} **Factorial** \\ **Effects** \\ **Effects** \\ **Construction** \\ \end{tabular} & \begin{tabular}{c} **Recovery** \\ **Correction** \\ \end{tabular} & \begin{tabular}{c} **Repeat-** \\ **Ability** \\ \end{tabular} & **Run** & \
\begin{tabular}{c} **Binomial** \\ **(Poisson)** \\ \end{tabular} & **Total** &
\begin{tabular}{c} **Total** \\ **Minus** \\ **Binomial** \\ \end{tabular} \\ \hline
200 & 38.2\% & 6.9\% & 11.4\% & 41.2\% & 17.8\% & 25.2\% & 0.0\% & 55.1\% & 75.4\% & 51.5\% \\ \hline
500 & 29.5\% & 5.3\% & 11.4\% & 32.6\% & 12.6\% & 19.7\% & 0.0\% & 34.8\% & 53.1\% & 40.1\% \\ \hline
1000 & 23.6\%C. jejuni and C. coli_ (10 \(\rm{pg/\mu L}\)\(\equiv\) 9000-13,000 \(\rm{cp/\mu L}\)) allow for checking if the ddPCR worked correctly. Finally, a low number of droplets measured (<10,000 cp per 20 \(\rm{\mu L}\) PCR) as well as the lack of negative droplets are also criteria to exclude subsequent analysis of samples results.