## 4 Conclusions
\begin{table}
\begin{tabular}{c c c c c c c} \hline \hline
**Mixture [Volume in Bottle]** &
\begin{tabular}{c} **\#PLS** \\ **Factors** \\ \end{tabular} & \(\mathbf{R^{2}}\) & \(\mathbf{Q^{2}}\) & **RMSEC** & **RMSEP** & **LOD (\%)** \\ \hline Sunflower O in EVOO: 0–90\% EVOO [90 mL in bottle] & 6 & 0.99 & 0.98 & 2.51 & 3.27 & 8.59 \\ Sunflower O in EVOO: 10–90\% EVOO [28 mL in bottle] & 6 & 1.00 & 1.00 & 1.01 & 1.37 & 2.24 \\ Pomaace OO in EVOO: 0–90\% EVOO [28 mL in bottle] & 4 & 0.97 & 0.97 & 4.68 & 4.91 & 10.64 \\ Refined OO in EVOO: 0–90\% EVOO [28 mL in bottle] & 6 & 0.92 & 0.84 & 7.37 & 10.15 & 13.60 \\ \hline \hline \end{tabular}  
* The spectral range for all analyses was 596–1420 cm\({}^{-1}\). Standard normal variate (SNV) was used to pre-process the data. #PLS factors represents the number of latent variables used in each PLSR model. \(R^{2}\) and \(Q^{2}\) represent the goodness of the model’s fit to the dataset for the 1000 training sets and the 1000 test sets, respectively. RMSEC and RMSEP denote root mean squared error results pertaining to the training sets and test sets, respectively. LOD is the limit of detection calculated from the PLSR models.  
\end{table} 
Table 2: PLSR results for the bootstrap models of the adulterated oils in EVOO using SORS for through-container analysis. We believe that in the future, working with regulatory authorities, these field portable point-and-shoot methods can be used onsite from farm to fork in olive oil production facilities, supply depots, as well as in retail settings. This is especially the case for SORS, which we have shown for the first time provides exciting potential for through-container rapid screening, with the PLSR modelling providing results in accordance with international validation guidelines [50]. The following are available online at [[https://www.mdpi.com/article/10.3390/app11188347/s1](https://www.mdpi.com/article/10.3390/app11188347/s1)]([https://www.mdpi.com/article/10.3390/app11188347/s1](https://www.mdpi.com/article/10.3390/app11188347/s1)), Table S1: Sample preparation for SORS, Figure S1: Pictures of the [PERSON] constructed wooden holder with a Resolve and commercially available clear glass bottle in situ, Figure S2: Conventional Raman spectra of olive oil and the adulterants, Figure S3: Raman and SORS spectra showing the adulteration of authentic EVOO with sunflower oil, Figure S4: PCA loadings plots on Raman spectral data collected showing the adulteration of authentic EVOO with sunflower oil, Figure S5: PCA scores plots on Raman spectral data collected showing the adulteration of authentic EVOO with sunflower oil, Figure S6: PCA scores plots on Raman spectral data collected showing the adulteration of authentic EVOO with pomace olive oil, Figure S7: PCA scores plots on Raman spectral data collected showing the adulteration of authentic EVOO with refined olive oil, Figure S8: PLSR prediction model plots comparing the predicted actual concentrations for the sunflower oil against the known level of this adulterant in EVOO, Figure S9: PLSR prediction model plots comparing the predicted actual concentrations for the pomace olive oil against the known level of this adulterant in EVOO. Conceptualisation, N.B., D.I.E., P.M. and R.G. ; Formal analysis, M.V., H.M, Y.X. and P.I.C.R. ; Methodology, M.V. ; Resources, R.G. ; Software, Y.X., P.I.C.R. and P.M.; Supervision, R.G. ; Validation, R.G. ; Writing--original draft, M.V., H.M. and R.G. ; Writing--review & editing, All. All authors have read and agreed to the published version of the manuscript. Science and Technology Facilities Council (STFC) Food Security Network+ (No. ST/T002921/1; [[https://www.stfcfoodnetwork.org/](https://www.stfcfoodnetwork.org/)]([https://www.stfcfoodnetwork.org/](https://www.stfcfoodnetwork.org/)) (accessed on 4 September 2021)). Daphre Jackson Fellowship funded by the University of Liverpool and UK BBSRC. Not required. On request to authors. R.G.