Figure 1: Comparison of different proton spectra of 5 selected infected samples. A) The overview of the superimposed spectra shows several regions in which the samples differ a lot. Those regions were excluded in the following PCA analysis. B) The glucose region of the spectra shows the dramatic effect of this signal on the overall aspect of the spectra. Based on this signals the spectra were classified, and the results are shown color-coded: red and yellow are good spectra, green is the limit for classification. Blue and violet can not be used, and later the PCA models classify them as out of the model.