NC samples have been incubated for the same time as contaminated ones. Although the mean values of NC samples
is significantly lower with respect to the mean values of C samples incubated for less than 24h, in Figure 3a it is
evident that all those samples can be considered to be under the detection threshold of the EN (dotted line). All the
samples contaminated can be correctly classified while the minimum detection threshold looks to be around 10
CFU/100ml (Figure 3b) which is compatible with typical contamination values that may occur during actual
production. The plots show that the sensor detection threshold is about 1000 EOS units, corresponding to 8 CFU for
100 ml inoculum of soup. The sensor response also correlates quite well with the inoculum concentration showing a
saturating trend at very high inocula (above 400 CFU per 100ml).