3.4. Determination of sensitivity
The sensitivity of this method was assessed by detecting signal to noise ratio (S/N) of indicator volatile compounds of the samples that had the lowest degree of infestation. In 1 kg of feed, a single male insect was chosen to be the lowest sensitivity to be tested in this experiment. Infestation with five and fifteen of mixed gender insects and control (non-infested samples) were also prepared for the case that a single beetle could not be detected. In the case that fifteen insects could not be detected, the samples with more insects (twenty, twenty-five and thirty beetles) were prepared and extracted by the same method.