The ILOS system is based on an analysis of the ethanol dissolved in the juice of apples. To perform the analysis, fruit sampling must be periodically performed inside the cells. Ethanol content is checked using a manual analysis kit that uses an enzyme bio-sensor (disposable) to soak in 0.1 ml of juice with a reagent. The method is quite simple and quick (6-15 min) and a certain number of analyses can be done in succession with the same sensor, before it needs to be replaced.