A European Project entitled 'Quality of fruits: Engineering research for improving the quality preservation during pre- and postharvest operations' is being carried out by six European research Institutions. Relevant aspects of quality of fresh fruit in the European market are investigated. Firmness sensing of selected varieties of apples, pears and avocado fruits has been developed using a non-destructive impact technique. In addition to firmness measurements, postharvest ripeness of apples and pears was monitored by spectrophotometric reflectance measurements, and that of avocadoes by Hunter colour measurements. The data obtained from firmness sensing were analysed by three analytical procedures: Principal Components, Correlation, and Stepwise Discriminant Analysis. A new software was developed to control the impact test, analyse the data, and sort the fruit into specified classes, based on the criteria obtained from a training run. Similar procedures were used to analyse the reflectance and colour data. Both sensing systems were able to classify fruits with good accuracy. An automatized prototype of on-line classifier has been built.