Fresh raspberries from a plantation are transported over considerable distances. This leads to rapid - though slight - damage to the fruits, the first manifestation of which can be juice seepage. A new method has been developed for the assessment of the mechanical resistance of a mass of raspberry to dynamic damage. The measure was the juice seepage values. The cylinders with samples of 50 fruits were subjected to horizontal vibration at a frequency of 4 Hz and an amplitude of 12 mm for periods of 5, 10, 20, 40 and 60 min. After the vibration, 250 ml of Sorensen buffer was added to the fruit in the cylinders. The quantity of juice in the buffer was determined by means of a spectrophotometric method. The mechanical strength of fruits of six varieties was compared. The determination of the effect of such factors as temperature, ripeness, variety and the duration of vibration on the variability of the juice seepage was made.