A fruit tester provides a motor driven intrusive plunger with associated
sensors to determine digital data indicative of plunger position, force
resisting plunger intrusion and constant pressure creep. Sensor data is
presented to a computer for storage, analysis and feedback control of the
plunger. The plunger powering train includes a belt driven ball screw
translator to convert rotary to linear motion and an "S" type stress block
with plural bridge interconnected strain gauges to sense pressure
resisting intrusion to allow accurate measurements. Methods of analysis
are disclosed to determine both resistance to plunger penetration and
plunger creep at fixed pressure, in each of at least two concentric zones
of a fruit, which are related by software for accurate determination of
fruit condition as a function of time, both present and future.