Mechanical handling of fruits from harvesting to marketing has often led to excessive bruises such that few of them make it to the fresh market. This has, therefore, called for a new engineering approach to determine the parameters which influence the firmness of fruits in order to reflect the optimum maturity for mechanical harvesting and post harvest handling. This paper reviews both the destructive and non-destructive techniques for determination of mechanical properties that influence the firmness of fruits. Mathematical equations relating fruit parameters like the Modulus of Elasticity, Poisson's ratio, bruise volumes, impact forces, energy absorbed by the fruit, fruit deformation and contact stresses are presented. Also, recent techniques used in mechanical handling of fruits to minimize bruises are addressed.