Abstract: Fruits and vegetable constitute an important part of human daily diet because they contain some necessary nutritional elements, such as vitamin, mineral salt and plant fiber. Fruits and vegetables are prone to mechanical damage during postharvest operations, which will reduce the eating quality. Meanwhile, both fruits and vegetables can be easily infected with fungi or bacteria (such as late blight, dry rot and soft rot) once they are injured, which in turn can infect normal ones. Bruise damage occurs under the skin of fruits and vegetables without its rupture. Bruised fruits and vegetables are easily confused with normal ones, causing potential economic losses and food safety hazards. Thus, bruise detection has been attracting more and more attention. This paper reviews the mechanism of mechanical damage with respect to consequent physiological and physical changes and the state-of-art progress in the detection of bruise in postharvest fruits and vegetables by taking advantage of optical, thermal, acoustic and electromagnetic properties. Potential difficulties and future research directions are proposed.

Key words: fruit, vegetable, bruise damage, physical properties, non-invasive detection