Possibilities and limits of the use of thermography for the examination of horticultural products.

flection of the complex superposition of heatand mass transfer processes between the produce and the environment. Thermography is a common method of measuring temperature distributions, i.e. local temperature differences at the produce surface. More than 40 years have passed since thermography was first applied for plant examination [1, 2]. Due to sinking prices and improved operability, thermo-graphy has developed into an important tool in engineering, medical research, and other fields, especially during the past 10 years. A larger number of studies is known in which examinations of plants using thermal imaging are described. Infrared image analysis has been employed for the determination of physiological disruptions in harvested plants [3], the transpiration behaviour of intact plants at the preAs a result of complicated heatand substance exchange processes between the produce and the environment after harvest, the temperature on the surface of fruit and vegetables is generally lower than the air temperature. Infrared thermography systems allow the distribution of these surface temperatures to be measured. Temperature differences are made visible in the form of colour differences and evaluated with methods of computer image analysis. The present contribution shows the possibilities and limits of the use of thermal imaging systems for examinations of quality changes of horticultural produce at the postharvest stage. In principle, such thermal imaging systems are able to measure produce properties connected with thermal processes (transpiration, respiration). They may lead to qualitatively new insights and thus make a contribution towards quality maintenance. When interpreting the results, the interrelation between the produce and its environment must always be taken into account.