METHOD TO EVALUATE THE AVERAGE TEMPERATURE AT THE SURFACE OF A HORTICULTURAL CROP

Precooling systems must decrease the temperature of freshly harvested horticultural crops as fast as feasible. A good system provides a unif orm final temperature throughout the mass of produce immediately follo wing treatment. Therefore, the evaluation of precooling systems should include measurements of both the cooling rate and the uniformity of t he temperature within the cooled produce. Cooling rate measures, such as the half-cooling time, have been used to evaluate precooling system s but apply only with a known homogeneous cooling medium temperature. This paper describes an extension of these methods by which the mean t emperature of the medium surrounding the produce is calculated using t he same set of data required to evaluate cooling rates. The theoretica l basis for the method is presented and a laboratory experiment demons trates the technique and its accuracy.