AbstractDegree of whiteness is one of the most important aspects of quality in fresh mushrooms. Tests on the effects of chill storage (1°C) on whiteness of mushrooms showed that both time of putting mushrooms into refrigeration after harvest, and time of removal, had an effect on whiteness both at point of removal and during subsequent storage at ambient temperature. In general, the longer the refrigeration time in a given period of days the whiter the mushrooms. The rate of loss of whiteness at ambient temperature was about the same irrespective of whether mushrooms were stored (1°C) for 0 or 11 days. Mushrooms were placed in six whiteness categories with the aid of a Hunter Colour Difference meter (from excellent L > 93, to very poor L < 69). Mushrooms with L values <80 or <69 were considered as unacceptable from a whiteness point of view at wholesale or consumer levels respectively. These categories confer a degree of objectivity to the results in the chill storage tests.