CHRYSOSPORIUM SPECIES, POTENTIAL SPOILAGE ORGANISMS OF CHOCOLATE

Standard methods of analysing foods for the presence of moulds are ina dequate for the detection of genera such as Chrysosporium which do not grow at the high water activities of most mycological media. The use of malt, yeast, 50% glucose agar (MY50G) in sealed containers as an en richment medium allowed time for germination and growth of heat-stress ed spores. Three Chrysosporium spp., C. xerophilum Pitt, C., inops (Ca rmichael) and C., farinicola (Burnside) Skou, were isolated from comme rcial chocolate bars with a water activity (a(w)) of approximately 0.2 8. Chrysosporium inops was isolated from commercial milk crumb and a n ew Chrysosporium sp. was isolated from Ghanaian cocoa beans. In chocol ates made by coating MY50G agar (a(w) = 0.89) with chocolate (a(w) = 0 .27) containing C. inops arthroconidia, two types of deterioration wer e seen after storage. The first was fat bloom due to recrystallization of the cocoa butter on the outer and inner chocolate surface. The sec ond was growth of C. inops which occurred on the inside chocolate surf ace adjacent to the MY50G agar filling and on the outside surface afte r holding at 92% equilibrium relative humidity (erh) for 12 d. There w as some evidence that C. inops could grow on the outside of chocolates held at 5.7% erh after 4 months' storage at 25 degrees C. The appeara nce of the white fungal growth was not unlike fat bloom to the naked e ye but was clearly different with the electron microscope.