STUDY OF BYSSOCHLAMYS FULVA AND CONTROL MEASURES IN PROCESSED FRUITS

Abstract

Summary A survey of various fruit‐producing areas in England showed that fruit and foliage were liable to be contaminated with ascospores of Byssochlamys fulva. Contamination was most pronounced on mummified plums and on certain fruit refuse. The thermal death point of ascospores is about 96°C., but only a small proportion of spores show this maximum heat resistance. Conidia are killed by exposure to relatively low temperatures. The reaction and the sucrose concentration of the heating medium, and the strain of the fungus, are factors influencing the heat resistance of ascospores. Ascospores germinate slowly and irregularly, but their germination is stimulated by previous heating to about 70°C. Ascospore germination and mycelial growth take place at relatively high temperatures, in high sucrose concentrations, in acid media, and in very high concentrations of carbon dioxide. Ascospores are relatively insensitive to antiseptics and to desiccation. Growth is accompanied by the production of a pectin‐destroying enzyme. The results of laboratory experiments were applied to canning experiments and good agreement was obtained. Natural contamination on fruits could be overcome in cans by heating the contents to 195°F. The amount of mycelial growth developing in an infected can depends upon the size of head space and the storage temperature.