This is the proceeding of the 5th International Workshop on Food Mycology sponsored by the International Commission on Food Mycology. The workshop took place October 16-18, 2003 in Samso, Denmark. The Fifth Workshop was attended by some 35 participants, drawn from among food mycology and related disciplines around the world. The workshop was highly successful, with papers devoted to media and methods development in food mycology, as is usual with these workshops. Particular emphasis was placed on the fungi which produce mycotoxins, especially their ecology, and through ecology, potential control measures. Sessions were also devoted to yeasts and the inactivation of fungal spores by the use of heat and high pressure. Nearly 40 scientific papers were presented over three days of the workshop, and these papers are the major contributions in these Proceedings.