Comparison of three selective media for detecting Fusarium species in foods: a collaborative study

At the Second International Workshop on Standardisation of Methods for the Mycological Examination of Foods in Baarn, 1990, three selective media for food-borne Fusarium species were recommended: Czapek-Dox Iprodione Dichloran Agar (CZID), Dichloran Chloramphenicol Peptone agar (DCPA) and Pentachloronitrobenzene Peptone agar (PPA). Lack of sufficient data made it impossible to recommend one Fusarium selective medium. In the present study nine laboratories from seven countries compared CZID, DCPA, and PPA by analysing 10 samples of flour spiked with conidia of Fusarium avenaceum and F. verticillioides (= F. moniliforme). The colony forming units were counted. The total counts on each of the three media were within a similar range for each participant, and no significant differences between the three media were evident. However, the development of Fusarium colonies was quite different on the three media, and most collaborators found it possible to differentiate these Fusarium species by pigmentation on CZID. Pigmentation was much less conspicuous on PPA, and inconspicuous in DCPA cultures. CZID is recommended as the best currently available selective medium for Fusarium isolates from foods.