THE NORMAL MYCOFLORA OF COMMODITIES FROM THAILAND .1. NUTS AND OILSEEDS

A comprehensive study was carried out of the fungi occurring in commod ities normally traded in Thailand. Samples of major commodities were o btained from farmers' stocks and middlemen in major producing areas th roughout the country. Retail samples were obtained from outlets in and around Bangkok. Samples were divided into two portions, one being exa mined in Bangkok, and the second in Sydney. After surface disinfection , fungi were enumerated by direct plating on dichloran rose bengal chl oramphenicol agar, dichloran 18% glycerol agar, Aspergillus flavus and parasiticus agar and dichloran chloramphenicol peptone agar. Figures for percentage infection were calculated, and fungi were isolated and identified to species' level. In all 602 samples were examined, and at North Ryde about 18000 fungal isolates identified. Data obtained from 329 samples are reported here, comprising maize (154), peanuts (109), cashews (45) and copra (21). Major fungi in maize included Fusarium m oniliforme (present in 97% of samples), Aspergillus flavus (85%), Peni cillium citrinum (67%), Aspergillus niger (64%), Lasiodiplodia theobro mae (58%) and Fusarium semitectum (45%). In peanuts, the major fungi w ere Aspergillus flavus (95% of samples), Aspergillus niger (86%), Rhiz opus oryzae (60%), Eurotium rubrum (51%), Macrophomina phaseolina (49% ), Penicillium citrinum (46%) and Eurotium chevalieri (46%). Invasion in cashews was lower, major fungi being Aspergillus flavus (60%), Nigr ospora oryzae (58%), Aspergillus niger (53%), Chaetomium globosum (47% ) and Eurotium chevalieri (40%). Aspergillus flavus (86% of samples) w as again dominant in copra, with Rhizopus oryzae (52%), Aspergillus ni ger (43%), Eurotium chevalieri (43%) the only other species exceeding 40% infection. Aspergillus parasiticus was rarely seen, and Aspergillu s nomius was reported from foods for the first time.