YEAST AND MOLD CONTAMINANTS OF VEGETABLE-OILS

Six vegetable oils were examined for their yeast and mould contaminant s. Sixteen yeasts and 35 mould species were isolated from the oil samp les The isolates were members of the following genera: Saccharomyces, Candida, Debaromyces, Hansenula, Trichosporon, Torulopsis and Pichia f or yeasts and Aspergillus, Fusarium, Penicillium, Mucor, Geotrichum an d Cladosporium for moulds. Amongst the two groups of fungi, Saccharomy ces and Aspergillus species predominated. Examination of the oils for their physico-chemical characteristics revealed that their moisture co ntents were generally below 1%. Palm oil had the highest biochemical o xygen demand (BOD, 2576.88 +/- 12.37 mg/l), while palm kernel oil had the lowest (450.25 +/- 7.42 mg/l). Palm oil had the highest iodine val ue (40.32 +/- 0.27) and coconut oil the lowest (13.18 +/- 0.22). The c umulative maximum growths of the yeast and mould species on the oils w ere used to determine the stabilities of the oils to biodeterioration. Results indicated that palm kernel oil was the most stable to fungal deterioration while palm oil was the least biostable. Copyright (C) 19 96 Elsevier Science Ltd.