Several packs of swollen retailed plain and flavoured yoghurt were examined. The most commonly found species was Pichia anomala, identified both by physiological tests and RFLP analysis of the rDNA internal transcribed spacer (ITS) region. The isolated strains did not ferment lactose and were positive for galactose fermentation, confirming the hypothesis that galactose-fermenting yeast could be the cause of spoilage in yoghurt.