Reduction of patulin in apple juice samples — influence of initial processing

Abstract

Patulin is a secondary metabolite produced by a wide range of fungi including Penicillium expansum, a common contaminant of apples. Patulin is reputed to be a mutagen and recommendations have been made that levels should not exceed 50 nglg in apple juice intended for human consumption. The production of apple juice requires the use of ripe fruit, which may be pre-disposed to fungal contamination with P. expansum and concurrent contamination with patulin. During a study using selected over-ripe fruit, triplicate samples of apples were withdrawn at several points prior to maceration. The mean patulin level in the non-processed fruit was found to be 920 nglg, but this level dropped to 190 nglg following an initial water treatment step. Analyses of the wash water showed that appreciable levels had been transferred from the solid to the aqueous phase. Additional removal, by hand, of rotten and damaged fruit prior to further processing, significantly reduced the mean patulin level in the juice to 55 nglg. High patulin levels were recorded in the rotten fractions (mean = 2335 nglg). Mycological analyses tended to support the chemical data, in that removal of the rotten fruit significantly reduced the total fungal counts in the juice samples.