Patulin determination in apples with rotten areas

Abstract

Patulin is a mycotoxin produced by Penicillium and Aspergillus species, and in particular by P. expansum in apple-rotting fungus. In this work, we evaluated the patulin content in apples with rotten areas of different sizes (with green and/or blue moulds), and we studied the diffusion behaviour of patulin into unspoiled areas of the apples. An analytical procedure based on high-performance liquid chromatography with UV detection was used to analyse 35 apples with rotten areas. Separations were performed on a 250x4.6 mm i.d. C(18) analytical column of 5 mu m diameter. Acetonitrile/water (5:95) was used as the mobile phase at a flow rate of 1.5 ml/min and the elution was monitored by UV absorption at 275 nm, performed at 40 degrees C. The detection limit by HPLC-UV detector for pure standard was 6.7 ng/ml and the quantification limit was 0.03 mu g/ml. The affected areas represented different percentages of the total weight of the whole apple and ranged from 2.5 to 52.3%. Three apples had patulin concentrations below the limit of detection; the remaining 32 apples had varying patulin levels (from 1.01 to 120.40 mg/kg). To evaluate if the mycotoxin could migrate to the areas not yet affected by rot, we analysed the unspoiled portion of each apple, showing 1.91 mu g/kg as the median concentration of patulin and the highest value of 5,020 mu g/kg; these results confirmed that patulin could migrate through apple tissue that has not yet been spoiled.