[Inter-laboratory study for validation of a Japanese official analytical method for determination of patulin in apple juice]. 
To validate a modified version of AOAC official method of analysis 995.10 as an official standard in Japan for determination of patulin in apple juice, an inter-laboratory study was performed in 11 laboratories using a non-contaminated sample, 2 naturally contaminated samples and 2 spiked samples of apple juice.  For naturally contaminated apple juices, the relative standard deviations for repeatability and reproducibility were 3.2, 7.1% and 10.0, 21.7%, respectively.  HORRAT values were 0.4, 0.9.  The average recovery of patulin from spiked sample was 83.7%.  The limit of quantification was calculated as 10 microg/kg.  From these results, the method was thought to be suitable as an official standard for determination of patulin in apple juice in Japan.