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Ergosterol (ERG) is a sterol produced by most fungi, but not by most plants. Thus, measurement of ERG in cereals makes it possible to determine the presence of fungi in cereals that can cause quality problems, such as mycotoxin contamination. This study developed and performed a single-laboratory validation for a method to test for ERG in various cereals. ERG was extracted by refluxing samples for 1 h with methanol-sodium hydroxide. ERG was extracted from the extract with hexane and then purified using a silica gel cartridge column. ERG was then separated and detected by reverse-phase high-performance liquid chromatography (HPLC). 'Within-day' recoveries of ERG at low levels were 92-99% with relative standard deviations (RSDs) of 3.2-6.5%. 'Between-day' recoveries of ERG at low levels were 97% and RSDs were 4.2-10.2%, respectively. Average recoveries of ERG over the range from 1.0 to 100.0 mg kg(-1) were 81-105% and RSDs were 3.9-16.3%.

Introduction Ochratoxin A (OA) is a mycotoxin which is produced by some Aspergillus and Penicillium fungi. Ochratoxin A is nephrotoxic as well as carcinogenic 1) , and is often found in cereals, coffee, wine and animal products 2, 3). Thus, the prevention of OA contamination of agricultural products is an important health concern 4). Because of its widespread distribution and toxicity, the regulation in EU for OA contamination of foodstuffs has become very strict 5) , requiring sensitive and accurate analytical methods. Current methods for ochatoxins use either an immunoaffinity column 6) or a multifunctional clean up column 7) as a clean up process before the definitive HPLC analysis of ochratoxins. However, only limited information for OA contamination on rice, a staple food for most Asian countries, is available because of the lack of validation of methods in this food crop. To validate a method, a full collaborative validation process such as the AOAC-OMA 8) is well known, although this

Patulin contamination is known in various fruit products, including apple products. In this study, a solid phase extraction clean-up method was developed and validated for patulin in various fruit juices. Patulin was extracted from samples with ethyl acetate and then diluted with hexane. Patulin was isolated with a silica gel cartridge column, then analysed by reverse phase liquid chromatography with UV detection. The detection and quantitation limits were 0.06 and 0.15 ng, respectively. Recoveries within a day, and between days, were determined. Within day recoveries of patulin (n=6) at 5.0 and 50.0 µg/kg were 96-105% and 89-95%, respectively, with relative standard deviations (RSD) of 2.4-6.9 and 0.7-1.7%, respectively. Between day recoveries at 5.0 and 50.0 µg/kg were 96-108% and 92-94%, respectively, with RSDs of 7.1-12.1 and 2.3-4.1%, respectively. Average recoveries of patulin in the range from 2.0 to 80.0 µg/kg were 114 to 93%.