title: Ochratoxin A in cocoa and chocolate sampled in Canada.
abstract: In order to determine the levels of ochratoxin A (OTA) in cocoa and cocoa products available in Canada, a previously published analytical method, with minor modifications to the extraction and immunoaffinity clean-up and inclusion of an evaporation step, was initially used (Method I). To improve the low method recoveries (46-61%), 40% methanol was then included in the aqueous sodium bicarbonate extraction solvent (pH 7.8) (Method II). Clean-up was on an Ochratest™ immunoaffinity column and OTA was determined by liquid chromatography (LC) with fluorescence detection. Recoveries of OTA from spiked cocoa powder (0.5 and 5 ng g(-1)) were 75-84%; while recoveries from chocolate were 93-94%. The optimized method was sensitive (limit of quantification (LOQ) = 0.07-0.08 ng g(-1)), accurate (recovery = 75-94%) and precise (coefficient of variation (CV) < 5%). It is applicable to cocoa and chocolate. Analysis of 32 samples of cocoa powder (16 alkalized and 16 natural) for OTA showed an incidence of 100%, with concentrations ranging from 0.25 to 7.8 ng g(-1); in six samples the OTA level exceeded 2 ng g(-1), the previously considered European Union limit for cocoa. The frequency of detection of OTA in 28 chocolate samples (21 dark or baking chocolate and seven milk chocolate) was also 100% with concentrations ranging from 0.05 to 1.4 ng g(-1); one sample had a level higher than the previously considered European Union limit for chocolate (1 ng g(-1)).
authors.affiliation: Food Research Division, Bureau of Chemical Safety, Food Directorate, Health Canada, 251 Sir Frederick Banting Driveway, Ottawa, ON, Canada.
authors.forename: A-M
authors.initials: AM
authors.lastname: Turcotte
authors.forename: P M
authors.initials: PM
authors.lastname: Scott
mesh_terms: D002099:Cacao / Q000737:chemistry*; D002182:Candy / Q000032:analysis*; D002846:Chromatography, Affinity; D002851:Chromatography, High Pressure Liquid; D005506:Food Contamination; D005511:Food Handling; D006863:Hydrogen-Ion Concentration; D057230:Limit of Detection; D009793:Ochratoxins / Q000032:analysis* / Q000302:isolation & purification; D015203:Reproducibility of Results; D012639:Seeds / Q000737:chemistry; D013050:Spectrometry, Fluorescence
chemical_list: D009793:Ochratoxins; C025589:ochratoxin A