Study of co-occurrence of mycotoxins in cocoa beans in Brazil by liquid chromatography-tandem mass spectrometry (LC-MS/MS).

In this study, 135 samples of cocoa beans collected in the Amazon and Atlantic Forest regions of Brazil were analysed to evaluate the possible co-occurrence of 34 mycotoxins. The results indicate that 42% of the cocoa samples exhibited quantifiable levels for 11 mycotoxins: aflatoxins (AFs) B1, B2 and G1; ochratoxin A; citrinin; cyclopiazonic acid; tenuazonic acid; paxilline; sterigmatocystin; zearalenone and fumonisin B2. Of the samples, 18% exhibited the co-occurrence of up to six mycotoxins. No toxins belonging to the groups of trichothecenes or ergot alkaloids were detected. Contingency analysis of the incidence of mycotoxins did not show significant differences between the two regions evaluated. Seven samples were contaminated with AFs, while only one contained ochratoxin A above 10 µg kg-1. The accuracy of the method was evaluated by proficiency testing for ochratoxin A, where satisfactory Z-scores were obtained.

Validation and estimation of uncertainty of an LC-MS/MS method for the simultaneous determination of 34 mycotoxins in cocoa beans.

The aim of this manuscript was to validate and apply an analytical methodology for the simultaneous determination of 34 mycotoxins in cocoa. The extraction method used in the tests was a liquid-liquid partition by NaCl addition with a freezing step followed by quantification using LC-MS/MS. The results were discussed based on national and international directives for food contaminants. The recoveries and precision were adequate, except for the mycotoxins ionized with the ammonium adduct (NH4+), E-cristinine and ß-ZOL. This result directly influenced the measurement uncertainty of these mycotoxins, because the precision and the correction factor of the recovery were the factors with the greatest impact on the uncertainty of the method. The evaluation of the matrix effect showed considerable signal suppression for 53 % of the evaluated mycotoxins. Nevertheless, the mycotoxins exhibited relatively low quantification limits, with values between 1 and 75 µg kg-1. The validated methodology was applied to 15 cocoa samples collected in warehouses in Brazil. Positive results were found for all the evaluated samples, in which nine toxins were detected out of the 34 investigated.