HPLC-MS/MS Method for the Detection of Selected Toxic Metabolites Produced byPenicilliumspp. in Nuts

Penicilliumspp. are emerging as producers of mycotoxins and other toxic metabolites in nuts. A HPLC-MS/MS method was developed to detect 19 metabolites produced byPenicilliumspp. on chestnuts, hazelnuts, walnuts and almonds. Two extraction methods were developed, one for chestnuts and one for the other three nuts. The recovery, LOD, LOQ and matrix effect were determined for each analyte and matrix. Correlation coefficients were always >99.99%. In walnuts, a strong signal suppression was observed for most analytes and patulin could not be detected. Six strains:Penicillium bialowiezense,P. brevicompactum,P. crustosum,P. expansum,P. glabrumandP. solitum, isolated from chestnuts, were inoculated on four nuts. Chestnuts favored the production of the largest number ofPenicilliumtoxic metabolites. The method was used for the analysis of 41 commercial samples: 71% showed to be contaminated byPenicillium-toxins. Cyclopenin and cyclopenol were the most frequently detected metabolites, with an incidence of 32% and 68%, respectively. Due to the risk of contamination of nuts withPenicillium-toxins, future studies and legislation should consider a larger number of mycotoxins.