Aflatoxin B1 Precise Test

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.

Aflatoxin B-1 (AFB(1)) is one of mycotoxins leading to serious food contaminations and human diseases. To solve these problems, biodegrading technique has been concerned. Previous researches showed that AFB(1) can be effectively degraded by the culture supernatant of many microorganisms. However, the biodegraded products have not been identified. In this study, to explore the structure of the products, the AFB(1) was degraded by the culture supernatant of Cladosporium uredinicola. Two biodegraded products of AFB(1) were collected by high performance liquid chromatography (HPLC) and analyzed by liquid chromatography quadruple time-of-flight mass spectrometry (LC-Q-TOF MS) and chromatography-tandem mass spectrometry (MS/MS). As a result, the molecular weight of the two products were 406 and 342, and the structure of the two products were inferred. The toxicity of the biodegraded products was evaluated based on quantitative structure-activity relationship (QSAR) and cytotoxicity experiment. In conclusion, the double bonds of AFB(1) had a high probability of being destroyed. The toxicity of the two biodegraded products compared with that of AFB(1) was reduced. The culture supernatant of C. uredinicola was used as an effective way to detoxify AFB(1).