Dried fruits marketed in Russia: multi-mycotoxin contamination

Abstract

Mycotoxins (MT) - secondary metabolites of micromycetes - are natural contaminants of plant products. Fruits are particularly susceptible to fungal contamination and MT accumulation due to high sugar content. It can occur at any production stage: during vegetation, drying and storage. The most hazardous MT - aflatoxins (AFLs) and ochratoxin A (OTA) - are regulated in dried fruits in some countries. However, their maximum levels (ML) were not set in Russia yet. The present research was aimed at the evaluation of MT contamination of dried fruits marketed in Russia. Material and methods. 54 samples of dried dates (n=11), apricots (n=9), raisins (n=9), prunes (n=7), figs (n=6), apples (n=3) and mixtures for compote (n=9) were analyzed for 32 MTs by HPLC-MS/MS with positive/negative ESI in the MRM mode. Results. OTA and fumonisins (FBs) were the major regulated contaminants, their occurrence proved to be 10 and 17% correspondingly. Emergent metabolites of Fusarium spp. enniatin A (ENN A, 22%) and beauvericin (BEA, 15%); Penicillium spp. mycophenolic and cyclopiazonic acids (MPA and CPA, about 19%); Alternaria spp. tentoxin (TE, 17%) were detected also. Two-thirds of positive samples were contaminated with two and more MTs. All studied samples could be referred as safe within the EU regulations. Conclusion. Some kinds of dry fruits proved to be susceptible to contamination with particular MTs. Characteristic pattern for raisin was the OTA and MPA combination, for figs - FBs and CPA. According to literature data concerning occurrence and safety of MTs and the results of our survey, the long-term monitoring of AFLs and OTA in dry fruits and AFLs, OTA, FBs and CPA in figs from different regions of Russia is necessary to assess the need for setting of MLs of these MTs.