Resumen de Exposure assessment of mycotoxins in food and biological samples through high resolution mass spectrometry-based strategies
Mycotoxins are toxic secondary metabolites produced by several fungi genera that are frequently found in food products. If ingested, mycotoxins can display a broad range of adverse effect. In order to reduce the health impact due to the dietary intake of mycotoxins, the Commission Regulation No 1881/2006, released by the European Commission, sets maximum limits (MLs) for certain mycotoxins in several food products. As a complementary tool, the Panel on Contaminants in the Food Chain (CONTAM Panel) have proposed tolerable daily intake values (TDIs) that establish the maximum quantity of a certain mycotoxin that can be daily ingested over a lifetime without an appreciable health risk. Traditionally, the exposure to mycotoxins have been estimated through the combination of consumption surveys and contamination data after analyzing food matrices, but current approaches are evolving towards more accurate and individualized strategies. Human biomonitoring represents an alternative tool that can provide reliable results through the direct measurement of mycotoxins and/or their metabolites in biological samples. Therefore, the present doctoral thesis focused on the development of analytical methodologies based on liquid chromatography coupled to either quadrupole-time of flight or quadrupole-Orbitrap high resolution mass spectrometry for the simultaneous determination of multiple mycotoxins in food and biological matrices for later exposure assessment.
Out of the 85 food samples analyzed, 60 tested positive for at least one mycotoxin (70%) but at low concentration levels (< 50 ppb). Co-occurrence of mycotoxins was detected in 42 food samples, meaning the 70% of the total positive samples. The most common co-occurrence events included zearalenone alongside its derived forms and combinations of enniatins. Exposure assessment based on consumption and contamination data highlighted that daily intake of alternariol, alternariol monomethyl ether and zearalenone and its derived forms might not represent a health concern by themselves, but their contribution to the total exposure should be taken into consideration specially with susceptible cohorts like children.
Human biomonitoring consisted in the analysis of two different matrices: urine and hair as a novel matrix. Analysis of human urine revealed the presence of either citrinin or its metabolite dihydrocitrinone in 142 out of 300 samples (47%), whereas T-2 and HT-2 were detected in 63 (21%) and 90 (30%) samples, respectively. Exposure assessment based on the measurement of urinary citrinin biomarker revealed an exposure accounting for 8% to 40% of the tolerable daily intake, being children (< 18 years old) the most exposed population group. Although no correlation between the measured levels and the dietary intake can be established for T-2 yet, a high prevalence of the T-2 hydroxylated metabolites, especially 3-hydroxy-T-2 toxin, occurring in 299 out of 300 samples (99.7%) was observed.
Regarding hair samples, frequent contamination was observed with 43 out of 100 samples testing positive for at least one mycotoxin, being enniatins and aflatoxin B1 the most prevalent compounds. Concentration values ranged from 2.7 to 106 ng/g and corresponded to a cumulative exposure over five months according to the length of the samples. Retrospective non-targeted screening in hair samples revealed the presence of 128 mycotoxins, including some relevant compounds such as patulin (85%). Therefore, the here-developed and validated methodology resulted to be useful for a broad range of mycotoxins and revealed hair as a potential biological matrix for monitoring their accumulation.
