Biomonitoring of Mycotoxins in Urine: Pilot Study in Mill Workers

Abstract

Contamination of grains with mycotoxins results in a dietary background exposure of the general population. In occupational settings such as during processing of raw materials as in milling, an additional mycotoxin exposure by inhalation is possible. Biomonitoring is an integrative approach to assess human exposure from various sources and by all routes. To investigate possible workplace exposure to mycotoxins, a pilot study was conducted that compared levels of urinary biomarkers in mill workers to those in a control group with dietary mycotoxin intake alone. Workers (n = 17) from three grain mills in North Rhine Westphalia, Germany, provided spot urines during shift; volunteers (n = 13, IfADo staff) with matched age structure served as control group. The mycotoxins selected for biomarker analysis were citrinin (CIT) deoxynivalenol (DON), ochratoxin A (OTA), and zearalenone (ZEN). Immunoaffinity columns (CIT, DON, ZEN) or liquid-liquid extraction (OTA) was employed for urine sample cleanup prior to targeted analysis by liquid chromatography with tandem mass spectrometry (LC-MS/MS) or by high-performance liquid chromatography (HPLC). In addition, mycotoxin metabolites that may be formed in the organism were analyzed, including deepoxy-deoxynivalenol (DOM-1), ochratoxin alpha (OTα), dihydrocitrinone (DH-CIT), and α- and β-zearalenol (α- and β-ZEL), as well as phase II metabolites that were hydrolyzed with β-glucuronidase/arylsulfatase prior to sample cleanup. All analyte concentrations were adjusted for creatinine (crea) content in the spot urine samples. Citrinin, DON, OTA, and ZEN were detected in nearly all urine samples from mill workers and controls. Interestingly, DH-CIT was found at higher mean levels than the parent compound (~0.14 and 0.045 µg/g crea, respectively), suggesting an effective metabolism of CIT in humans. Other metabolites DOM-1, OTα, and α- and β-ZEL were detected less frequently in urine. Deoxynivalenol was detected at the highest concentrations (mean ~6 µg/g crea), followed by OTA (mean ~0.08 µg/g crea); ZEN (mean ~0.03 µg/g crea) and its metabolites appeared in urine at lower levels. Mycotoxin biomarker levels in urine from mill workers and controls were not significantly different. From these results it is concluded that biomarker levels measured in urine samples from the two cohorts reflect mainly dietary mycotoxin exposure. An additional occupational (inhalational) exposure of mill workers, if any, is apparently low at the investigated workplaces.

Mycotoxin Biomarkers of Exposure: A Comprehensive Review

“…Noteworthy, DH‐CIT is less toxic than CIT (Föllmann, Behm, & Degen, ), so the formation of DH‐CIT is considered as a detoxification reaction. The higher presence of DH‐CIT than free CIT in human urine was similar in recently reported studies (Ali, Blaszkewicz, Alim, Hossain, & Degen, ; Degen et al., ; Föllmann, Ali, Blaszkewicz, & Degen, ; Heyndrickx et al., ). Consequently, as DH‐CIT has a large presence as CIT metabolite in urine, it is essential to consider this metabolite in the evaluation of CIT exposure.…”

Dietary Deoxynivalenol Exposure Assessment in University Students from Japan

“…Urinary DON biomarkers have been shown to be a good indicator for DON exposure as they show a good correlation with food consumption especially with cereal, maize and wheat products [8][9][10][11][12][13][14][15] . According to the dietary recall survey, the major source for DON exposure for the Japanese university students tested here was likely to be wheat products.…”

“…Enzyme hydrolysis during the extraction step has been proposed in order to increase the accuracy in determining DON levels in urine, which converts the conjugated DON back to its free form so that total urinary DON is measured to assess the exposure 7) . Total DON (extraction with enzyme digestion), free DON, DON-3-GlcA and DON-15-GlcA are all suitable biomarkers for DON exposure assessment, while DOM-1 showed a very low concentration in human urine samples [8][9][10][11][12][13][14][15] . The benefit of utilizing biomarker measurement, compared to the traditional dietary exposure assessment, to assess the DON exposure is that this method can cover DON exposure through different exposure routes.…”

Occupational Exposure to Mycotoxins: Current Knowledge and Prospects

“…In Portugal, AFB 1 was detected in the serum of 50% of poultry workers, whereas it was absent from all the serum from controls (Viegas et al, 2016). On the other hand, a study in Germany using biomonitoring to assess exposure to certain mycotoxins in mill workers failed to reveal such exposure in urine spot samples (Föllmann et al, 2016). Indeed, no significant difference in biomarker levels was observed between mill workers and control group.…”

“…Similarly to the studies reported in Table 1, until 2015, studies focused on one mycotoxin alone (aflatoxins and ochratoxins were the most studied); but some studies were subsequently able to report on several mycotoxins in the same biological sample, as analytical resources expanded. These articles (Föllmann et al, 2016;Ferri et al, 2017;Viegas et al, 2017) again demonstrated that the most common exposure scenario is co-exposure to several mycotoxins. However-and this is one of the limitations of using biomonitoringit is impossible to conclude whether exposure results solely from the working environment or whether food intake is a also a contributing factor.…”