Multiple mycotoxin exposure determined by urinary biomarkers in rural subsistence farmers in the former Transkei, South Africa

Abstract

Subsistence farmers are exposed to a range of mycotoxins. This study applied novel urinary multi-mycotoxin LC-MS/MS methods to determine multiple exposure biomarkers in the high oesophageal cancer region, Transkei, South Africa. Fifty-three female participants donated part of their maize-based evening meal and first void morning urine, which was analysed both with sample clean-up (single and multi-biomarker) and by a 'dilute-and-shoot' multi-biomarker method. Results were corrected for recovery with LOD for not detected. A single biomarker method detected fumonisin B1 (FB1) (87% incidence; mean±standard deviation 0.342±0.466 ng/mg creatinine) and deoxynivalenol (100%; mean 20.4±49.4 ng/mg creatinine) after hydrolysis with β-glucuronidase. The multi-biomarker 'dilute-and-shoot' method indicated deoxynivalenol-15-glucuronide was predominantly present. A multi-biomarker method with β-glucuronidase and immunoaffinity clean-up determined zearalenone (100%; 0.529±1.60 ng/mg creatinine), FB1 (96%; 1.52±2.17 ng/mg creatinine), α-zearalenol (92%; 0.614±1.91 ng/mg creatinine), deoxynivalenol (87%; 11.3±27.1 ng/mg creatinine), β-zearalenol (75%; 0.702±2.95 ng/mg creatinine) and ochratoxin A (98%; 0.041±0.086 ng/mg creatinine). These demonstrate the value of multi-biomarker methods in measuring exposures in populations exposed to multiple mycotoxins. This is the first finding of urinary deoxynivalenol, zearalenone, their conjugates, ochratoxin A and zearalenols in Transkei.

Keywords: AFB(1), AFM(1); B(2); Biomarker; DOM-1; DON; Deoxynivalenol; Exposure; FB(1), FB(2), fumonisin B(1); Fumonisin; IAC; JECFA; Joint FAO/WHO Expert Committee on Food Additives; LC–MS/MS; LOD; LOQ; Mycotoxin; NIV; OTA; PBS; PDI; PMTDI; UPLC; ZEA; ZEA-GlcA; Zearalenone; aflatoxin B(1), M(1); de-epoxydeoxynivalenol; deoxynivalenol, DON-GlcA, DON-glucuronide; immunoaffinity column; limit of detection; limit of quantification; liquid chromatography tandem mass spectrometry; nivalenol; ochratoxin A; phosphate buffered saline; probable daily intake; provisional maximum tolerable daily intake; ultra-performance liquid chromatograph(y); zearalenone; zearalenone-glucuronide; α-, β-ZOL; α-, β-zearalenol.