Assessment of aflatoxin exposure using serum and urinary biomarkers in Sao Paulo, Brazil: A pilot study

The aim of this study was to evaluate the human exposure of individuals from Pirassununga, Brazil, to dietary aflatoxins B-1 (AFB(1)) and M-1 (AFM(1)) by determination of serum AFB(1)-lysine and urinary aflatoxin biomarkers (AFM(1) and AFB(1)-N-7-guanine). The participants were recruited among employees from a Campus of the University of Sao Paulo, which provided food samples from their homes, as well as serum and urine samples four times every three months, from June 2011 until March 2012. The probable daily intake (PDI) of aflatoxin was estimated by using the results from analysis of food products collected by the time of samples collection, and data from a 24-hour dietary recall questionnaire. Analyses of AFB(1) and AFM(1) in food samples were conducted by high-performance liquid chromatography with fluorescence detection. Biomarkers in serum and urine were determined by tandem mass spectrometry. AFB(1) and AFM(1) were detected in 38 samples of cereals (28%, N = 136) and 31 milk products (36%, N = 86), respectively. AFB(1)-lysine and AFB(1)-N-7-guanine and were not detected in serum or urine samples, respectively. However, AFM(1) was found in 74 urine samples (65%), at mean levels in the 4 sampling times ranging from 0.37 +/- 0.23 to 1.70 +/- 2.88 pg/mg creatinine. The mean PDI varied among different sampling times, ranging from 0.09 +/- 0.09 to 1.35 +/- 5.98 ng/kg body weight/day. A modest though significant correlation (r = 0.45; p = 0.03; N = 23) was found for the first time in Brazil between the AFM(1) concentration in urine and the PDI for total aflatoxins (AFB(1) + AFM(1)) in sampling 1 (June 2011). Urinary AEA was confirmed as very sensitive for monitoring the human exposure to dietary aflatoxin. Further studies using serum and urinary biomarkers are needed to estimate the aflatoxin exposure of populations in higher risk areas in Brazil. (C) 2015 Elsevier GmbH. All rights reserved.