Determination of Urinary Biomarkers for Assessment of Short-Term Human Exposure to Aflatoxins in São Paulo, Brazil

Abstract

In the present study, a longitudinal assessment was carried out to evaluate the short-term human exposure to aflatoxins in Pirassununga region, São Paulo, Brazil, by determination of urinary aflatoxins by a liquid chromatography coupled to mass sprectrometry (UPLC-MS/MS) method. Sixteen volunteers with ages ranging from 14 to 55 years old were instructed to collect the early morning first urine four times every three months, from June 2011 to March 2012, totaling 64 samples. Aflatoxin M1 (AFM1) was found in 39 samples (61%) at levels ranging from 0.19 to 12.7 pg·mg−1 creatinine (mean: 1.2 ± 2.0 pg·mg−1 creatinine). Residues of aflatoxins B1, B2, G1, G2 and aflatoxicol were not identified in any urine sample. No significant difference was found among the AFM1 mean levels in urine samples collected in the four sampling periods. The levels of AFM1 found in urine samples indicate a low short-term exposure of the population studied to aflatoxins through the diet, although further investigations are needed to assess other long-term biomarkers of exposure to AFB1.

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

“…No sample had AFB 1 or AFM 1 above the tolerance limits established by Brazilian regulations for peanut, corn or dairy products (Agência Nacional De Vigilância Sanitária, 2011). Peanuts products showed the highest values for AFB 1 contamination when compared with the other samples analyzed, which is in agreement with previous reports on the incidence of aflatoxins in those products (Jager et al, 2014;Magrine et al, 2011). Corn flour had the lowest AFB 1 mean concentration among corn products, but with the highest incidence of positive samples (>60%).…”

“…The mean concentrations of AFM 1 in urine samples collected in the 4 sampling times varied from 0.37 ± 0.23 to 1.70 ± 2.88 pg/mg creatinine, which are similar to the urinary AFM 1 levels (1.2 ± 2.0 pg/mg creatinine) reported in São Paulo by Jager et al (2014). The comparison between the results of the present study and those reported by other authors is difficult, because mostly of them expressed the urinary AFM 1 levels without correcting the value for the excreted creatinine.…”

“…Extraction and purification of AFM 1 in urine samples were performed by using immunoaffinity columns (Aflatest ® , Vicam, Watertown, MA, USA) according to Jager et al (2014). AFM 1 standard (Sigma, St Louis, MO, USA), prepared as previously described, was diluted to prepare calibration curves at levels of 0.25 to 5.0 pg/mL.…”

“…Assessment of aflatoxin intake by Brazilian population has been usually estimated in terms of probable daily intake (PDI) by analyzing the occurrence of AFB 1 in food products and the consumption data (Magrine et al, 2011;Jager et al, 2013). However, the human exposure to dietary aflatoxins by the biomarker approach have been assessed in only three studies conducted in the State of São Paulo, two describing the excretion of AFM 1 in human urine at levels ranging from 1.8 to 39.9 pg/mL (Romero et al, 2010) and from 0.19 to 12.7 pg/mg creatinine (Jager et al, 2014), and one reporting the AFB 1 -albumin adduct in blood samples in concentrations ranging from up to 57.3 pg/mg albumin (Scussel et al, 2006). There is no information available on the occurrence of urinary AFB 1 -N 7 -guanine associated to aflatoxin intake by the population in Brazil.…”

Association between Urinary Levels of Aflatoxin and Consumption of Food Linked to Maize or Cow Milk or Dairy Products

“…found no contaminated samples and had similar analytical accuracy with the limit of detection (LoD) ranging from 0.0013 to 0.0025 ng/mL [15,16]; Solfrizzo reports a limit of quantification (LoQ) of 0.02 ng/mL, and only 6% of samples over the LoQ [17]; in the Reggio Emilia study [14], 33% of the samples were over 0.02 ng/mL. Only surveys from industrialized countries with a tropical climate have found similar proportions of contaminated samples, although concentration values of aflatoxins were about ten times lower than those observed in our study [8,[18][19][20][21][22]; similar levels of contamination have been observed only in the surveys conducted in Africa and Asia [23][24][25][26][27][28][29]. Even though some results of the 2017 Reggio Emilia survey might suggest a small contribution from occupational exposure, it was clear that other sources of aflatoxins were present for the general population, with the most plausible exposure being food.…”