Without governmental policies and thresholds to regulate AFL levels in food supplies, the human population in South America is continuously exposed to these mycotoxins. Although some data suggest that exposure to food contaminated with AFLs can lead to hepatocellular carcinoma (HCC), published data on acute and chronic human aflatoxicosis outbreaks in South American communities are lacking. Although the data are scarce or nonexistent, AFL exposure remains an important issue with regard to food safety and public health. Safety assessments must be undertaken by South American countries, as data suggest that long-term exposure might lead to HCC development or other diseases.79 An Argentina study performed by Lopes et al.39 showed 0.47 ng/mL AFB1 in one of 13 blood samples from donors with hepatic diseases.
Evaluation of AFL exposure by measuring toxin levels in contaminated foods can be difficult to interpret due to the heterogeneous distribution of AFLs. Additionally, the dietary intake of a given food can be highly variable and unreliably reported. Genetic variability in AFB1 metabolism may also influence the level of exposure at the individual level; therefore, an alternative for evaluating AFL exposure is to estimate levels using specific biological markers (biomarkers) based on an understanding of the metabolism of the compound. For AFB1, these include aflatoxin-N7-guanine (AFB1-N7-gua) in the urine, or aflatoxin-albumin (AFB1-alb) in the blood. Using the AFB1-alb biomarker assay approach, a study was carried out by Haas et al.34 to assess the level of exposure to AFB1 in a Brazilian population. A blood sample was taken from urban residents (n = 50; ages 18 to 52) in 1999 at the Blood Center of Antonio Carlos de Camargo Hospital, Sao Paulo. Serum albumin was extracted and digested and AFB1-alb adduct levels were determined by enzyme-linked immunosorbent assay (ELISA). AFB1-alb adducts were detected in 31/50 (62%) samples (range, 0 to 57.3 pg AFB1-lys adducts per mg of blood albumin [pg/mg]). The mean level for those individuals who tested positive was 14.9 pg/mg. Males had the two highest levels, measured at 57.1 and 57.3 pg/mg. The levels in this study were similar to those observed in the Philippines.78 This was the first study from South America that determined human AFB1 exposure using the biomarker approach. These data warrant further investigation of both the sources and consequences of exposure to this potent toxin in Brazil and other South American countries.
The purpose of this review is to summarize recent literature published since 1993 that addresses the natural occurrence of AFLs in South America. This information serves as an indicator of the current research effort and the various areas of interest in the countries across the continent. Due to the small quantity of South American data published in English-language journals, data reported in Spanish- or Portuguese-language journals, good-quality data published in Latin American Myc-otoxicology conference proceedings, and official data obtained from South American private and governmental accredited laboratories of mycotoxin analysis are presented here. In order to maintain regional perspectives, the review has been subdivided into the geographical areas of Northern (Ecuador, Colombia, French Guyana, Guyana, Suriname, Venezuela), Southern (Argentina, Chile, Uruguay), Eastern (Brazil, a major region by itself), and Western (Bolivia, Peru, Paraguay) South America. Most of the AFL data are from the Eastern region.
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