Aflatoxins: The Silent Food Contaminant Behind Hundreds of Thousands of Deaths

Aflatoxins, the toxic compounds produced by Aspergillus flavus and Aspergillus parasiticus fungi, remain one of the world’s most pervasive yet underappreciated food safety threats. A new narrative review published in the journal Genes and Environment on 31 July 2026 pulls together decades of evidence on how much of the global population is exposed, through which routes the toxins enter the body, what they do to human health, and which detection technologies can identify them. The review, guided by the Scale for the Assessment of Narrative Review Articles framework, synthesized literature retrieved from PubMed, Scopus, Web of Science, and Google Scholar covering studies published between January 2000 and January 2026.

The scale of exposure is staggering. According to estimates cited in the review, nearly 4.5 billion people worldwide consume food products contaminated with aflatoxin residues, and more than 5 billion people in low-income regions experience continuous exposure because they rely on vulnerable staple crops. The Food and Agriculture Organization has estimated that about 25 percent of global agricultural commodities are contaminated with mycotoxins during pre-harvest, post-harvest, or storage. Aflatoxins resist processing and cooking, remaining stable despite conventional decontamination methods, which means contamination that enters the food chain is difficult to remove before consumption.

The review’s regional contamination data illustrate how severe the problem can be. In Côte d’Ivoire, every peanut paste sample tested was contaminated with aflatoxin B1, with the highest concentrations reaching 4535 micrograms per kilogram for AFB1 and 8094 micrograms per kilogram for total aflatoxins, and 99 percent of samples exceeded European Union limits of 2 micrograms per kilogram for AFB1 and 4 micrograms per kilogram for total aflatoxins. In the same country, maize samples showed 96 percent AFB1 contamination with 58 percent exceeding EU limits, while rice showed 57 percent contamination with 24 percent exceeding limits. In Malawi, about 20 percent of maize samples exceeded national aflatoxin limits, with a maximum level of 140 micrograms per kilogram. These figures indicate that peanut paste and maize carry considerably greater aflatoxin risk than rice in the surveyed settings.

Human biomonitoring confirms that contamination in food translates into measurable internal exposure. In Malaysia, AFB1–lysine adducts were detected in 97 percent of serum samples. In Nepal, biomarkers were detected in 94 percent of pregnant women, at levels ranging from 0.45 to 2939.30 picograms per milligram. In Bangladesh, biomarkers were found in all mothers, cord blood samples, and infants tested, confirming that exposure begins in utero and continues into infancy. In East Africa, AF-alb adducts were detected in 78 percent of serum samples in Kenya, 98 percent of participants in Uganda showed detectable levels, and detection rates among young children in Tanzania ranged from 67 to 99 percent. In Egypt, one study detected AF-alb in 67 percent of samples while another reported 35.6 percent in pregnant women.

Dietary ingestion is the main route of exposure, with estimated daily intakes ranging from 0.3 to 180 nanograms per kilogram of body weight depending on region and diet. The Joint FAO/WHO Expert Committee on Food Additives estimated mean daily intake levels of 0.93 to 2.45 nanograms per kilogram in Europe, 3.5 to 180 nanograms per kilogram in Africa, and 0.3 to 53 nanograms per kilogram in Asia. But food is not the only pathway. Aflatoxins cross the placental barrier, exposing fetuses before birth. The metabolite aflatoxin M1 appears in breast milk within 12 to 24 hours after maternal intake of contaminated foods, with measured concentrations of 0.01 to 0.55 nanograms per milliliter in Tanzanian nursing mothers. Complementary weaning foods such as maize and groundnuts add further exposure in early childhood, and occupational inhalation of contaminated dust in food processing, grain storage, and feed industries contributes additional burden.

The health consequences are serious and span the life course. The review reports that aflatoxin exposure is responsible for 4.6 to 28.2 percent of global hepatocellular carcinoma cases and contributes to approximately 250,000 deaths annually, with children facing an associated 2 to 4-fold higher risk of cancer. AFB1 is classified as a Group 1 human carcinogen by the International Agency for Research on Cancer. A systematic review and meta-analysis of 17 case-control and cohort studies from sub-Saharan Africa, China, and Taiwan estimated that aflatoxin exposure contributed to 17 percent of hepatocellular carcinoma cases, with a higher population attributable risk among HBV-positive individuals at 21 percent than among HBV-negative populations at 8.8 percent, underscoring a strong synergistic interaction between aflatoxin exposure and hepatitis B infection. In Ethiopia, persistent exposure has been associated with an estimated 11 to 288 hepatocellular carcinoma cases, rising to 21 to 643 cases when co-exposure with hepatitis B is considered.

Beyond cancer, the evidence links aflatoxin exposure to impaired child growth and immune suppression. In a cross-sectional study of 480 children aged 9 months to 5 years in Benin and Togo, aflatoxin biomarkers increased after the introduction of complementary foods, peaked around three years of age, and showed significant inverse associations with height-for-age, weight-for-age, and weight-for-height scores after adjustment for confounding variables. In The Gambia, children aged 6 to 9 years with detectable aflatoxin–albumin adducts had significantly lower concentrations of secretory immunoglobulin A than unexposed children. In a cohort of 64 adults in Ghana, higher aflatoxin–albumin adduct concentrations were associated with significantly reduced proportions of activated T lymphocytes and activated B cells, and among HIV-positive Ghanaians, higher exposure was linked to lower frequencies of regulatory and naive CD4+ T cells and B lymphocytes, as well as increased odds of elevated direct bilirubin and higher HIV viral load.

There is also evidence that exposure reduction works. In China, public health interventions introduced during the 1980s, including a dietary transition from maize-based to rice-based diets with lower aflatoxin contamination and nationwide hepatitis B vaccination, were associated with an approximately 65 percent reduction in primary liver cancer mortality linked to these changes, based on Qidong Cancer Registry data combined with serum AF-alb measurements from seven cohorts between 1982 and 2012. AF-alb concentrations in those cohorts declined from 19.3 picograms per milligram in 1989 to undetectable levels by 2012, providing direct biological evidence of successful exposure mitigation at the community level.

Detection technology has advanced considerably since aflatoxins were first recognized in the United Kingdom in 1960 following the turkey X disease outbreak that killed over 100,000 turkeys and other poultry. High-performance liquid chromatography coupled with fluorescence detection is widely used for routine monitoring, while liquid chromatography–tandem mass spectrometry is regarded as the gold standard, detecting aflatoxins below 1 nanogram per milliliter and enabling simultaneous identification of AFB1, AFM1, AFQ1, and AFP1. Electrochemical immunosensors represent the most sensitive biosensor class, with one multi-walled carbon nanotube-modified platform achieving a limit of detection of 0.3 picograms per milliliter. Lateral flow assays provide rapid, low-cost, instrument-free field screening but with lower sensitivity. Emerging approaches include aptamer-based biosensors, surface-enhanced Raman scattering platforms, paper-based microfluidic devices, and smartphone-assisted quantification, arranged in a tiered ecosystem in which confirmatory laboratory methods, mid-level biosensors, and rapid field tests play complementary roles.

The review’s authors acknowledge important limitations. Because the work is a narrative synthesis rather than a systematic review, study selection was based on relevance and availability rather than predefined eligibility criteria, which may introduce selection bias. The evidence base is dominated by cross-sectional and heterogeneous studies, which limits causal inference, and heterogeneity in biomarkers, methods, and exposure windows constrains comparability and global burden estimation. Several emerging detection technologies remain experimental prototypes not yet validated under real-world field conditions, and the review did not include quantitative cost or scalability comparisons. The authors conclude that aflatoxin exposure is a major global public health concern and that improved detection methods and food safety measures are essential to reduce exposure and disease burden, with future priorities including harmonized biomonitoring, integration of field screening with confirmatory methods, and longitudinal studies to improve risk quantification.

Subject of Research: Global aflatoxin exposure, health effects, and detection technologies

Article Title: Aflatoxin exposure and health impacts: global burden and advances in detection technologies

Article References: Bereda, G. (2026). Aflatoxin exposure and health impacts: global burden and advances in detection technologies. Genes and Environment, 48(1), Article 14. https://doi.org/10.1186/s41021-026-00363-1

Image Credits: AI Generated

DOI: 10.1186/s41021-026-00363-1

Keywords: aflatoxins, food safety, mycotoxins, hepatocellular carcinoma, hepatitis B, biomonitoring, LC-MS/MS, biosensors, child growth, Aspergillus, public health, detection technology