Comprehensive review of aflatoxin contamination, its occurrence, effects, management, and future perspectives
Yonas Syraji, P. R. Jeyaramraja, Tanje Mada, K. Gobikanila
Abstract
Mycotoxins are harmful substances produced by fungi, with aflatoxins - primarily produced by Aspergillus flavus and A. parasiticus – posing the greatest threat to food safety. First identified in 1960, aflatoxin B1 (AFB1), aflatoxin B2 (AFB2), aflatoxin G1 (AFG1), and aflatoxin G2 (AFG2) are of particular concern, with AFB1 recognized as the most potent hepatotoxin. These crystalline compounds fluoresce under ultraviolet light and are moderately soluble in organic solvents. Aflatoxins contaminate an estimated 25% of global crops, with contamination levels in several regions frequently exceeding international safety standards. Studies from Africa report widespread contamination in staple crops such as maize, groundnut, and sorghum, with both raw and processed products affected. In some cases, aflatoxin levels have reached as high as 2410 ppb – well above the EU’s maximum tolerable limit of 4 ppb. Recent findings in Ethiopia also show several groundnut varieties exceeding regulatory limits for AFB1. Climate change is expected to further aggravate contamination risks, particularly in Europe, where safe maize-growing regions are predicted to shift northward by 2050. Aflatoxins are associated with acute and chronic toxicity in humans and animals, leading to distinct and varied effects, including aflatoxicosis, hepato-carcinogenicity, retarded growth, suppressed immune system, and damage to the liver and kidneys. Aflatoxin production is influenced by both biotic (e.g., microbial interactions, host plant type) and abiotic (e.g., temperature, humidity, pH, water activity) factors. Given the severity of this issue, this review provides a comprehensive overview of aflatoxin occurrence, toxicological impacts, current mitigation strategies, and future approaches to strengthen prevention and control efforts globally.