Risk assessment of aflatoxin B₁ in 'egusi' melon seeds (Citrullus colocynthis)

‘Egusi’ (Citrullus colocynthis L.) is widely cultivated in Nigeria for its nutritious seeds, which is prone to deterioration in storage due to fungal infection hence, mycotoxin, especially aflatoxin B₁ contamination. Aflatoxin B₁ is the most potent natural carcinogen known and usually the major aflatoxin produced by toxigenic strains. This review aims to assess dietary exposure to aflatoxin B₁; estimate population risk for aflatoxin-induced hepatocellular carcinoma (HCC) and annual HCC burden for Nigeria due to consumption of contaminated melon seeds; with a view to recommending possible approaches to improve ‘egusi’ melon seeds safety. Secondary data obtained from literature on levels of aflatoxin B₁ contamination in ‘egusi’ melon seeds from farmers’ stores were used to determine dietary exposure to aflatoxin B₁ due to consumption of contaminated melon seeds. Population risk for aflatoxin-induced HCC and annual HCC burden were estimated based on the cancer potency of aflatoxin B₁ for hepatitis B virus (HBV) positive and negative individuals; and prevalence of HBV in Nigeria. Average aflatoxin B₁ dietary exposure values for adult and children sub-populations were 0.007 and 0.014 µg kg^-1, respectively. A total of 0.0006 or 0.0001% children and 0.0003 or 0.00006% adults in Nigeria have the potential of developing HCC, if they are hepatitis B surface antigen (HBsAg) positive or negative, respectively, due to the consumption of ‘egusi’ melon seeds contaminated with aflatoxin B₁. Determination of mycotoxin contamination along ‘egusi’ melon seed production chain (farm-to-table) and relationship between mould growth and mycotoxin production as a function of selected intrinsic and extrinsic factors are recommended in order to eliminate or reduce mycotoxin contamination, thereby mitigating associated risks.