Aflatoxin Contamination of Ethiopian Hot Red Pepper and Risk Characterization: Dietary Exposure Assessment and Estimated Aflatoxin-Induced Hepatocellular Carcinoma

Aflatoxins are toxic fungal secondary metabolites, and their presence in the food chain can cause adverse health effects, impair trade and pose a significant economic burden. This study analyzed aflatoxin contamination along a hot pepper postharvest value chain, estimated its dietary exposure and its associated potential health risk to consumers. A total of 25 composite samples were analyzed for aflatoxins using immunoaffinity column cleanup and HPLC. Aflatoxins were detected in 48 % of the tested samples. Aflatoxin G1 was recorded at highest frequencies and contamination levels followed by AFB1. Uppermost contaminations (μg/kg) were recorded from packed pepper powder (43.61 AFG1 and 22.18 AFB1) followed by unpacked pepper powder (30.53 AFG1 and 13.50 AFB1). Five (42 %) of the positive samples exceeded the EU regulatory limits for AFB1 (> 5 μg/kg). Aflatoxin detection frequencies, aflatoxin types and contamination levels generally increased up along the chain. The mean daily intake dose was found as 1.04 ng AFB1/kg bw/day and the cancer risk was estimated to be 0.0188, 0.0098 and 0.0286 cancer cases/year/100,000 population of hepatitis B surface antigen positive, negative and adult subpopulation, respectively. This cancer risk level can be considered “essentially negligible” as compared to 1 x 10-5 cancer risk level established by some agencies. However, as this study was dependent on a single food commodity, and aflatoxin contamination level varies from year to year and location to locations, the risk level of this study should not be taken as assurance for safe risk level. In addition, if aggregate dietary exposure is considered, possible health risk would be high. In conclusion, the increased trends of detection frequencies, aflatoxin types and contamination levels up along the value chain signified the possible occurrence of the toxin and their associated health risk as the food commodity approaches consumption. Because complete elimination of aflatoxin is almost unachievable once contamination has happened, preventative management efforts should target the value chain.

黄曲霉毒素（Aflatoxins）是具有毒性的真菌次生代谢物，其在食物链中的存在可引发不良健康效应、阻碍贸易，并造成显著的经济负担。
本研究针对辣椒采后价值链中的黄曲霉毒素污染情况展开分析，估算了消费者的膳食暴露量及其潜在关联健康风险。
共采集25份复合样品，采用免疫亲和柱净化结合高效液相色谱（HPLC）法对黄曲霉毒素进行检测。结果显示，48%的受检样品中检出黄曲霉毒素，其中黄曲霉毒素G1（AFG1）的检出频率与污染水平最高，其次为黄曲霉毒素B1（AFB1）。
污染水平最高的样品为预包装辣椒粉（黄曲霉毒素G1含量43.61 μg/kg、黄曲霉毒素B1含量22.18 μg/kg），其次为散装辣椒粉（黄曲霉毒素G1含量30.53 μg/kg、黄曲霉毒素B1含量13.50 μg/kg）。
5份阳性样品（占比42%）超出了欧盟针对黄曲霉毒素B1的监管限值（＞5 μg/kg）。
整体而言，沿价值链方向，黄曲霉毒素的检出频率、毒素类型与污染水平均呈上升趋势。
研究测得平均每日摄入剂量为1.04纳克黄曲霉毒素B1/千克体重/天，针对乙型肝炎表面抗原阳性、阴性人群以及成人亚人群，其癌症风险分别估算为0.0188、0.0098与0.0286例/年/10万人。
相较于部分机构设定的1×10^-5癌症风险基准，本次研究的癌症风险水平可被视为“基本可忽略”。
但需注意，本研究仅针对单一食品品类展开，且黄曲霉毒素污染水平会随年份与地域发生变化，因此本研究的风险评估结果不应被视作安全风险的保障依据。此外，若考虑总膳食暴露情况，潜在健康风险可能更高。
综上，沿价值链上升的黄曲霉毒素检出频率、毒素类型与污染水平趋势表明，随着食品临近消费环节，该毒素的污染及其关联健康风险可能随之升高。鉴于污染发生后几乎无法完全清除黄曲霉毒素，因此预防性管理工作应聚焦于整条采后价值链。