Prevalence of Aflatoxin B1 and Other Quality Indicators in Artisanal Peanut Oil from Small-Scale Workshops in Nanning, China

Objective: To characterize aflatoxin B1 (AFB1) contamination, oil-quality variation, workshop hygiene, and modeled dietary risk associated with artisanal peanut oil produced by small-scale workshops in Nanning, China. Methods: A cross-sectional study was conducted in 144 workshops across all 12 county-level administrative areas of Nanning, with one peanut-oil sample collected from each workshop. On-site hygiene practices were assessed using a structured 13-item instrument. AFB1 concentration, acid value, and peroxide value were measured using national standard methods. Regional differences were evaluated using non-parametric tests, and K-means clustering was applied to characterize multivariate quality profiles. Dietary exposure was assessed using estimated daily intake (EDI), margin of exposure (MOE), and modeled AFB1-attributable hepatocellular carcinoma (HCC) risk. Results: AFB1 was detected in 88.2% of samples, while 3.5% exceeded the Chinese maximum level of 20 μg/kg. Samples from counties had significantly higher AFB1 concentrations, acid values, and peroxide values than those from municipal districts (all p < 0.001). Compliance was relatively high for basic hygiene and spatial separation, whereas routine contaminant testing was reported by only 18% of workshops and aflatoxin-degradation equipment was available in 35%. The primary clustering analysis identified overall-low (81.2%), AFB1-dominant (9.7%), and rancidity-dominant (9.0%) profiles, whereas sensitivity analysis after log10 transformation favored a broader two-cluster structure. Estimated AFB1 intake was higher under the rural than the urban scenario (2.6436 vs. 0.6890 ng/kg bw/day), with corresponding MOE values of 151.31 and 580.55. Modeled HCC risk was also higher under the rural scenario and under the hepatitis B surface antigen-positive scenario. Conclusion: Artisanal peanut oil from small-scale workshops in Nanning showed frequent AFB1 detection, marked regional variation in multiple quality indicators, and limited implementation of contaminant-specific control practices. These findings support closer attention to routine AFB1 monitoring, storage management, and broader quality control, particularly in county settings.