Prevalence and Concentration level of Aflatoxin M1 in cow milk in Ethiopia: A Meta-analysis, Meta-regression, Exposure and Risk Assessment in Children

Milk is a complete nutritious food that composed of proteins, carbohydrates, vitamins, minerals, probiotics, and fats. Its’ nutritional roles are reduced because of contaminants. Among those contaminants Aflatoxin M1 (AFM1), hepatic bio-transformed aflatoxin B1, has been affecting public health due to its nature of genotoxicity and carcinogenicity. Aspergillus flavus and A. parasiticus are responsible for the production of AFB1. Some amounts of occurrence studies on AFM1 are available in Ethiopia, but there is paucity on meta-analysis and risk assessment works. Therefore, the current study was to determine pooled prevalence, estimates mean of concentration, exposure and risk assessment of AFM1 in raw cow milk in Ethiopia.Data were searched from databases including Google scholar, PubMed, and Science Direct according to Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guidelines and criterions for inclusions and exclusions were set before data collections commenced. Meta-analysis of data was conducted using random model effect by STATA version 17. Heterogeneity among studies was tested and further heterogeneity was assessed by sub-group analysis and meta-regression to explore heterogeneity through explaining moderators’ effect on the variation of effect sizes. Exposure and risk assessment were performed.Systematic review assessment ends with fourteen papers of seventeen studies that contain about 2,021 samples that were published from 2016 to 2024. Meta-analysis reveals 68.184% pooled prevalence of AFM1 which is 95% confident that the true values of pooled prevalence lies between 55.253% and 81.114%. In the current meta- analysis, heterogeneity metrics showed between study variance (Tau ² ) = 739.8792, percentage of heterogeneity (I ² ) = 100.00% and relative heterogeneity (H ² ) = 1.6e + 08. Publication bias test Egger test p-value = 0.4861 and Begg’s test p-value = 0.3031. There is a significant difference (P < 0.05) for prevalence of AFM1 within sub-group analysis except for Amhara region. In addition, sub-group analysis revealed highest prevalence of AFM1 in ELISA techniques, raw cow’s milk, and Oromia region. Meta-analysis estimated mean of concentration level of AFM1 is 0.316µg/L which is 95% confident that the true mean of concentration level lies between 0.163µg/L and 0.469µg/L. The current estimates of mean of concentration level of AFM1 is greater than 0.05µg/Kg of EU standard AFM1 permissible limit; however, it is lower than Ethiopian standard AFM1 permissible limit. AFM1 mean of concentration level data were heterogeneous (Tau ²  = 0.1008; I ² (%) = 100.00%; H ²  = 21,509.24) and there is no strong evidence for publication bias (p-value = 0.1082). Meta-regression indicates techniques of analysis significantly predict heterogeneity in prevalence of AFM1 by 36.58% of heterogeneity (p-value = 0.001). Moreover, meta-regression shows types of sample significantly explains heterogeneity in mean of concentration of AFM1 by 18.84% heterogeneity (p-value = 0.026). The estimated daily intake by children aged between 6 months to 2 years in Ethiopia is 5.62µg/Kg/day AFM1. Margin of exposure, hazard index, and cancer risk due to AFM1 is 101.42, 28.1, and 10.34, respectively. Paramount of pooled prevalence and estimates mean of concentration of AFM1 is highly contributing to public health concerns in Ethiopia. Therefore, this study warrants for consistent public awareness, regular mitigation plan and effective regulatory measures on AFM1.