Detection of aflatoxin in raw and pasteurized milk by high-performance liquid chromatography (HPLC) in central Ethiopia

Aflatoxins are a group of structurally related mycotoxins produced by the Aspergillus flavus, Aspergillus parasiticus, and Aspergillus nomius species as secondary metabolites. Well-known forms of Aflatoxin are AFB1, AFB2, AFG1, AFG2, AFM1, and AFM2. aflatoxin B1 is the most prevalent one. It can be metabolized in the liver and excreted as aflatoxin M1 in milk. Both forms have mutagenic and carcinogenic effects. In Ethiopia, there is limited information on the occurrence and contamination level of aflatoxin in raw and pasteurized milk. The present study was conducted in the Addis Ababa milk shed area to detect and quantify the level of Aflatoxin M1 in raw and pasteurized milk. A cross-sectional study was conducted from October 2020 to May 2021 on a total of 114 cow milk samples consisting of 60 raw milk and 54 pasteurized milk samples with the aim of detecting and quantifying the amount of aflatoxin M1 in raw and pasteurized milk in central Ethiopia by high-performance liquid chromatography (HPLC) using C18 column with fluorescence detector. AFM1 was detected in 79 (69.3%) of the 114 tested milk samples. The maximum and mean concentrations were 0.893 µg/L and 0.0465 µg/L, respectively. 25.4% of them contain AFM1 above the maximum limit of EU (0.05 µg/L), and 1.8% contained above the maximum limit of CES278 and FDA (0.5 µg/L). 26.7% of the samples from Sebata and 6.7% from Sululta contain above the maximum limit of EU (0.05 µg/L). Higher contamination of AFM1 was detected in pasteurized milk (96.3%) than in raw milk (16.7%). 35.2% of pasteurized and 16% of raw milk contained AFM1 above the maximum limit of EU0.05 µg /L. The study results showed a significant difference in AFM1 occurrence with feed type, storage time, and milk type. The current AFM1 concentration level in raw and pasteurized milk was not safe for human consumption in the study areas. Due to its heat resistance, AFM1 is found in pasteurized milk and has great health effects. Creating awareness of feed management for feed producers and farmers and developing risk mitigation methods are crucial in order to reduce public health threats.