This study also showed that processed milk samples had low contamination levels (8.6%) contributed mainly
by fermented milk (50.0%) and yoghurt (37.5%). Both fresh processed milk and UHT had no contamination.
Generally, processed milk did not show any evidence of contamination, median 0.00 with a minimum of 0.00
μg/l and a maximum of 0.69 μg/l Table 5 & Table 6. This could be attributed to the treatment effects of raw
milk which could have lowered the concentration of aflatoxin M1 in the processed samples. According to studies
on the effect of various heat treatments on AFM1 content of cow’s milk, it was reported that sterilization of
milk at 121˚C for 15 min caused 12.21% degradation of AFM1, whereas boiling decreased AFM1 by 14.50%
[27]. It was concluded that destruction of AFM1 depends on time and temperature combination of the heat
treatment applied. In another study by [28], it was observed that pasteurization caused a decrease in the level of
AFM1 at the rate of 7.62%. Other studies [29] showed that pasteurization can partially reduce the amount of
AFM1 in milk. However, some reports show that aflatoxins are stable during heat-treatments such as pasteurization
and sterilization [30]. The effect of fermentation was assessed by [31]. It was reported that AFM1 levels in
all yoghurt samples showed a significant decrease from those initially present in milk. This could be attributed
to factors such as low pH, formation of organic acids or other fermentation by-products, and even to the presence
of lactic acid bacteria [4].