Raw milk samples showed evidence of Aflatoxin M1 contamination, median 0.09 with a minimum of 0.00
μg/l and a maximum of 2.93 μg/l. The higher prevalence rate (100%) along with moderately higher contamination
level of AFM1 in the raw milk samples indicate that lactating cows in Bomet are exposed to AFB1-contaminated
feeds in different study sites. However, it was not possible to determine the level of AFB1 in the feed of
dairy cattle in the present study. Bomet County is usually characterized by high temperature and humidity between
the months of January and March which was the period for our sample collection. These conditions are favorable for growth and proliferation of aflatoxin producing fungi. It is a common practice for farmers to give
supplementary feeds in form of spoilt grains and commercial feeds to their cattle besides grazing. Fungi may
easily produce toxins in inappropriate storage conditions. It has been reported that environmental temperature,
humidity and moisture content of the feed as well as pH and mechanical damage to cereal grains resulted in
higher AFB1 in animal feeds [19]. Following the consumption of AFB1 contaminated feed by dairy cattle,
AFB1 is converted to AFM1 in the liver and results in contamination of milk of lactating cows with aflatoxin
M1.