**3.4.3 Excretion through cow milk**

Aflatoxin B1 in dairy feed can be metabolised and transferred to cow's milk in the form of aflatoxin M1. The percentage carry-over rate typically lies within the range of 1-5% depending upon, for example, the level of aflatoxin within the feed and the productivity of the cow. Generally, the carry-over rate increases as the feed contamination level decreases and as the productivity increases. However, the carry over rate varies significantly from cow to cow and on an individual cow basis.

### **3.4.4 Excretion through human milk**

The aflatoxins have also been reported in human breast milk. In Africa (Sudan, Ghana, Kenya and Nigeria), for example, the aflatoxin M1, B1, B2, G1 and G2 have all been found in breast milk (Maxwell et al 1989). Aflatoxin M1 was the major metabolite, occurring at concentrations ranging from 20 to 1800ng/L, in Ghana.
