The mold spore plate count often has been used to estimate the potential ri
sk that feed may pose to poultry health. This measurement, however, was fou
nd to be highly variable between batches of feed manufactured at differenti
al geographical locations and multiple samples of the same batch of the sam
e batch of feed. A marked reduction or elimination of viable spores produce
d by numerous mold genera was found to be associated with the pelleting pro
cess. However, re-contamination of manufactured feed, within 2 days followi
ng the pelleting process, with spores from the environment results in a mar
ked increase in mold spore counts in feed and further contributes to the hi
gh variability associated with this measurement. Given the influence of fac
tors such as source of feed ingredients, pelleting, and re-contamination of
feed, the mold spore plate count is inappropriate as a means of assessing
the mycological status of feed and the risks that the feed may pose to poul
try health.