An anti-microbial composition for treating animal feed, comprising: 1 to 90 wt.% based on the total weight, of a Ci to C24 organic acid, 1 to 90 wt.%), based on the total weight, of trans-2-hexenal provided it constitutes at least 5 wt.% of the organic acid and aldehyde mixture, 0 to 50 wt.%) based on the total weight of terpenes, 0 to 20 wt.%) based on the total weight of a surfactant, and water.
