because.a-ZAL can been detected in the final product when used as a
growth promoter for livestock (Stephany and Adré, 1999).
Once
ingested, a-ZAL could be metabolized into its diasteromer b-ZAL
and, to a lesser extent into ZAN and conjugated with sulfonic or
glucuronic acid.
This reduces bioactivity, as only free forms are biologically
active, and facilitates urinary excretion.