The effects of the additive on the intestinal microflora
should be evaluated by enumeration of the routinely cultivable
microbial groups in the faecal flora (i.e., coliforms,
enterococci, clostridia, etc). Also, the intestinal survival and
the rate of disappearance from the faeces after withdrawal of
the additive should be monitored. In certain cases, effects on
the shedding of human enteropathogens may be required,
especially if the product is intended for companion animals.