INTERNATIONAL PROGRAMME ON CHEMICAL SAFETY
WORLD HEALTH ORGANIZATION
TOXICOLOGICAL EVALUATION OF CERTAIN
VETERINARY DRUG RESIDUES IN FOOD
WHO FOOD ADDITIVES SERIES 41
The 50th meeting of the Joint FAO/WHO Expert
Committee on Food Additives (JECFA)
World Health Organization, Geneva 1998
The Committee examined the results of studies of antimocrobial
activity in vitro in which relevant gut microflora were used to
calculate ADIs for some of the antimocrobial agents that were
reviewed. The equation used for deriving the ADIs is based on that
described in the report of the forty-seventh meeting of the Committee
(Annex 1, reference 125).
The upper limit of the ADI was derived as follows:
Upper limit MIC50 (µg/g) × MCC(g)
of ADI =
(µg/kg bw) FA × SF × BW(kg
MIC50 = The minimum concentration of an antimicrobial drug that
completely inhibits the growth of 50% of cultures of a given
microorganism, as judged by the naked eye, after a given
period of incubation. For the purposes of the evaluation,
the MIC50 value is the mean MIC50 value(s) for the
strain(s) of the relevant species tested. Alternatively,
the lowest MIC50 value for the most sensitive species can be
MCC = Mass of colonic content; a value of 220 g is used.
FA = Fraction of an oral dose available to act upon
microorganisms in the colon
SF = The safety factor used to account for uncertainty about the
amount and relevance of data for MIC values available for
review; may range from 1 to 10, a value of 1 being used when
extensive, relevant microbiological data are available.
BW = Body weight; a value of 60 kg is used.