The Food and Drug Administration (FDA) has announced the availability of revised draft guidance related to the evaluation and safety of veterinary drug residues in human food. Both sets of guidance are part of the agency’s efforts under the Registration of Veterinary Medicinal Products to harmonize technical requirements for the approval of veterinary medical products in the European Union, Japan and the United States.

The guidance titled “Studies to Evaluate the Safety of Residues of Veterinary Drugs in Human Food: General Approach to Establish a Microbiological Acceptable Daily Intake (ADI)” offers a plan for assessing “the human food safety of residues from veterinary antimicrobial drugs with regard to effects on the human intestinal flora.” To this end, the guidance (i) “outline[s] the steps in determining the need for establishing a microbiological [ADI]”; (ii) “recommend[s] test systems and methods for determining no-observable adverse effect concentrations (NOAECS) and no-observable effect concentrations (NOAELs) for the endpoints of health concern”; and (iii) “recommend[s] a procedure to derive a microbiological ADI.” The agency will accept comments on the revisions at any time.

FDA has also issued draft guidance titled “Studies to Evaluate the Safety of Residues of Veterinary Drugs in Human Food: Genotoxicity Testing,” which revises previous recommendations concerning “a second test to evaluate the potential of a chemical to produce chromosomal effects.” Under the draft guidance, tests to determine whether this potential exists can now take three forms: (i) “an in vitro chromosomal aberrations test using metaphase analysis”; (ii) “an in vitro mammalian cell micronucleus test”; or (iii) “a mouse lymphoma test.” The agency will accept comments on the draft guidance until May 6, 2013. See Federal Register, March 5, 2013.