StacksVerified U.S. regulatory reference

21 CFR §556.428

Verified against eCFR.gov as of June 20, 2026View official text on eCFR.gov ↗
  1. (a)Acceptable daily intake (ADI). The ADI for total residue of narasin is 5 µg/kg of body weight per day.
  2. (b)Tolerances. The tolerance for narasin (marker residue) is:
    1. (1)Chickens. Abdominal fat (target tissue): 480 ppb.
    2. (2)[Reserved]
  3. (c)Related conditions of use. See §§ 558.363 and 558.364 of this chapter.