21 C.F.R. § 556.283 – Florfenicol.

(a) Acceptable daily intake (ADI). The ADI for total residue of florfenicol is 10 µg/kg of body weight per day.
(b) Tolerances. The tolerances for florfenicol amine (marker residue) are:
1. (1) Cattle.
  1. (i) Liver (target tissue): 3.7 ppm.
  2. (ii) Muscle: 0.3 ppm.
2. (2) Swine.
  1. (i) Liver (target tissue): 2.5 ppm.
  2. (ii) Muscle: 0.2 ppm.
3. (3) Catfish. Muscle (target tissue): 1 ppm.
4. (4) Freshwater-reared warmwater finfish (other than catfish) and salmonids. Muscle/skin (target tissue): 1 ppm.
(c) Related conditions of use. See §§ 520.955, 522.955, 522.956, and 558.261 of this chapter.