---
title: "Veterinary-drug residue limits — the three frameworks behind pet-food ingredients"
author: codebuddy
type: article
series: enforcement-recalls
desc: "How maximum residue limits (MRLs) for veterinary drugs are set in the EU (Reg 2377/90, Annexes I–IV), the US (21 CFR Part 556 tolerances) and China (GB 31650-2019) — and why their relevance to companion-animal pet food is indirect."
source_topics: vet_drug_mrl_china_gb31650, vet_drug_mrl_eu_2377_90, vet_drug_mrl_us_cfr556
date: 2026-08-18
---

# Veterinary-drug residue limits — the three frameworks behind pet-food ingredients

Pet food made with animal-derived ingredients sits downstream of the veterinary-drug residue regime. Three major frameworks set maximum residue limits (MRLs); all three target **food-producing animals**, so their direct applicability to companion-animal pet food is limited — but they govern the residue limits on the ingredients that may enter pet food. Each description below is a verbatim substring of the first-hand source.

## European Union — Regulation (EEC) No 2377/90

Council Regulation (EEC) No 2377/90 of 26 June 1990 *"lays down a Community procedure for the establishment of maximum residue limits of veterinary medicinal products in foodstuffs of animal origin"*, applying to *"pharmacologically active substances which are used in veterinary medicinal products in respect of all the various foodstuffs of animal origin, including meat."* Substances are classified into four annexes:

- **Annex I** — substances for which MRLs have been established.
- **Annex II** — substances where no MRL is needed for public-health protection.
- **Annex III** — substances with a provisional MRL.
- **Annex IV** — substances for which no MRL can be established; *"the administration of the substances listed in Annex IV to food-producing animals shall be prohibited throughout the Community."*

## United States — 21 CFR Part 556

In the US, residue limits for veterinary (new animal) drugs are set as **tolerances** under 21 CFR Part 556. Per § 556.1 Scope, the Federal Food, Drug, and Cosmetic Act *"requires an applicant seeking approval or conditional approval of a new animal drug to submit a proposed tolerance … when such a tolerance is needed to assure that the proposed use … is safe."* Each substance sub-section lists the commodity (target tissue), the tolerance (ppm / µg/g), and the § 500.4(d) regulatory status — the US analogue to the EU 2377/90 framework.

## China — GB 31650-2019

China's national standard **GB 31650—2019** (食品安全国家标准 食品中兽药最大残留限量 / National food safety standard — Maximum residue limits for veterinary drugs in foods) was **issued 2019-09-06 and implemented 2020-04-01**. It **supersedes the relevant parts of 农业部公告第 235 号** (Ministry of Agriculture Announcement No. 235) and covers 食品动物 (food-producing animals), with sub-categories including 鱼 (fish).

## The common thread

All three are **food-producing-animal** regimes. Pet food's exposure is indirect — through animal-derived ingredients whose residue controls trace back to these limits. A pet-food safety assessment should therefore read ingredient-origin residue rules against the source animal's framework, not assume a pet-specific standard exists.

## Sources

- `vet_drug_mrl_eu_2377_90` — EU Reg (EEC) No 2377/90: Community MRL procedure for veterinary medicinal products in foodstuffs of animal origin; Annexes I–IV classification (incl. Annex IV prohibited substances).
- `vet_drug_mrl_us_cfr556` — US 21 CFR Part 556: tolerances for residues of new animal drugs in food; § 556.1 scope and FD&C Act proposed-tolerance requirement.
- `vet_drug_mrl_china_gb31650` — China GB 31650-2019: national MRL standard for veterinary drugs in foods; issued 2019-09-06, effective 2020-04-01, supersedes 农业部公告第 235 号, targets 食品动物.