Antibiotics in poultry production: withdrawal periods, residues and how they are controlled

One question comes up in almost every conversation about chicken: is it full of antibiotics? The question is fair, but the way it is framed pushes towards a wrong answer in either direction. A farm is not choosing between using medicine and not using it; the bird is a living animal that gets sick, and withholding treatment is not a virtue but a welfare problem. The right question is this: if a medicine is used, what guarantees that its trace does not reach the meat at slaughter? The answer is a full control system, and every link in it has a name, a reference and a laboratory that verifies it. This lesson takes that system apart, link by link.

First, put the term in its place. Residues are not the medicine given to the bird; they are what may remain of it, or of its breakdown products, in the tissues after treatment ends. They are invisible and imperceptible — no colour, no smell, no taste — and no buyer can detect them by looking, washing or sniffing. That is precisely why they are not managed at the shelf or in the kitchen, but weeks earlier: on the farm, in the treatment log, and in the recorded date set for slaughter.

Three very different uses under one name#

The biggest confusion here is that the word antibiotic is used for three things that differ completely in purpose, dose and regulatory status. The Codex Alimentarius Code of Practice to Minimize and Contain Foodborne Antimicrobial Resistance (CAC/RCP 61-2005) separates them in explicit definitions:

• Treatment: giving the antimicrobial to a bird or flock with a clinically diagnosed infectious disease — the direct medical use.
• Prevention: giving it to healthy birds considered at risk of infection, or to contain the spread of a disease already diagnosed within the group before it reaches the rest.
• Growth promotion: using antimicrobial substances to increase the rate of weight gain or feed-conversion efficiency by other than purely nutritional means — and the code states explicitly that the term does not apply to treating or preventing disease, even when an incidental growth response occurs.

The distinction is not academic. The same code holds that the use of veterinary antimicrobial drugs for growth promotion, where they belong to classes used in human medicine, should be terminated or phased out in the absence of a risk analysis. The World Health Organization then went further in its 2017 guidelines on the use of medically important antimicrobials in food-producing animals, recommending a complete restriction on the use of all classes of medically important antimicrobials for growth promotion, and an overall reduction in their use in these animals. The regulatory direction worldwide is clear: treatment stays, growth promotion goes.

From the dose to the plate: how a withdrawal period is built#

The central link in the whole system is called the withdrawal period: the time that must pass between the last dose of a medicine and the slaughter of the bird. It is not an estimate or a custom, but a figure derived arithmetically from a chain that precedes it. The chain begins with a safety evaluation which — per the Codex code — must include microbiological effects, such as the potential biological impact on the human intestinal flora, alongside toxicological and pharmacological effects. From that evaluation an acceptable daily intake (ADI) is derived, and on it a maximum residue limit (MRL) is built for each relevant food: meat, milk, eggs, fish and honey. The code states the purpose of that limit in a very practical sentence: MRLs are necessary so that officially recognised control laboratories can monitor that veterinary antimicrobial drugs are being used as approved. The limit is not only a toxicological red line; it is an inspection tool.

On that basis a withdrawal period is set for each veterinary drug individually, so that producing food in compliance with the MRL becomes possible. The code lists the factors that must be taken into account when setting it:

• The MRL established for that specific drug.
• The pharmaceutical form — a product given in drinking water does not behave like an injection.
• The target animal species; what applies to one species does not transfer automatically to another.
• The dosage regimen and the duration of treatment.

A withdrawal period is a date, not a feeling. The bird does not look different on its final day than on the day after, so the real control is not observation but the record: drug name and batch number, date of administration, the group treated, the quantity and duration, and the corresponding withdrawal period. That record — among those the Codex code recommends keeping — is what turns a decision inside a shed into something a third party can verify later.

What Saudi Arabia actually requires at the border#

In the Kingdom, this system appears in a document anyone can read: the Conditions and Requirements for Importing Food to the KSA, issued by the Saudi Food and Drug Authority, which contains the model Health Certificate for Export of Poultry Meat and Poultry Meat Products to the KSA. The certificate is a list of attestations signed by the official body in the country of origin, and one of them addresses this exact file: that good veterinary practices have been applied in the use of veterinary medicines — the form says explicitly, including growth promoters — and agricultural chemicals in live animals, and that any residues of hormones, antibiotics, pesticides, heavy metals or any other pollutants in poultry meat and its products comply with SFDA.FD 382/2019, GSO 2481, GSO 1016 and GSO CODEX STAN 193.

The attestation becomes clearer when read alongside the rest of the same certificate, which shows that residues are not an isolated clause but part of an integrated health file that also requires:

• That the birds were slaughtered in an abattoir approved and supervised by the competent authority of the exporting country, and approved by the SFDA.
• That they underwent ante-mortem and post-mortem inspection by veterinarians assigned by the competent authority of the country of origin.
• That the establishment is subject to inspection by the competent authority and operates a food-safety management system based on HACCP principles or an equivalent.
• That the birds were not fed on processed animal protein, excluding fishmeal.
• That the meat is accompanied by a consignment certificate for halal slaughter per GSO 993, issued by a halal certification body recognised by the Authority's Halal Center.

The national AMR action plan 2022-2025#

The MRL handles half the question: what reaches your plate. The other half is antimicrobial resistance — the fact that overusing these drugs, in human and veterinary medicine alike, pushes bacteria to develop resistance that makes treatment less effective later. This is why the Public Health Authority (Weqaya) issued the Kingdom's Antimicrobial Resistance Action Plan 2022-2025: five objectives branching into thirteen initiatives and forty-four activities, distributed across responsible bodies including the Ministry of Environment, Water and Agriculture, the Saudi Food and Drug Authority and the Ministry of Health.

What concerns the poultry sector in that plan is spelled out. Under Objective 4 — optimising the use of antimicrobial medicines in human and animal health — the third initiative is to ensure prudent use in terrestrial and aquatic animals and agriculture, and it breaks down into activities that include producing a comprehensive annual list of restricted antimicrobials consumed in the animal-health sector, especially in food-producing animals; establishing an antimicrobial prescription and utilisation monitoring system for that sector; and developing national guidelines for antimicrobial use by species: food animals, pets and aquatic animals. Objective 2 widens surveillance to humans, animals, food and the environment, and its text names antimicrobial residues in food and animal feed explicitly. Alongside it runs an already-active surveillance activity: detection of salmonella, campylobacter and total bacterial count in poultry across all regions of the Kingdom.

Prevention is cheaper than treatment — literally#

The shortest route to using fewer antibiotics is not banning them but reducing the need for them. The Codex code puts this in policy terms: national governments, in cooperation with animal and public-health professionals, should adopt a proactive approach to promoting prudent use, and the other elements of the national strategy should include good animal husbandry practices, vaccination policies and the development of animal health care at farm level — all of which reduce the prevalence of disease requiring antimicrobial treatment in the first place. Put plainly: a clean shed, a vaccinated flock and a visitor who changes footwear at the gate are all tools for lowering drug use, exactly as much as the drug itself is.

The code also places direct operational duties on the producer, the most relevant here being: to comply with the recommended withdrawal periods so that residue levels in animal-derived food do not present a risk to the consumer; to comply with the storage conditions on the approved product label; not to use out-of-date veterinary antimicrobials and to dispose of unused ones as the label provides; and to inform the veterinarian in charge of the unit of recurrent disease problems.

What this means for you, as a buyer or a consumer#

For a wholesale buyer or a restaurant owner, the takeaway is practical: treat this as a question of documents, not a question of trust. An importing supplier can give you a copy of the health certificate accompanying the consignment, and a local supplier can give you veterinary-residue laboratory reports if those are part of its quality system. Once the request is written into the supply agreement, it stops being a courtesy and becomes a condition. For a consumer at home the takeaway is different: residues are not yours to manage. What you manage in your kitchen is bacteria — cooking to a safe internal temperature and preventing cross-contamination — and those steps protect you whether the bacteria in question are susceptible to antibiotics or resistant to them.

Three questions summarise the assessment of any poultry supplier on this file: can you give me the health certificate or certificate of conformity accompanying the consignment? Do you have veterinary-residue test results, and who issued them? And does the product come from an establishment running a HACCP-based food-safety system? The answers to those three reveal the maturity of a supplier's quality system better than any quick site visit.