Any veterinary medicinal product intended for food-producing animals has to clear a gate that does not exist in human medicine: the residue assessment. EU law requires that foodstuffs such as meat, milk and eggs do not contain residues of veterinary medicines at levels that could harm the consumer. That requirement is delivered through maximum residue limits and the withdrawal periods derived from them, and it shapes the development programme long before authorisation.
The legal architecture
Regulation (EC) No 470/2009 lays down the rules and procedures for establishing maximum residue limits for pharmacologically active substances in foodstuffs of animal origin. The Committee for Medicinal Products for Veterinary Use at the European Medicines Agency is responsible for recommending them, and they become legally binding food safety standards once adopted by the European Commission. Measures on management and control in foodstuffs of animal origin follow from the same framework.
No MRL, no product
The sequencing matters. A pharmacologically active substance intended for use in food-producing species needs an established maximum residue limit, or a determination that one is not required, before a product containing it can be authorised for those species. For a company developing a new substance, the residue work is therefore not a downstream regulatory formality. It is a gating item that has to be planned, resourced and started early, and it draws on metabolism, depletion and analytical method work that takes time to generate.
From MRL to withdrawal period
The withdrawal period stated in the marketing authorisation is the minimum period between the last administration of the product to an animal and the production of food from that animal, which under normal conditions of use is necessary to ensure that the food does not contain residues in quantities harmful to public health. It is derived from residue depletion data assessed against the maximum residue limit, per species, per tissue or commodity, and per formulation and route.
Two consequences follow. A change to formulation, dose, route or species is potentially a change to the withdrawal period, which makes residue data a live lifecycle concern rather than a closed file. And the withdrawal period is the single piece of product information most directly relied on by the farmer and the food chain, so its clarity in the product literature is a practical safety matter.
Where this intersects with the cascade
When a product is used under the cascade in food-producing animals, a withdrawal period still has to apply. Regulation (EU) 2019/6 sets out how it is derived where the product carries none for the species concerned, including default multipliers and minimum periods. Companies should expect questions from veterinarians about cascade use of their products and should have a considered position rather than an improvised one.
How PQRA helps
PQRA advises on residue strategy for veterinary products intended for food-producing species: assessing whether a maximum residue limit exists or is needed, planning the residue and depletion programme, supporting withdrawal period justification in the dossier, and managing the lifecycle consequences when formulations, doses or species change. We also help companies communicate withdrawal periods clearly in product information and in the field.
To discuss residue and withdrawal period strategy, contact PQRA.
No responses yet