This is because most animal feed is produced in shared factories, and residues can be carried over from one batch containing antibiotics to a subsequent batch of non-medicated feed – a problem known as cross-contamination.

In their latest research, Dr Ursula Vincent and her team at the European Commission’s Joint Research Centre – or JRC – have developed a new analytical method that can detect trace levels of antibiotics in livestock feed. Their work is bringing us one step closer to safer food systems and more responsible antibiotic use.

The JRC team focused on five antibiotics commonly used in livestock: apramycin, paromomycin, tobramycin, neomycin and spectinomycin. Detecting these drugs at low levels in non-medicated feed is challenging, because of the many interfering compounds that are naturally present in feed.

By analysing previous research, the JRC team found that there was a need for a reliable new method for detecting these antibiotics in animal feed, especially when only trace amounts are present. To address this urgent need, the team set out to design and validate a precise, practical, and sensitive detection method. Their approach uses liquid chromatography–tandem mass spectrometry, which is a gold standard in the analysis of contaminants (or residues) in feed.

The team optimised the sample preparation process, fine-tuning the pH levels and using high-efficiency extraction cartridges.

When testing the new method, the JRC team achieved consistently high extraction rates and could accurately detect trace amounts of antibiotics, making it suitable for enforcing EU limits on feed cross-contamination. Furthermore, the method proved reliable across five common types of livestock feed: for cows, pigs, sheep, poultry, and rabbits.

By providing a reliable way to detect trace antibiotic residues in feed, the JRC’s method strengthens our ability to enforce EU regulations. This is an essential step in limiting unnecessary antibiotic exposure in animal farming and curbing the spread of antimicrobial resistance, to protect both animal and human health.