Analysis of veterinary drug residues
New complementary class testing
Aug 2026. The simultaneous analysis of substances with different chemical and physical characteristics is challenging and usually results in a compromise, for example in terms of sensitivity and quality. The new complementary class testing strikes precisely this balance and enables the sensitive and quantitative analysis of 95 selected veterinary drug residues using high-resolution mass spectrometry with just a single sample preparation.
Veterinary drugs – more than just antibiotics
In recognition of the crisis of antibiotic resistance, the aim is to reduce the use of antibiotics in food production to a minimum. Positive trends are emerging, and since 2016, more antibiotics were handled to humans than to animals in Europe (mg per kg biomass).
However, it is not just antibiotics that are used for the treatment of diseased farm animals. Antiparasitic drugs, anti-rheumatic drugs, sedatives, as well as preventative vaccinations, also play a significant, and in some cases growing, role. Only authorised products are suitable. After treatment, a waiting period must be observed to allow the animal to metabolite the substances before it can be used for food production again.
Commission Regulation (EU) No 37/2010, amongst other sources, defines which of these substances are permitted and which are prohibited as well what kind of concentrations they are allowed as contaminant in food of animal origin.
It is therefore mandatory to be certain about the quantification of veterinary drugs to ensure food safety and animal welfare by enabling the detection of residues at trace levels. In addition, reliable concentration measurements in animal feed are necessary to enable accurate dosing and to prevent cross-contamination.
The new complementary class testing
The new complementary class testing offers a solution for the reliable quantification of selected antibiotics, antiparasitic substances and sedatives in food, as well as antibiotics and antiparasitic substances in animal feed on contaminant level. A key feature is that substances from sulfonamides, macrolides, lincosamides, benzimidazoles, phenylureas and sedatives, as well as salicylanilides and other antiparasitic substances, can be analysed simultaneously with just a single sample preparation. The substance classes were selected based on their relevance and applications, but also in such a way that only minimal analytical compromises were necessary to achieve highly sensitive quantification. As part of this, 17 new substances were added to the portfolio. The toolbox principle gives you the freedom to tailor your analysis exactly to your needs. Select from the named substance classes with maximum flexibility while benefiting from a single sample preparation. Focus on the parameters that matter most to you and take advantage of attractive cost savings compared to conventional individual testing.
More than a compromise
Multi component analyses, such as multiclass screening, face the challenge of achieving results of equivalent quality for all substances. The new complementary class testing approach, supported by high-resolution mass spectrometry (LC-HRMS/MS), delivers highly sensitive, selective and reliable quantitative results for all the substances while meeting current regulatory requirements. This allows a reduction of Limits of Quantification (LOQs) and ensures full compliance with the latest requirements guidelines. The method has been accredited and fully validated in accordance with Implementing Regulation (EU) 2021/808, making it suitable for official controls.
Which substances should be analysed?
The complementary class testing can be applied to animal-based foods such as meat, fish and seafood, eggs, dairy products and honey; drinking water for animals can be also analysed.
The following table provides an overview of the substance classes available for analysis and their recommended test strategy for the most common animal-based foods. Additionally, the analyses of contaminations in feeds are recommended.
| Poultry | Eggs | Swine | Cattle | Milk and dairy products |
Fish | Feed | |
| Salicylanilide and other antiparasitics |
X | X | X | X | X | X | X |
| Benzimidazoles | X | X | X | X | X | X | X |
| Makrolides and Lincosamides |
X | X | X | X | X | X | X |
| Sulfonamides | X | X | X | X | X | X | X |
| Phyenylureas | X | X | X | X | |||
| Sedatives | X | X | X |
This table provides a recommendation based on the substance classes included in the complementary class testing. Other substance classes may also be relevant, depending on regulatory requirements or their usage during production. A wide range of additional methods enables the reliable detection of commonly used antibiotics such as tetracyclines and quinolones, as well as prohibited substances including hormones and hormone analogues. Please contact us for further advice.
Further benefits at a glance
- Long standing expertise in analysing and evaluating veterinary drug residues
- Individual expert advice for your testing strategy
- A high level of laboratory automation: dynamic laboratory capacity helps you achieve rapid results, even during a crisis
Get in touch
Would you like to find out more about our testing solutions, or do you need tailored analytical support? Contact us today to get in touch with our experts.
Written by:
Mareike Rathke
Eurofins WEJ Contaminants GmbH