Antibiotic Milk Test Methods for Dairy Laboratories
                     Antibiotic Milk Test for Dairy 
Quality Control
Understanding Residue Screening in Milk
LABTEK SERVICES LTD
ABOUT US
Supporting Dairy 
& Food 
Laboratory 
Testing
Established in 1987, Labtek Services 
Ltd delivers laboratory solutions for 
dairy and food industries, supporting 
farms, processors, and QC 
laboratories with reliable 
ANTIBIOTIC MILK TEST solutions 
Antibiotic Residue Testing Technical Guidance and testIinnsg teruqumipemnetnatt.ion
Screening products and Practical support for Reliable tools for consistent, 
related equipment for dairy laboratory workflows accurate results
QC
Why Test Milk for Antibiotic 
Residues?
Antibiotic residues can enter milk when treated animals return to the milking 
herd before the required withdrawal period ends. Screening protects quality at 
every stage.
Screen Raw Milk
Identify contaminated loads before they enter processing
Protect Fermentation
Safeguard cheese, yogurt, and cultured product quality
Support QC
Maintain consistent quality standards across batches
Flag for Review
Identify samples requiring further investigation
Where Residues Enter the Supply Chain
Understanding common risk points helps prevent testing failures before they occur.
Key Prevention Principle
Clear animal identification and consistent on-farm procedures are the most effective tools for reducing antibiotic 
residue testing failures. Communication between farm staff and quality teams is essential.
Treated animals must be clearly marked and milk withheld for the full withdrawal period before re-entering the 
milking herd.
REGULATORY STANDARDS
Understanding 
Maximum Residue 
Levels
MRL (Maximum Residue Level) is the 
regulatory limit established for a specific 
veterinary drug residue in food. Test 
sensitivity must match the antibiotics 
being monitored.
Antibiotic-Specific Limits Beta-Lactam Group 1 ppb = 1 Part per Billion
Different antibiotics carry different Penicillin G is a key member; Understanding target residue and 
MRLs — testing must be targeted sensitivity requirements vary by required sensitivity guides test 
accordingly compound selection
Two Main Testing Approaches
The right method depends on speed requirements, target antibiotics, and testing workflow.
Microbial Inhibitor Tests Immune-Receptor Tests
Broad-spectrum screening for multiple antibiotic groups. Targeted, rapid screening for specific antibiotic groups.
• Examples: Delvotest SP-NT, Eclipse formats • Lateral-flow devices deliver results in minutes
• Requires incubation period • Useful when fast decisions are required
• Ideal for comprehensive incoming milk screening • Designed for specific antibiotic classes
Controls Improve Test Confidence
Running controls alongside samples verifies that the testing process is functioning correctly and results are reliable.
Negative Control Positive Control
A sample without the target antibiotic. Should Contains a known target or control material. Should 
produce a passing result, confirming normal test produce a failing result, confirming the detection 
performance and absence of interference. system is working as expected.
Include both controls in each testing run to validate the method before interpreting sample results.
INSTRUMENTATION
Incubator 
Readers for 
Easier Results
Modern readers combine incubation 
and result reading in one 
streamlined workflow, reducing 
interpretation uncertainty.
Labtek's COMET and IRIS systems 
support different antibiotic testing 
applications.
Automated Reading Consistent Results Digital Recording
Removes subjectivity from Standardized reading across Results can be stored or 
color-change interpretation operators and shifts communicated electronically
What to Do After a Failed Screening Test
Follow a structured investigation process to confirm results and take appropriate action.
Confirm
Send sample to 
accredited lab for ID 
and quant
Take Action
Re-Test Follow site quality 
Repeat screening procedure for non-
with appropriate compliant milk
controls
A rapid screening result is considered presumptive and may require confirmatory testing depending on the situation and regulatory requirements.
Thank You
Supporting better dairy quality control — from farm to finished product.
Laboratory Products Testing Solutions
Reliable testing tools for Antibiotic residue screening 
every QC environment for dairy processors
Technical Support
Expert guidance from Labtek's experienced team
Labtek Services Ltd — labtekservices.co.uk