Medicine residues are a major food safety issue in milk as they can be potentially hazardous to human health. They can also interfere with the manufacturing process of dairy products by inhibiting yoghurt and cheese started cultures. There are ways to avoid residues in milk, though.
1. Properly train staff
All staff should be trained so that they understand the importance of residue avoidance. Training should be on-going and repeated.
2. Practice an on-farm standard operating procedure
Everyone who carries out a treatment procedure should know the farm’s standard operate procedure. This should be written down and accessible by staff at all times.
3. Identify all treated cows
Herds with poor identity are more likely to have a higher risk of residue failure. For this reason, it is essential that individual cows can be easily identified. Note that ear tags can be problematic, since the milker cannot see them from the milking pit.
4. Mark all cows before treatment is administered
Best practice is to mark all cows before treatment. Some producers label treated cows by putting red spray on their udders.
5. Use only licensed medicines
All medicines used in dairy cows must be fully licensed by the regulatory authority in the country of use.
6. Store medicines correctly
Store medicines in the correct manner according to the data sheet. Any products that have passed their expiry date must not be used and properly discarded.
7. Ensure medicines are correctly labelled
Medicine labels must show the milk withdrawal period. The label should also include information on dose rate, frequency of treatment and mode of administration.
8. Record all treatments
It is a legal requirement to record all treatments given to food-producing animals. All treatments – not just the first and last – must be included.
9. Milk treated cows separately or last
The best course of action is to milk all cows whose milk must be discarded last and/or separately. Doing so will help avoid the accidental transfer of milk that should be discarded.
10. Test the milk of purchased cows
While most farmers buy cows presuming that they are free from medicine residues, it is a good practice to test the cow to be certain.
11. Observe correct withdrawal periods
Farmers must clearly understand and follow the correct withdrawal period. In “off label” situations, it is important to leave interpretation to the prescribing vet or the regulatory authority in your country. If uncertain, use an antibiotic screening test.
12. Separate milking and dry cows
On farms with smaller herds, milking and dry cows may be kept together. This practice should be avoided where treatment is involved.
13. Discard milk from treated cows
Until the end of the appropriate withdrawal period passes, all milk from treated cows must be discarded. While some farmers feel that it is only necessary to discard milk from the treated quarter, this is wrong and can cause residue failures.