Antibiotic Residues in Milk Supplies in Zimbabwe

Area of Science:

• Veterinary Medicine
• Food Safety
• Microbiology

Background:

• Antibiotic residues in raw milk pose a significant food safety concern.
• Contamination can arise from therapeutic treatments in dairy herds.
• Monitoring antibiotic residues is crucial for public health and trade.

Purpose of the Study:

• To assess the prevalence of antibiotic residues in raw milk from Zimbabwean producers.
• To determine the necessary withholding period for specific antibiotic treatments to ensure milk is residue-free.

Main Methods:

• Collected 73 raw milk samples from three Dairy Marketing Board centers in Zimbabwe (Jan-Feb 1988).
• Utilized the Delvotest-P ampoule test to detect penicillin and other antibiotic residues.
• Conducted an antibiotic depletion study with 23 cows treated with a streptomycin-penicillin mixture.

Main Results:

• 5.5% of samples contained penicillin residues above the threshold (≥0.005 I.U./ml).
• 2.8% of samples showed residues of antibiotics other than penicillin.
• A withholding period of 7-8 days was required for the streptomycin-penicillin product to achieve residue-free milk.

Conclusions:

• Antibiotic residues are present in raw milk from Zimbabwe, necessitating improved management practices.
• A 7-8 day withholding period is crucial for intramammary antibiotic treatments to prevent residue contamination.
• Continued surveillance and adherence to withdrawal periods are essential for milk safety.