Antimicrobial Agents Detected In Marketed Milk In Kenya

Abstract

Drug residues in foods are a major public health concern in many countries, especially where most food sales bypass official quality assurance channels. In common with many tropical countries, sales of unpasteurized milk in Kenya account for over 85% of marketed milk. This milk is either sold directly from producers to consumers or via various cadres of informal market agents. Besides residues that may arise from lack of adherence to withdrawal times following cow therapy, there have been concerns that some antimicrobial agents may be added to informally marketed milk to extend its shelf life. As part of a large study to assess public health hazards associated with marketed milk, samples were collected seasonally between January 1999 and January 2000 from raw (unpasteurized) milk consuming households and informal market agents of various cadres. Pasteurised milk samples were also collected from retail points and tested for comparison. All samples were screened for antimicrobial residues using charm AIM-96 and Charm-ROSA (Charm Sciences Inc, USA) tests. The former detects a wide range of anti-microbials, and the latter detects β-lactams and tetracyclines specifically, at levels above maximum residue limits (MRLS) recommended by the European Union (EU). The Charm-AIM screening test showed that 9.4% and 5.7% of samples from consumer households and market agents had antimicrobial residues above EU MRLS, respectively. It was concluded that antimicrobial residues were more likely to have originated at farm-level than because of poor market handling practices.