Analysis of antibiotic residues in milk from smallholder farms in Kenya
Keywords:
Antibiotic residues, milk, Kenya, Delvotest®, Trisensor, screening tests, sulfonamides, tetracyclines,, beta-lactams, HPLC.Abstract
The aim of this study was to determine the occurrence of antibiotic residues in Kenyan smallholder farm
milk using screening tests, and to identify the antibiotic residue group. A total of 480 milk samples were
analyzed. All samples were analyzed with the Delvotest® screening test. A Hundred and fourteen (24%)
samples were positive, 71 (15%) unclear and 295 (61%) negative. Sixty-two samples were further tested
with the group specific Trisensor test. Twenty four percent (15/62) were positive. This indicated that by
estimation, 9% of all the 480 samples have been positive with the Trisensor test and 5% would have
contained beta-lactams, 2.5 % sulfonamides and 0.6 % tetracyclines. Samples with a positive Trisensor
test results were further analyzed with HPLC but no antibiotics could be identified. Seventy six percent of
the Delvotest® positive samples were negative in Trisensor test. Microbiological inhibitor methods are
demanding for the sample conditions and were found not to be best suited to the conditions encountered
in smallholder farms in Kenya. The results indicate that antibiotic residues are found in milk produced on
small scale farms in Kenya and suggest that training is needed on the use of veterinary drugs.
