Determination of antibiotic residues in raw cow’s milk sold in two dairies in the Koulikoro Region using the HPLC technique

Abstract

Veterinary treatments, mainly antibiotics, used for therapeutic or prophylactic purposes in dairy farming can be the cause of the presence of antibiotic residues in milk. However, these residues constitute a major health concern for consumers. For the dairy industry, whose objective is to have a raw material suitable for processing, it is necessary to screen for antibiotic residues in milk at each collection. This study is based on two parts, a survey of seventy people (10 practicing veterinarians and 60 milk producers) to describe the main molecules of antibiotics used in dairy cattle farming in the two basins of Tienfala and Kasséla in the Koulikoro region, and a search for residues by Delvotest SP with confirmation of positive samples by liquid chromatography (HPLC). To this end, sixty (60) samples of raw milk were collected in two sampling campaigns per site carried out 15 days apart. All samples were analyzed using the Delvotest SP rapid detection of antibiotic residues in milk kit first before being analyzed by liquid chromatography (HPLC) for positive samples. The results of the surveys revealed the predominance of three pathologies within dairy herds: diarrhoea, mastitis and pulmonary infections with a combination of several antibiotics belonging to five (5) different families of antibiotics. Of the 60 samples submitted for analysis, 38 were found to be positive with Delvotest SP, i.e. a contamination rate of around 63.33%. Of the 38 samples positive to the rapid test, 26 responded positively to confirmation by liquid chromatography, i.e. a rate of 68.42% with mainly four antibiotics belonging to the families of β-lactams and tetracyclines. The results of the study effectively prove the effective presence of antibiotic residues in raw cow's milk from the mini-dairies of Kassela and Tienfala. They thus characterize current practices in the treatment of dairy cattle with antibiotics in the farming areas studied. Compliance with withdrawal periods with the elimination of milk from treated cows must be obtained by raising the awareness of producers by animal health professionals.