Prevalence of antimicrobial residues in preprocessed and processed cows' milk in Trinidad

The prevalences of antimicrobial residues were determined in cows' bulk raw milk from 16 collection centers, in pasteurized milk obtained from sale outlets, and in raw, pasteurized and sterilized milk in the processing line of a plant in Trinidad. The Delvotest SP 5 Pack test kits were used to detect the antimicrobial residues in milk. Thirty-one (10.3%) of 300 bulk milk samples contained antimicrobial residues with penicillin responsible for 90.3% of all the positive samples which originated from 8 (50.0%) of the 16 collection centers. The prevalence of residues in pasteurized milk was 21.3% compared to 8.3% detected in sterilized milk. The difference was not statistically significant (P greater than or equal to 0.05; X-2). Pasteurized milk obtained from sale outlets but originating from two other processing plants had antimicrobial residue prevalence of 0% and 8.3%, respectively. It is concluded that the presence of antimicrobial residues in raw and processed milk in Trinidad could be of public health and economic significance.