Abstract

Objective: This study investigate the influence of season on the occurrence of adulteration by chemical preservatives and antibiotic residues (beta-lactam, tetracycline and sulfonamides) in the raw milk in the main towns of Khartoum State, Sudan. Methods: The milk samples (n = 270) were randomly collected from farms (90 samples), groceries (90 samples) and vendors (90 samples) during late summer and winter seasons, 135 samples during each season. The samples were placed in cool cracked ice and transported immediately to the laboratory for analysis. Results: Data revealed a high presence of the added water in the milk collected from vendors during late summer season (7.70 +- 9.46%). Also, hydrogen peroxide, starch and formalin were detected only in the milk obtained from vendors. However, the higher percentages of salt (32%) and ammonium sulphate (28%) were obtained in the milk samples collected from the groceries during late summer season, while the occurrenc of ammonium sulphate was 26% in the samples collected from vendors during winter season. On the other hand, 93% of the milk samples examined during late summer season were positive for the occurrence of antibiotic residues compared to 55% that was detected during winter season. The highest percentage of antibiotic residues (26%) was found in milk from groceries during the winter season. Milk samples from vendors during late summer season contained beta-lactam, tetracycline, and sulfonamide in 19%, 13%, and 1% of samples, respectively, while these figures were 20%, 2%, and 3%, respectively, during winter season. Conclusions: The addition of water followed by the presence of salt and antibiotics are the most adulterants found in raw milk sold in Khartoum State especially from vendors during late summer season.