Assessment of Microbial Loads and Antibiotic Residues in Milk Supply in Khartoum State, Sudan

This study was conducted to evaluate the quality of milk supplied to consumers from 2 sources, which include farms and sales points in Khartoum State. Raw milk samples (72 samples) were collected from Khartoum North (36 samples) and Khartoum (36 samples). All milk samples were analyzed for total bacterial counts (TBC), coliform counts and psychrotrophic counts as well as measuring temperature and acidity. Moreover, antibiotic detection was performed using both Delvotest and Modified one plate test. The results indicated that the levels of TBC, coliform counts and psychrotrophic counts were ranged between log10 8.279 to log10 11.491 cfu mL-1, log10 3.845 to log10 9.179 cfu mL-1 and 0 to log10 1.690 cfu mL-1. The acidity and temperature of milk samples were 0.11-0.3 and 13-30.7 C, respectively. In the present study, it was found that the mean level of TBC, coliform counts and acidity of milk samples from sales point`s samples were found to be log10 11.136 0.215 cfu mL-1, log10 8.802 0.254 cfu mL-1 and 0.219 0.048, respectively. These values were found to be higher than the values, which recorded for the milk samples that were collected from the farms (log10 9.089 0.281 TBC, log10 4.789 0.340 coliform, 0.158 0.032 acidity). However, psychrotrophic counts revealed higher mean value (log10 0.227 0.523 cfu mL-1) for farms samples compared to sales points samples (log10 0.069 0.238). Antibiotic residues were detected in 28 (38.9%) of examined milk samples, 17 (23.6%) of these were in Khartoum North and 11 (15.3) were in Khartoum. On the other hand the milk samples from sales points had the highest percent of the antibiotic residues 20 (55.6%) compared to those detected in the farms 8 (22.2%). The 28 (38.9%) milk samples that showed positive results were confirmed for the presence of antibiotic residues after heat treatment and 26 (92.9%) of them remained positive.