REMOVAL OF SULFAMETHAZINE FROM ARTIFICIALLY CONTAMINATED MILK BY ULTRAFILTRATION

The effect of discontinuous diafiltration (DD) on removal of sulfamethazine (SMZ) from raw whole and homogenized milk was studied. Milk was artificially contaminated with concentrations of SMZ varying from 20 to 90 μg/L. A hollow-fiber membrane with a molecular weight cut-off of 10,000 daltons was used for all experimental runs at 55C. The removal pattern of SMZ was influenced (P<0.05) by both the initial concentration and the homogenization process. Homogenization increased the removal of SMZ from milk. The DD process resulted in concentrates with residual levels of SMZ <10 μg/L (FDA action level). SMZ was not detected in reconstituted retentates resulting from milk originally up to 30 μg/L.