الفهرس 
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Abstract
This study was carried out on 90 milk samples (55 raw cow’s milk samples and 35 heat treated milk samples) which collected during the period from October 2013 to March 2014 to investigate the Prevalence of β-lactams and Tetracyclines residues in milk. Delvotest® SP NT and Betastar® combo HS kits were used as qualitative screening tests. Positive screened milk samples analyzed by using High Performance Liquid chromatography (HPLC) for detection of Ampicillin, Penicillin G, Amoxicillin, Tetracycline and oxytetracycline antibiotic residues. Incidence of antibiotic residues in raw milk samples was 23.6%, 20% by using Delvotest® SP NT and Betastar® combo HS kits, respectively. Antibiotic residues could not be detected in heat treated milk. The incidence of Beta lactams and tetracyclines in raw milk samples was 12.7%, 10.1%, respectively by using both Betastar® combo HS kits and HPLC. Quantitative analysis by HPLC revealed that 53.8%, 15.38%, 46.1% and 15.38% from analyzed positive milk samples, the milk samples were contaminated with Ampicillin, Penicillin G, Tetracycline and oxytetracycline, respectively. The mean value of Ampicillin, Penicillin G, Tetracycline and oxytetracycline residues were 902.72± 193.969 µg/L , 9.54± 0.005 µg/L, 1659.3± 685.81 µg/L and 2521.6± 1076.18 µg/L, respectively. Amoxicillin could not be detected in all raw milk samples examined. All positive analyzed samples exceed maximum residue limit which established either by European Union (EU) and Food and Drug Administration (FDA) regulations. The effect of processing on antibiotic residues in milk was studied by application of an experiment. In this experiment, manufacture of white soft cheese was done from spiked raw milk with amoxicillin antibiotic by concentration 4, 40µg/L and oxytetracycline antibiotic by concentration of 100, 1000 µg/L. Milk, curd and whey samples were collected along the processing line of cheese for HPLC analysis. The results of experiment revealed that Pasteurization had a reducing effect on antibiotic residues depending on their heat stability. The antibiotic residues under thermal treatment didn’t totally eliminate. Soft cheese manufacture as a food processing method is not reduce amoxicillin and oxytetracycline residues in milk but, its concentration were highly increase in the curd and whey which increase public health hazards. There are causes that contributed to the increase of antibiotic residues, i.e. binding to milk protein, antibiotic solubility and curdling action of cheese manufacture. Cold storage had a reducing effect on antibiotic residues, total elimination was not occurring. That gives a public health hazard to consumers.