الفهرس 
IntroductionOnly 14 pages are availabe for public view
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Abstract
Firstly, to apply, compare and select the most appropriate, valid and accurate method(s) to qualitate and quantitate the antibiotics of tylosin, spiramycin, erythromycin and chloramphenicol residues in fresh buffalo milk, table eggs and chicken meat. Secondly, to use and adopt the selected and appropriated method(s) to determine the mentioned antibiotic residues in foods collected from local markets of great Cairo. The third objective of the current work is to determine the effect of the most common thermal treatments on the previous antibiotic residues in milk, eggs and chicken meat. Methods & Results: Thin layer chromatography-bioautography (TLC-B) was compared with TLC-densitometry (TLC-D) method to determine the three macrolides (tylosin, spiramycin and erythromycin) in foods of animal origin. While, HPLC method was compared with TLC-B method to determine chloramphenicol (CAP) residues in foods of animal origin. The study showed that TLC-B and HPLC methods were proved to be the method of choice to determine the 3 macrolides and chloramphenicol antibiotics, respectively. The recommended methods had the high percentages of recovery and the less detectable amount limits. As well, the recommended methods had capability to determine residues at concentrations markedly lower than the permissible limits of the EU. The percentages of recovery showed lower values 74% ± 4.3 with 5.89% (RSD %), while the higher values reached 91.3% ± 2.0 obtained with RSD percent of 2.92%. Concerning the survey study, 150 random samples from milk, eggs and chicken meat (50 each) were collected from local markets at Great Cairo governorates and submitted for three macrolides and chloramphenicol residues analysis during January to March 2009. The study revealed that buffalo milk exhibited 8 and 24 % of tylosin and chloramphenicol contaminated samples, Table egg samples showed 30, 12, 6 and 6 % contamination levels with tylosin, spiramycin, erythromycin and chloramphenicol, respectively. Chicken meat exhibited that 18 and 6 % of their total samples were contaminated with tylosin and spiramycin residues. The thermo stability of three macrolides and chloramphenicol residues in boiled buffalo milk (5min), chicken eggs (10 min) and chicken meat (30min) based on residue content (1000 µg/kg) for each antibiotic was studied. Data showed that thermal treatment of milk leads to the disappearance of 35, 58, 54 and 12 % from the initial concentration of tylosin, spiramycin, erythromycin and chloramphenicol, respectively. Similarly, the thermal treatments of eggs and chicken meat lead to the disappearance of 34. 61, 35 and 38% (eggs samples) and 63, 83, 65 and 48% (chicken meat samples) of the initial concentration of the 4 successive antibiotics, respectively. Conclusion: The TLC-bioautography (TLC-B) and HPLC methods were the methods of choice for the determination three macrolide and chloramphenicol drugs, respectively after the comparison study. The survey study which carried out during the winter season of 2009 leads to suggest the misuse of the 4 antibiotics to prevent and curate the common diseases of the season. For the thermal stability study, it can be concluded that studied antibiotics were found to be unstable during cooking in the present study.