Department of Biochemistry and Molecular Biology, Kenya; Department of Dairy and Food Science and Technology, Egerton University, PO Box 536, Egerton, Kenya
Mwangi, W.W., Department of Biochemistry and Molecular Biology, Kenya; Shitandi, A., Department of Dairy and Food Science and Technology, Egerton University, PO Box 536, Egerton, Kenya; Ngure, R., Department of Biochemistry and Molecular Biology, Kenya
In the Kenyan poultry industry, there is lack of affordable and easy-to-perform antibiotic residue screening methods. The aim of this study was to determine the limits of detection (LODs) of oxytetracycline (OTC) and evaluate whether it is reliably detectable at maximum residue limits (MRLs) in poultry tissues. Microbiological detection was achieved by agar well diffusion using Bacillus cereus, three medium pH and two poultry organs. Inhibition zones increased significantly (P<0.001) when OTC was detected at a decreasing pH in both the liver and the kidney. OTC was detected below the MRLs of 600ng/g in the liver and 1,200ng/g in the kidney. However, growth media pH and antibiotic concentration affected the LODs. B. cereus plate at pH 7 can be used effectively for routine screening for OTC residues. The LODs were 131.3ng/mL and 33.4ng/mL, in the liver and the kidney, respectively. © 2011 Wiley Periodicals, Inc.