Determination of the limit of detection of penicillin G residues in poultry meat using a low cost microbiological method

Broiler chicken is often grown actively with antibiotics to attain maximum weight within a short period of time. The uncontrolled and unlimited use of these antibiotics may however lead to the accumulation of undesirable residues in the animals treated and their products. In the Kenyan poultry industry there are no inexpensive and easy to perform antibiotic residues screening methods with the capability for a high sample throughput, which can be used to rapidly sift large numbers of samples for suspect or potential non-compliant results. The aim of this study was to determine the limits of detection (LODs) of penicillin G (PEN G) in chicken tissues using a low cost microbiological method. Microbiological detection was achieved by agar well diffusion using Bacillus cereus and Bacillus subtilis. PEN G was detected below the maximum residue limits (MRLs) of 50 ng/g in both liver and kidney with the LODs being 2 times below the MRLs on these plates. It was concluded that both B. cereus plate at pH 7 and B. subtilis plate at pH 7 could be effectively used for routine screening for PEN G residues.