Decomposition of antibiotics by gamma irradiation: Kinetics, antimicrobial activity, and real application in food matrices

Veterinary antibiotics are widely used to treat and prevent diseases and are also incorporated into animal feed to improve growth rate and production efficiency. There is growing concern regarding the potential impact of antibiotic residues on the environment and human health by leading to increased antibiotic resistance of microorganisms and negative influence on human by triggering allergic reactions. In this study, we investigated the destruction of commonly used veterinary antibiotics in water and various food commodities by ionizing gamma irradiation. We began by thoroughly investigating the decomposition of Amoxicillin, Doxycycline, and Ciprofloxacin in water at an initial concentration of 50 mu M. All investigated compounds follow pseudo-first-order kinetics and the removal reached at least 90% at an absorbed dose of 7 kGy. This absorbed dose was applied to study the antimicrobial activity of the resulting decomposition solutions, by performing E. coli antimicrobial experiments. The application of 7 kGy resulted in a complete removal of the activity of the target antibiotics. In fact, H-1 NMR and TOC experiments indicated that a complete mineralization of the target antibiotics is achieved at 7 kGy. The investigation was extended to evaluate the effectiveness of gamma irradiation in removing antibiotics from more complex matrices such as milk, chicken meat, and eggs. Overall, comparable antibiotic removal percentages were achieved in the studied food samples compared to those in water samples. Our study provides a practical solution to the growing concern of the presence of antibiotic residues in water and food. Well-established ionizing radiation technologies, such as high-energy electron beam, can be applied to remove antibiotic residues from bulk food products as well as water bodies.