Valorization of the chicken by-product waste with supercritical CO₂ inactivation of microbes towards sustainable utilization

There is an increasing concern on the presence of antibiotic-resistant bacteria in the environment. The existing practice of chicken by-product waste is to dispose in a landfill. Chicken by-product waste may contain antibiotic-resistant bacteria. Thus, the disposal of chicken by-product waste into the landfill leads to the release of antibiotic-resistant bacteria into the environment. In the present study, the supercritical CO₂ (scCO₂) technology was utilized to sterilize the chicken by-product waste to ensure safe handling for the subsequent processing towards sustainable utilization of the waste by-product. In addition, the presence of bacteria in the chicken by-product waste and their antibiotic susceptibility were identified. The influence of the scCO₂ sterilization on the inactivation of the antibiotic-resistant bacteria in chicken by-product waste was determined with varying pressure (8–40 MPa), temperature (30–80 °C), and treatment time (15–90 min). The experimental conditions of the scCO₂ sterilization were optimized based on the maximum log reduction (logCFU/g) of bacteria in sterilized chicken by-product waste. The optimum experimental conditions for the complete inactivation of the antibiotic-resistant bacteria in sterilized chicken by-product waste were scCO₂ pressure 18 MPa, temperature 60 °C, and treatment time 45 min. The sterilized chicken by-product waste contains about 50% fat. The findings of the present study would be useful to determine the sustainable utilization of chicken by-product waste with minimizing human health hazards and environmental pollution. Graphical abstract: [Figure not available: see fulltext.]