Hollow calcium carbonate microspheres prepared from waste eggshells as pH-responsive controlled-release carvacrol for efficient and safe antimicrobial agents in pork preservation

The application of safe controlled-release antimicrobial agents can significantly enhance the storage and preservation of meat, providing substantial commercial value. This study utilized waste eggshells to prepare CaCO₃ hollow microspheres loaded with carvacrol (CA) to enhance the bactericidal effect of carvacrol (microSCaCA), forming a pH-responsive controlled-release antimicrobial agent. The release performance and antimicrobial effects were investigated, and after ensuring cellular non-toxicity, the preservative effects on refrigerated pork were examined. Results showed that the CaCO₃ hollow microspheres could load up to 86.20 mg/g of CA, with improved release performance at lower pH values. In a PBS solution at pH 5.0, the cumulative release rate of carvacrol reached 65.73 % within 60 h, approximately 4.65 times higher than in neutral pH conditions. MicroSCaCA significantly inhibited E. coli and S. aureus and demonstrated good biosafety in cytotoxicity tests. When applied to the preservation of pork at 4 °C, microSCaCA significantly improved preservation indicators and extended the shelf life of fresh meat by 4 days. This study not only enhanced the application effectiveness of carvacrol through waste utilization but also provided a new pathway for the antimicrobial use of plant essential oils, demonstrating the potential application value of CaCO₃ hollow microspheres in antimicrobial and food preservation applications.