Antibacterial and physical effects of cationic starch nanofibers containing carvacrol@casein nanoparticles against Bacillus cereus in soy products.

Bacillus cereus (B. cereus) is a recognized foodborne pathogen widely distributed in various protein-rich foods, which is a huge challenge to food safety. Herein, a novel enzyme-responsive nanomaterial based on cationic starch (CSt) nanofibers loaded with carvacrol@casein nanoparticles (CL@CSNPs) was constructed (CL@CS/CSt nanofiber) to prevent the contamination of B. cereus in soybean products. Considering the excellent antibacterial activity of carvacrol (CL) against B. cereus, CL@CSNPs were prepared by electrostatic adsorption and hydrophobic interaction and characterized by SEM and FTIR.CL@CS/CSt nanofibers with better performance were determined by comparing the physical properties of the electrospinning solution and the prepared nanofiber. Nanofibers were prepared by electrospinning technology and analyzed by SEM and AFM to investigate the size and structural morphology of fibers. FTIR analyses were done to confirm the successful embedding of CL@CSNPs in CSt nanofibers. Subsequently, the controlled release of CL was verified by GC-MS and disc diffusion method. The application experiment results indicated that the treatment based on CL@CS/CSt nanofibers reduced the B. cereus in soy products by 2 log CFU/g, which reflected a significant antibacterial activity. In addition, CL@CS/CSt nanofibers could also prevent texture and chroma changes under refrigeration and maintain the sensory quality of soy products. Thus, CL@CS/CSt nanofibers appear to have great potential in controlling the contamination of soybean products by B. cereus while maintaining the physical quality.