Processed cheese faces challenges related to short shelf life and susceptibility to microbial contamination during room temperature storage. Nisin, a natural antimicrobial peptide used for food preservation, exhibits limited sustained activity and a narrow antimicrobial spectrum, making its enhancement essential. To address these issues, this study employed electrostatic self-assembly technology to develop chitosan-pectin nanoparticles loaded with nisin (CNP) to improve processed cheese stability at room temperature. The CNPs formed through electrostatic interactions and hydrogen bonding, exhibited ellipsoidal or polyhedral shapes. The encapsulation efficiency and loading capacity of CNPs were 73.93 % and 34.48 %. The CNPs provided sustained nisin release, significantly inhibiting the growth of Gram-negative bacteria such as Escherichia coli and Salmonella enterica . Notably, the addition of CNP, extended the shelf life of processed cheese by at least 21 days at room temperature, maintaining product stability. This study presents an innovative and efficient solution for processed cheese preservation at room temperature.
In the present study, we developed a nanozyme-based direct competitive immunoassay to detect walnut allergen (Jug r 4) in foods. Walnut monoclonal antibody (mAb) and Cu 2− x Se@Bi 2 MoO 6 nanocomposites were generated to form a signal probe by electrostatic adsorption. The nanocomposites had high peroxidase-like activity and could be stored at room temperature. The linear range of the optimized assay was 137.35 ± 0.14 to 3526.0 ± 4.53 μg/L with a limit of detection of 81.63 ± 0.89 μg/L. This method was validated by detecting walnut protein in bread, biscuits, and milk samples, providing recovery rates of 70.63–127.04 %. The fast and sensitive assay was suitable for the rapid detection of walnut allergen in foods.
危险品化学品经营许可证（带存储）