Food contamination caused by food-spoilage bacteria and pathogenic bacteria seriously affects public health. Staphylococcus aureus is a typical foodborne pathogen which easily forms biofilm. Once biofilm is formed, it is difficult to remove. The use of nanotechnology for antibiofilm purposes is becoming more widespread because of its ability to increase the bioavailability and biosorption of many drugs. In this work, chitosan nanoparticles (CSNPs) were prepared by the ion–gel method with polyanionic sodium triphosphate (TPP). Cinnamaldehyde (CA) was loaded onto the CSNPs. The particle size, potential, morphology, encapsulation efficiency and in vitro release behavior of cinnamaldehyde–chitosan nanoparticles (CSNP-CAs) were studied, and the activity of CA against S. aureus biofilms was evaluated. The biofilm structure on the silicone surface was investigated by scanning electron microscopy (SEM). Confocal laser scanning microscopy (CLSM) was used to detect live/dead organisms within biofilms. The results showed that CSNP-CAs were dispersed in a circle with an average diameter of 298.1 nm and a zeta potential of +38.73 mV. The encapsulation efficiency of cinnamaldehyde (CA) reached 39.7%. In vitro release studies have shown that CA can be continuously released from the CSNPs. Compared with free drugs, CSNP-CAs have a higher efficacy in removing S. aureus biofilm, and the eradication rate of biofilm can reach 61%. The antibiofilm effects of CSNP-CAs are determined by their antibacterial properties. The minimum inhibitory concentration (MIC) of CA is 1.25 mg/mL; at this concentration the bacterial cell wall ruptures and the permeability of the cell membrane increases, which leads to leakage of the contents. At the same time, we verified that the MIC of CSNP-CAs is 2.5 mg/mL (drug concentration). The synergy between CA and CSNPs demonstrates the combinatorial application of a composite as an efficient novel therapeutic agent against antibiofilm. We can apply it in food preservation and other contexts, providing new ideas for food preservation.

Prebiotics can stimulate the growth and activity of probiotics and have a variety of physiological functions. However, the study of walnut oligopeptides as prebiotics to promote probiotics is rarely reported. Therefore, in order to explore the beneficial effect of walnut oligopeptide (WOPs) on Lactobacillus plantarum Z7, WOPs was added to the medium of L. plantarum Z7, and the utilization of WOPs, the effect of WOPs on the biofilm, extracellular polymeric substances, and bacterial death were explored. The results showed that the growth‐promoting effect was strengthened with the increasing concentrations of WOPs. The content of bacterial biofilm and EPS increased significantly, and the number of dead bacteria decreased. The beneficial effect of WOPs was probably because that it enhanced the secretion of biofilm which was regulated by bacterial quorum sensing system and promoted the ability of bacteria to resist the adverse environment, thus promoting the growth and reproduction of bacteria.