); [EMAIL_ADDRESS] (H.C.); [EMAIL_ADDRESS] (H.X.) Xinhua Zhou  
1 School of Chemistry and Chemical Engineering, Zhongkai University of Agriculture and Engineering, Guangzhou 510225, China; LG752492434@126.  
prevent microbial contamination. In practice, chemical anti-bacterial agents are usually added to food directly. Although the bactericidal effect is rapid, the anti-bacterial agent may cause certain carcinogenicity, teratogenicity, and chronic toxicity problems. However, the highly active anti-bacterial agent is attached to the polymer material and packaged into bags [6]. Using fumigation, the agent kills not only bacteria on the food surface, but also microbes in space. To ensure food safety and hygiene, the anti-bacterial agents and polymers do not come into direct contact with food [7; 8]. Therefore, it is important to select a safe anti-bacterial agent and polymer material with good sustained-release properties for the preparation of this anti-bacterial material. Tea tree oil (TTO) [9; 10], a volatile hydrophobic liquid, is produced by the secondary metabolism of plants. It has been shown to be non-toxic, non-irritating, and non-corrosive to humans [11; 12]. On the other hand, TTO exhibits a wide spectrum of anti-bacterial, anti-viral, and anti-inflammatory activities. Its wide range of antimicrobial activity is mainly due to its diversity of components, especially its volatile constituents. The volatile compounds in TTO are mainly 1,8-cineole, terpinen-4-ol, and \(\alpha\)-terpilenol, all of which exhibit antimicrobial activity [13]. 1,8-cineole has been shown to destroy the cell membrane of _E. coli_, while terpinen-4-ol exhibits strong antibacterial, disinfection, and anti-corrosive effects. \(\alpha\)-terpilenol has been demonstrated to feature suitable permeability and exhibits a killing effect on common pathogens such as _Staphylococcus aureus_, _E. coli_, pseudomonas aeruginosa, candida aibicans, etc. [14; 15]. TTO is not harmful to the human body and has a suitable, natural anti-bacterial effect; thus, it may be used as an anti-bacterial agent in food. However, its oxygen-, light-, or temperature-sensitive characteristics greatly affect its overall applicability [16; 17]. [PERSON] et al. [18; 19] have used beta-cyclodextrintrim (\(\beta\)-CD) to capture TTO and form TTO/\(\beta\)-CD aggregates exhibiting high encapsulation efficiency and significantly improved chemical stability of TTO. In addition, TTO/\(\beta\)-CD has been encapsulated into a poly(ethylene oxide) (PEO) matrix by electrostatic spinning. TTO as the active anti-bacterial agent can inhibit the growth of _E. coli_ to prolong the shelf-life of beef. Simultaneously, after coating, the sustained release time of TTO was prolonged significantly at different temperatures (4 \({}^{\circ}\)C, 12 \({}^{\circ}\)C, 25 \({}^{\circ}\)C, and 35 \({}^{\circ}\)C). This may have greatly improved the anti-bacterial effect and application value of TTO. [PERSON] et al. [20] have used sodium alginate (SA) and a quaternary ammonium salt of chitosan (HACC) for the synthesis of TTO-loaded anti-bacterial microcapsules by complex coaervation. These microcapsules were demonstrated to improve the thermal stability and prolong the sustained release time of TTO, ultimately resulting in a sustained anti-bacterial effect against _Staphylococcus aureus_ (_S. aureus_) and _E. coli_. Although the above examples may solve stability and release problems of TTO, the preparation process is rather complex, often involving heating processes that may accelerate the volatilization of the effective components in TTO. However, the preparation of oil absorption microspheres to help adsorb TTO may solve these shortcomings [21]. Polyacrylate crosslinked microspheres represent a new type of oil-absorbing material, as they exhibit powerful oil absorption properties with negligible oil leakage. Furthermore, the structure of the microspheres can be easily adjusted, which may further help regulate the release of volatile oils [22].