There is growing emphasis on developing biopolymer-based food packaging materials to improve food quality, reduce food waste, and decrease the risk of foodborne diseases. In this study, cinnamaldehyde (CIN), a natural antimicrobial essential oil, was encapsulated within porous vaterite CaCO3 (CA) nanoparticles. The encapsulation efficiency and loading capacity of the cinnamaldehyde in the optimized CA-CIN nanoparticles was 88.9 ± 1.3 % and 9.7 ± 1.4 %, respectively. The release of the essential oil from the CA-CIN nanoparticles was triggered under acidic aqueous conditions, indicating they exhibited water/pH release properties. The minimum inhibitory concentration (MIC) of the CA-CIN nanoparticles against both E. coli and S. aureus was 2 mg/mL. In vitro cell culture studies suggested that the CA-CIN nanoparticles exhibited some cytotoxicity (IC50 = 87 ± 11 μg/mL), indicating that further in vivo toxicity studies are required. A sodium alginate-carboxymethyl cellulose (SC) composite film containing 6 % CA-CIN showed good UV-blocking, water-resistance, and mechanical properties. These films also exhibited good antibacterial activity, extending the shelf life of pork by 2–4 days at 4 ℃. These novel biopolymer-based films may be useful for food preservation applications.