Lanthanum oxide-loaded bacterial cellulose film with antibacterial and antioxidant properties exhibiting real-time pH response for smart food preservation packaging.

Inadequate food preservation has become a serious public health and environmental challenge. Foodborne illnesses caused by microbial contamination, chemical spoilage, and improper storage pose serious threats to human health and place additional pressure on the sustainability of the food supply chain. To address environmental pollution and food spoilage, it is essential to develop multi-functional intelligent food packaging materials. Herein, a novel multifunctional bio-composite film (BC-La2O3/Cur/CD) was fabricated by incorporating curcumin-β-cyclodextrin inclusion complex (Cur-β-CD) and lanthanum oxide (La2O3) into a bacterial cellulose (BC) matrix for intelligent food packaging. Compared with pure BC, the composite film exhibits integrated antimicrobial, antioxidant, barrier, and mechanical properties. Specifically, the composite film achieved 100% inhibition rates against both E. coli and S. aureus, and showed DPPH and ABTS radical scavenging rates of 76% and 97%, respectively. Consequently, the film effectively inhibited spoilage microorganisms and extended the shelf life of basa fish. Moreover, its color changed in response to alkaline volatile amines accumulated during storage, offering visual freshness monitoring. Biocompatibility tests confirmed that the film did not increase plant or cell mortality, supporting its safety as an active food packaging material. This work offers a viable strategy for the design of rare earth-containing bio-composite films with integrated antioxidant, antibacterial and intelligent freshness-monitoring functions.