Cassava starch films incorporated with nisin and cardamom essential oil for controlling foodborne pathogens

Biodegradable films with natural antimicrobials are a promising approach to improve food safety. In this study, cassava starch films were prepared with cardamom essential oil (CEO, 5% v/v) and nisin (0.1–1.0%, w/v), and their structural, physicochemical, migration, biodegradation, and antimicrobial properties were evaluated. The addition of CEO and nisin maintained film integrity, although slight microstructural changes were observed at higher nisin concentrations (0.5–1.0%). Swelling increased with nisin content, from lower values in control and 0.1% formulations to higher values at 1.0%, indicating greater water uptake. Thermal analysis showed that all films retained the typical multi-step degradation profile of starch without significant shifts in thermal behavior. Migration studies indicated a gradual and temperature-dependent diffusion of both compounds. All films degraded over 60 days, confirming their environmental compatibility. CEO alone showed bacteriostatic effects, while films containing CEO and nisin achieved reductions greater than 3 log CFU/mL against Salmonella gallinarum, Staphylococcus aureus , and Listeria monocytogenes . Overall, the combined use of CEO and nisin improved antimicrobial performance without compromising film stability or biodegradability, supporting their application in active food packaging.