Bioderived Poly(lactic acid) Composite with Chitosan: Physical Properties and Antimicrobial Effect in Combination with Mild Heat and UV-A Light

An antimicrobial and biodegradable composite was prepared by melt-blending poly(lactic acid), polyhydroxybutyric acid, and chitosan and then challenged against Escherichia coli K12 and Listeria innocua in apple juice in combination with either UV-A light irradiation or mild heat (50 °C). The composite (PLA-CHI) combined with UV-A light irradiation reduced the populations of E. coli K12 and L. innocua by 99.8% and >99.998%, respectively. PLA-CHI combined with mild heat (50 °C) reduced the populations of E. coli K12 and L. innocua by 99.9% and >99.998%, respectively. Surface analysis confirmed the overall chemical stability of PLA-CHI. Compared to poly(lactic acid), values of the thermal properties decreased, water vapor permeability was unchanged, oxygen permeability increased, and mechanical properties remained stable. These results suggest that integrating biodegradable and antimicrobial materials with UV-A irradiation or mild heat represents an effective hurdle technology for food preservation.