Photodynamic inactivation of Burkholderia cepacia by curcumin in combination with EDTA.

Burkholderia cepacia (B. cepacia) is an aerobic Gram-negative bacillus found in various aquatic environments and can cause food contamination. We investigated the photodynamic antibacterial effects of food additive curcumin combined with EDTA on B. cepacia. We found a ~4-log reduction in B. cepacia viability when photo-irradiated with curcumin at 50 μM by blue LED light (16 mW/cm2) for 30 min with 0.4% (w/v) EDTA. Moreover, the bacterial morphological alterations and the leakage of intracellular contents were observed after photodynamic treatment. There were also obvious genomic DNA cleavage and a general loss of bacterial proteins assigned to large-scale protein degradation after photodynamic inactivation treatment. Collectively, curcumin in combination with EDTA illuminated by blue LED is a potential candidate for photodynamic inactivation of B. cepacia.