(531b) Synergistic Action of Chitosan Nanoparticles and Low Voltage Electric Field in Bacterial Inhibition

Techniques to inhibit gram-negative bacteria such as shiga-toxin producing Escherichia coli are valuable as the prevalence of large-scale industrial food preparation increases the likelihood of contamination. Chitosan, a deacetylated derivative of chitin, is widely used for drug delivery as a biocompatible, biodegradable polymer with inherent antimicrobial characteristics.  Chitosan inhibits bacteria growth in acidic environments, but is significantly less effective at pH > 7. Pulsed electric fields, constituting another method of bacteria inhibition, are difficult to generate at sufficient strength due to the high electric potentials required. Here, we combine the adsorption of Chitosan nanoparticles  in a very low electric field for an increased inhibition of gram-negative bacteria at mild treatment conditions. Our results show that the synergistic action of these particles with a low voltage electric field applied in two minute time intervals results in significant inhibition of bacteria. Combination of sustained pulses at 100 V/cm and 0.3mg/ml Chitosan reduces the bacteria viability by 2-2.5 orders of magnitude.  In addition, we study the inhibition effect of mixtures containing antimicrobial substances (e.g. nisin, polylysine, or lauric arginate) and Chitosan nanoparticles in the presence of applied electric fields.