QUORUM QUENCHING ACTIVITY OF SELECTED ORGANIC ACIDS AGAINST FOOD SPOILAGE BACTERIA PSEUDOMONAS AERUGINOSA PUFSTB04

Biofilms cause profound impact on the safety and quality food products and contaminate the product through the introduction of pathogenic microorganisms or spoilage bacteria. Quorum sensing (QS) is a type of bacterial communication system that relies on secreted signaling molecules which regulate coordinated responses across a bacterial population such as biofilm formation. It has been theorized that, if the signal communication was blocked, bacteria would lose their ability to mount an organized assault on the host and thus their ability to form organized community structures would be compromised. In the present work organic acids namely acetic acid, citric acid and lactic acid are evaluated as potential quorum sensing inhibitor (QSI) often referred as Quorum quenching. Inhibition of various QS regulated phenotype was assessed using indicator microorganism Chromobacterium violaceum CV02656 (violacein production) and Pseudomonas aeruginosa PUFSTb04 (EPS production, biofilm formation, virulence etc.,). These organic acids inhibited the growth of CV02656 eventually inhibiting the violacein production. Organic acids specifically inhibited the violacein production in C. violaceum maximum upto 45.4%.he effect of organic acids on QS based phenotypes was studied using P. aeruginosa (PUFSTb04) a spoilage bacteria which shows by quorum sensing pathway. The effect of organic acids to interrupt the QS regulated phenotypes was also assessed, and it was found to reduce the EPS production, biofilm formation and virulence ability of P. aeruginosa in a concentration dependent manner. The inhibition of biofilm formation was high for citric acid and acetic acid with 69.39% and 66.12% respectively at a concentration of 2 mg/ml. The inhibition of pyoverdin production of P. aeruginosa seems to be 75.11%, 73.46%, 83.05% respectively with the organic acids. The study reveals that these organic acids can be used as anti-quorum agents and can decreasespoilage in foods.