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Title: INHIBITION OF QUORUM SENSING IN CLOSTRIDIUM PERFRINGENS AS A MEANS TOWARD FOOD SAFETY

Author
item Novak, John

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 2/28/2003
Publication Date: 5/14/2003
Citation: NOVAK, J.S. INHIBITION OF QUORUM SENSING IN CLOSTRIDIUM PERFRINGENS AS A MEANS TOWARD FOOD SAFETY. MEETING ABSTRACT. 2003.

Interpretive Summary:

Technical Abstract: Cell density-dependent signaling through the use of autoinducers, classified as quorum sensing, may play a role in the survival and virulence of Clostridium perfringens in foods. The natural 2-(5H)-furanone, ascorbic acid (vitamin C), was chosen for evaluation as a quorum sensing analogue due to its structural similarity to autoinducer-2 (AI-2), a universal signal for inter-species communication. Ascorbic acid has been reported to have antimicrobial properties in meat, and it can be added to meat at concentrations up to 0.75 oz/100 lbs (30 mM). Ascorbic acid inhibition of C. perfringens AI-2 production, growth, sporulation, and enterotoxin (CPE) production was measured following addition to cooked, 93% lean, supermarket ground beef using a Vibrio harveyi luminescence assay. Measured AI-2 production from C. perfringens in ground beef filtrates decreased from 14.6 million relative light units (RLU) at 0 mM ascorbic acid to 8.3 million RLU at 10 mM ascorbic acid to 0.1 million RLU at 30 mM ascorbic acid. To verify that this was not a result of assay inhibition due to the lowering of the pH by ascorbic acid, sodium ascorbate, a non-acidic salt of ascorbic acid, was tested resulting in similar reductions in RLUs despite the absence of pH variations. Total spore production in sporulation medium ranged from 6.83 log spores/ml (0 mM ascorbic acid) to 1.37 log spores/ml (10 mM ascorbic acid). Western immunoblot analyses of SDS-PAGE gels containing cell lysates from C. perfringens indicated highest CPE levels after 24 h at 37C and decreased turn-over of CPE over time in the presence of 10 or 30 mM ascorbic acid. This study demonstrates the potential application of ascorbic acid as a quorum sensing inhibitor for controlling pathogen levels in foods.