Submitted to: International Journal of Food Microbiology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: November 11, 2003
Publication Date: December 1, 2003
Citation: Medina, M.B. 2004. Binding interactions of extracelluar membrane and muscle proteins with immobilized salmonella typhimurium using an spr biosensor. International Journal of Food Microbiology. 93. p. 63-72. Interpretive Summary: Most foodborne diseases are caused by consumption of foods contaminated with human pathogenic bacteria. In a 1996 active surveillance of the seven food-borne diseases that were culture confined, Salmonella had the second highest incidence at 16 per 100,000 population and the highest death rate of 47% (16 of 34). The incidence of Salmonella in raw poultry is 10-12%. Therefore, any new approaches to reducing or eliminating pathogen contamination in foods would decrease foodborne illness and medical costs and provide savings to the food industry. Poultry can be contaminated with fecal matter, wash water or contact with contaminated surfaces. Contamination is controlled by washing with sanitizers and by preventing recontamination of the carcasses after sanitizing. We study the mechanisms of how bacteria attach to poultry carcasses, and we are also evaluating food grade chemicals that will block bacterial attachment to the outer surfaces of chickens. We used a biosensor instrument to study the binding of collagen and other proteins from chicken skin and fascia (connective tissue beneath the skin) to Salmonella which had been chemically fixed on a biosensor. We evaluated food grade carrageenans and other additives to determine the ability to block collagen binding to Salmonella. The carrageenans demonstrated that greater than 90% of the purified collagen was blocked from binding to the Salmonella. These compounds are also being tested on chickens. These biosensor studies provide a rapid assessment of potential blocking agents that can be used to treat poultry after sanitizing such that recontamination can be minimized.
Technical Abstract: Most foodborne diseases are caused by consumption of foods contaminated with human pathogenic bacteria. Our research attempts to reduce bacterial contamination in poultry. Real-time interactions of extracellular membrane proteins (collagen I, fibronectin, laminin) and muscle proteins (actin and myosin) with immobilized Salmonella typhimurium were studied. Salmonella typhimurium cells were immobilized on the sensor chip of a surface plasmon resonance biosensor (BIAcore). Results showed that collagen I and laminin bound to the S. typhymurium surface but fibronectin and myosin had lower binding while actin had no detectable interaction. The binding kinetics of collagen I and Salmonella cell surface showed an apparent dissociation and association rate constants of 3.90E-4 per sec and 1.07E+4 per mole per sec in 12 replicate analyses. A model system was further developed to evaluate the interactions of carrageenans and other polysaccharides utilizing collagen binding to the Salmonella sensor surface. In a 2:1 ratio of collagen to polysaccharides, kappa-carrageenans inhibited 92 - 100% of collagen binding to the Salmonella surface while sodium alginate and low methoxy pectin had 50 and 18% inhibition, respectively. These biosensor studies allowed us to rapidly evaluate compounds that may be used to prevent bacterial attachment to poultry skins and carcasses. Such compounds can be used in new intervention techniques to reduce pathogen contamination in poultry.