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Disease and food spoilage-causing microorganisms can adhere to food contact surfaces and become much more resistant to sanitizers then when they are not adhered. The adhered bacteria together with entrapped organic matter form what is called a biofilm which can protect bacteria from the action of antimicrobials. A novel approach to controlling adhered bacteria and formation of biofilms is to inhibit the initial adhesion of microbial contaminants by application of an antimicrobial agent to food contact surfaces as opposed to trying to remove them once they are adhered. Our hypothesis has been that if both the presence of an antimicrobial and its activity are maintained at the food contact surface, sensitive bacterial cells or spores that attempt to adhere would be killed.
We have already demonstrated the validity of the hypothesis by observing that the protein antimicrobial nisin can adsorb to surfaces, maintain activity and kill cells that have adhered. In this study, we will extend our work by using a second antimicrobial protein; hen egg-white lysozyme. This agent has an enzymatic mode of inhibition which is different from that nisin which has a detergent like lytic activity. We will address two major questions. One is fundamental and relates to determination of molecular influences on the enzymatic activity of lysozyme on surfaces. The other question relates to evaluation of the antimicrobial activity of hen lysozyme at surfaces, and synergistic/antagonistic effects gained by the action of lysozyme and nisin in tandem.