Submitted to: Journal of Thermal Analysis
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: August 10, 2005
Publication Date: January 6, 2006
Citation: Tunick, M.H., Bayles, D.O., Novak, J.S. 2006. Thermal analysis of ribosomal proteins in foodborne bacteria. Journal of Thermal Analysis. V. 83; No.1. Interpretive Summary: Over four million Americans are sickened each year by dangerous varieties of bacteria in their food. Many of these illnesses are caused by two bacteria, Clostridium perfringens and Listeria monocytogenes, both of which are killed by sudden heating or cooling. Experiments were conducted using differential scanning calorimetry (DSC), a technique that measures the effect of temperature on a sample, to determine how temperature changes could be used to make food safe from these organisms. Our results showed that the ribosomes, the parts of the cell that make protein, are damaged by refrigeration and heating. This temperature treatment affects proteins in ribosomes in much the same way that antibiotics work. Food processors will be able to use heat and cold to stop the growth of Clostridium perfringens and Listeria monocytogenes, making our food supply safer.
Technical Abstract: Differential scanning calorimetry (DSC), which is often used to measure the thermal profiles of lipids, carbohydrates, and proteins in food, is also applicable to studying the thermal properties of bacteria. Foodborne pathogens are inactivated by heat, and denaturation transitions observed by DSC indicate potential sites of cellular injury. Ribosomes, which are the sites for messenger RNA translation, are one critical component of thermal damage as evidenced by characteristic denaturation transitions in the 66-74°C range. These transitions are affected when cells of Clostridium perfringens and Listeria monocytogenes are cold-shocked by refrigeration, subjected to heat, or exposed to antibiotics. The data suggest that food processors could control pathogens by manipulating refrigeration and/or heat treatment to impair ribosomal function.