Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: February 7, 2005
Publication Date: June 14, 2005
Citation: Tunick, M.H., Bayles, D.O., Novak, J.S. 2005. Analysis of foodborne bacteria by differential scanning calorimetry. (abstract). IFT Annual Mtg. Paper No. 74-2. Available: http://ift.confex.com/ift2005/techprogram/paper 27433 htm. Technical Abstract: Foodborne pathogens are responsible for more than four million illnesses and 1300 deaths in the U.S. annually. Methods for inactivating these microorganisms must be developed to insure the safety of the food supply. Differential scanning calorimetry (DSC), which is often used to obtain thermal profiles of lipids, carbohydrates, and proteins in food, was applied to the study of the thermal stability of two types of foodborne bacteria, Clostridium perfringens and Listeria monocytogenes. Pathogens are inactivated by pasteurization or refrigeration, and thermal transitions of ribosomes, as monitored 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 disappear or shift to different temperatures when cells of C. perfringens and L. monocytogenes have been treated with heat or cold. The results suggest that protein synthesis in pathogens is altered by changes in ribosome proteins. Temperature treatment of food inactivates pathogens, and DSC shows the mechanism for this inactivation.