Submitted to: Calorimetry in Food Processing
Publication Type: Book / Chapter
Publication Acceptance Date: 11/22/2008
Publication Date: 11/2/2009
Citation: Tunick, M.H., Novak, J.S., Bayles, D.O., Lee, J., Kaletunc, G. 2009. Analysis of foodborne bacteria by differential scanning calorimetry. Calorimetry in Food Processing.
Technical Abstract: Heat treatment of food is carried out to inactivate pathogenic and spoilage bacteria and to extend shelf life of products. The processing temperature and time necessary to produce a safe food product are determined using inactivation kinetic parameters for a target microorganism. Because most food processing is associated with heating or cooling of the materials, thermal characterization of foodborne microorganisms will lead to data that can be related directly to the processing protocols. Differential scanning calorimetry (DSC) provides data relevant to heat treatment processes, and can be used for thermal characterization of materials before and after processing. Viability loss and irreversible changes in DSC thermograms of pre-treated whole cells are highly correlated between 55 and 70 deg C. Comparison of DSC scans for isolated ribosomes shows that the thermal stability of ribosomes from E. coli is greater than the thermal stability of L. plantarum ribosomes, consistent with the greater thermal tolerance of E. coli observed from viability loss and DSC scans of whole cells. The calorimetric method provides accurate and reproducible kinetic parameters for inactivation in a shorter time with comparable accuracy to the plate count technique.