PPT-Controlling Microbial Growth in the Environment

9 Figure 91 A plot of microbial death rate Constant percentage of the extant population is killed each minute Basic Principles of Microbial Control Action of Antimicrobial Agents Alteration of cell walls and membranes. in vitro. CLS 212: Medical Microbiology. . Microbicidal. or . Microbistatic. ?. . Microbicidal. . Microbicidal. . is . the process . or . an agent . that . kills. the microorganism. . Microbial food spoilage occurs as a consequence of either microbial growth in a food or release of extracellular and intracellular(following cell . lysis. ) . enzymes in the food environment.. Signs of spoilage of different types of food:. Eric J. Raes, P.E. ., LSRP. Engineering and Land Planning . Dora Ogles, Brett Baldwin, Kate Clark & . Anita Biernacki. Microbial Insights Inc.. Kerry Sublette, Ph.D., Kate Key. University of Tulsa. THE ORIGIN AND EVOLUTION OF MICROBIAL LIFE. HOW DID LIFE ORIGINATE?. SPONTANEOUS GENERATION. LIFE ARISING FROM NON-LIVING MATTER. LONG BELIEVED AS THE ACCEPTED EXPLANATION OF ORIGINATION OF LIFE. EXPERIMENTS EVENTUALLY SHOWED IT TO BE IMPOSSIBLE. A. Metabolism. 1. Anabolism. A) synthesis reactions (building up). 2. Catabolism. A) lysis reactions (breaking down). B. Enzymes. 1. proteins that facilitate chemical reactions. Microbial Metabolism. A. Microbial Reproduction. 1. binary (transverse) fission. A) parent cell enlarges and duplicates all its genetic material. B) DNA copies move to opposite ends of parent and attach to a section of the cell membrane as it begins to pinch together at the center. A. Structure of DNA. 1. discovered by James Watson and Francis Crick in 1953. 2. stores genetic information for the production of proteins. 3. composed of nucleotides. A) a nucleotide is composed of a nitrogenous base, sugar, and phosphate. . Definitions. Indigenous . flora. microorganisms . native or belonging naturally to a region.. Colonization. establishment . of a site of reproduction of microbes on a person without necessarily resulting in tissue invasion or . In the Environment. Table 9.1 Terminology of Microbial Control. Figure 9.1 A plot of microbial death rate.. Basic Principles of Microbial Control. Action of Antimicrobial Agents. Alteration of cell walls and membranes. Microbiology. Microbial Growth. Microbial requirements for growth:. 1. . Physical. A. . Temperature. Optimal growth temperature. Permissible range. human pathogens optimal = . 37°C. Microbial Growth. Microbial growth is the increase in number of cells, not cell size. Microbial Growth. The Requirements for Growth: . Physical Requirements. Temperature. Minimum growth temperature. Optimum growth temperature. (a) Intrinsic factors: . These. . are inherent in the food. They include:. pH,. . water activity,. . oxidation reduction potential,. . nutrient content,. . antimicrobial contents,. . biological structure. Musafer. PhD. Microbial growth defined as an increase in cellular constituents resulting an increase in a microorganism size, population number or both.. 1-Lag phase. When M.O are inoculated into fresh culture medium, will not reproduce immediately, therefore this period is called the lag phase. . Growth: . A. n . increase in cell number, not in cell size. .. Bacteria . grow and divide by binary fission, a rapid and relatively simple process. .. Phases . of Growth Bacterial Growth Curve : . When .