1 0 obj environment; the examples of sufate reducing and diazotrophic bacteria thriving in the root rhzosphere are a good illustrations of such natural gradients. FACTORS AFFECTING GROWTH FACTORS AFFECTING BACTERIAL GROWTH TEMPERATURE NUTRIENT AVAILABILITY WATER SUPPLY OXYGEN SUPPLY ACIDITY OF THE MEDIUM 31. Intrinsic Factors ... Is one of the most importatnt environmental factors , controlling the rate of cell division (multiplication) of microorganisms • We recognize 3 basic temperatures Solutes and Water Acidity 2. Yet, the majority of microbes are neutrophiles preferring environmental pH levels of 5.5-8.0. Pathogenicity is the ability of a microorganism to cause disease in another organism, namely the host. Intrinsic Factors • Nutrients • pH and buffering capacity • Redox potential • Water activity • Antimicrobial constituents • Antimicrobial structures . This preview shows page 1 - 2 out of 7 pages. ",#(7),01444'9=82. Depending on the Optimum pH for Growth 4. The kinetics of microbial growth are covered in the third part of the chapter. The growth of microbial cells is affected by different environmental conditions (both physical and chemical) such as pH, temperature, salinity, gas concentration (O 2, CO 2, and H 2 ), water activity and osmosis. %PDF-1.5 endstream Control of Microbial Growth: Rate of Microbial Death When bacterial populations are heated or treated antimicrobialchemicals, they usually die at a constant rate. Weight for weight, these food components will decrease aw in the following order: ionic, compounds > sugars, polyhydric alcohols, amino acids and other low-molecular-weight. 2. Hence factors such as osmotic pressure and salt concentration of the solution affect the growth of bacteria. <> Your plan should be to prevent bacteria from entering into the growth phase. FACTOR AFFECTING MICROBIAL GROWTH IN FOOD BY, HANU PRATAP 1 2. responding to the loss or gain in water associated with changes in osmolarity of the environment. Factors Affecting Microbial Growth Food. 2. Some require high moisture. Gram-negative bacteria such as. The control of the, moisture content in foods is one of the oldest exploited preservation strategies. Temperature: most important B. Osmotic conditions (levels of salt or other solutes dissolved in water) C. pH D. Nutrient/chemical availability 1. elements 2. trace elements 3. organic additives E. Oxygen: second most important. Bacteria grow only in the absence of oxygen, called: strict anaerobe. Temperature requirement. <> po = vapor pressure of the solvent (usually water). endobj The controlled flow of, water by a bacterial cell is important to ensure survival. The aw of a food describes the degree to which water is "bound" in the food, its availability to, participate in chemical/biochemical reactions, and its availability to facilitate growth of, microorganisms. Growth Curve. Factors affecting microbial growth in food • Intrinsic Factors • Environmental Factors • Implicit Factors • Processing Factors . Inhibition of Microbial Growth. Environmental Factors Environmental factors which affect plant growth can be classified as abiotic factors and biotic factors. stream Different Seasons. Summarize the strategies used by nonextremophiles to acclimate to changes in their environment 4. Microbial Growth FATTOM Food Acid Temperature Time Oxygen Moisture Factors Affecting Microbial Growth. Bacterial cell surfaces may be damaged by the acceleration forces attained in centrifuges. These include natural food compounds, preservatives, the oxidation-reduction potential, aw, and pH. Those factors inherent to, These include natural food compounds, preservatives, the oxidation-, Microorganisms need water in an available form to grow in food products. A producer has control over the genetic factor by his choice of variety. The aw of a food, on this scale from 0.00 - 1.00 is related to the equilibrium relative humidity above the food on a. scale of 0 - 100%. The use of multiple environmental factors (i.e., pH, salt concentration, tem- perature, etc.) Environmental factors that affect plant growth include light, temperature, water, humidity, and nutrition. The factors are: 1. Note that: • The effect of temperature on microbial growth also depends upon other environmental conditions such as: o Growth factors in the nutrient medium, opH of the food, and oWater activity. Factors affecting bacterial growth Factors affecting bacterial growth are: 1. Bacteria must be capable of rapidly. Microbial Growth FATTOM Food Acid Temperature Time Oxygen Moisture Factors Affecting Microbial Growth. Supply of Nutrient Elements 9. Some like it hot while others like it cold. Soil Organic Matter: The dead organic material of plant and animal origin serve as total soil organic … Depending on the Requirement of Oxygen/Air for Growth 2. ADVERTISEMENTS: Some of the environmental factors influencing growth of bacteria are: 1. B. Factors affecting microbial growth.pdf, Safe_Practices_for_Food_Processes_Chpt._3_Factors_that_Influence_Microbial_Growth, California Polytechnic State University, San Luis Obispo • ASCI 211, Universiti Putra Malaysia • FOOD TECHN 37, FST 50 Lecture 2 - Microorganism & Food Spoilage.pdf. Introduction Intrinsic and extrinsic factors are both important to microbial growth. Some of the important factors affecting bacterial growth are: Nutrition concentration 2 0 obj Many require the presence of oxygen, but some do not. Temperature Theoretically, bacteria can grow at all temperatures between the freezing point of water and the temperature at which protein or protoplasm coagulates. Extrinsic factors are those that refer to the environment surrounding the food such as temperature. Summarize the adaptations of extremophiles to their natural habitats 3. Oxygen requirement. Title: Factors affecting microbial growth 1 Factors affecting microbial growth 2 Factors affecting microbial growth. The major groups have been categorized in food-spoiling, intoxicating, and disease-causing bacteria with their specificity at various temperature, pH, air, O 2 requirement along with the antimicrobial compounds present in the food. 3. Food. Environmental and Physiological Factors Affecting High-Throughput Measurements of Bacterial Growth Esha Atolia,a Spencer Cesar,b Heidi A. Arjes, cManohary Rajendram, Handuo Shi,b,c Benjamin D. Knapp,d Somya Khare,c Andrés Aranda-Díaz,c Richard E. Lenski,e,f Kerwyn Casey Huangb,c,d,g Absence of Growth Inhibiting Substances. glucose) for building blocks. Course Hero is not sponsored or endorsed by any college or university. Osmotic pressure (salt tolerance). Hurdle technology is becoming an increasingly popular preservation strategy. pH measures how acidic or basic (alkaline) a solution is, and microbes may grow in either acidic, basic, or neutral pH conditions. Introducing Textbook Solutions. Enteric Bacteria survival in aquatic environment is impacted to a great extent by the ability of bacterial cells to survive in adverse environmental conditions. Factor # 1. (Sections 5.1,5.4) Since environmental factors, such as light, temperature, vary widely in time, it is not. Sofos, in Encyclopedia of Food Safety, 2014. compounds > high-molecular-weight compounds such as cellulose, protein or starch. Pathogens vary in their ability to produce disease. Soil Moisture 2. 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