Foods may contain multiple microenvironments. sterilant. 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. When microorganisms grow in food, they cause varying degrees of change in the characteristics of the food. Specific growth factors may also be required such as blood or specific type of protein. Factor # 1. Physical factors- Temperature, pH, osmotic pressure, hydrostatic pressure and radiation. The optimum growth pH is the most favorable pH for the growth of an organism. milk, meat, they do not show pH reduction. The lowest pH value that an organism can tolerate is called the minimum growth pH and the highest pH is the maximum growth pH.These values can cover a wide range, which is important for the preservation of food and to microorganisms’ survival in the stomach. Intrinsic factors are those that are characteristic of the food itself; extrinsic factors are those that refer to the environment surrounding the food. The pH of a food affects microbial growth and viability. Most fresh foods, such as fresh meat, vegetables, and fruits, have a. w values that are close to the optimum growth level of most. This is well illustrated by the food poisoning outbreaks in aerobic foods caused by the strict anaerobe Clostridium botulinum. LECTURE 3 INTRINSIC AND EXTRINSIC FACTORS AFFECTING THE TYPE AND NUMBER OF MICROORGANISMS IN FOODS 2. ability to participate in chemical/biochemical reactions, and its. Intrinsic factors include those that are internal to the food product itself, such as nutrient content, pH levels, water activity, redox potential, and other antimicrobial components acting as defense mechanisms against microbes. PK ! �U ����^�s������1xRp����b�D#rʃ�Y���Nʬr��ɗJ�C.a�eD��=�U]���S����ik�@��X6�G[:b4�(uH����%��-���+0A?�t>vT��������9�. Moreover, taking medicines can result in depression that can alter your food pattern. Microbial growth is the most important factor because it affects the safety of the product. Although bacteria do increase in size before cell division, bacterial growth refers to an increase in the number of organisms rather than an increase in their size. Influence. Factors Affecting Microbial Growth The key to a productive staff is creating and maintaining a safe and healthy work environment. Inhibition of Microbial Growth. around 0.98-1). Growth rate is greater when all conditions are optimized and any alteration on these conditions will reflect on the growth rate (figure 2). Bacteria - Bacteria - Growth of bacterial populations: Growth of bacterial cultures is defined as an increase in the number of bacteria in a population rather than in the size of individual cells. Two factors heavily influence the level of cleanliness required for a ... and food industry settings, where it may be imperative for certain items to be completely free of potentially infectious agents. psychrophiles Influence of environmental factors on microorganisms. To finish the main factors that affect bacterial growth are resource availability, metabolism, temperature, pH, … Growth of bacteria is affected by many factors such as nutrition concentration and other environmental factors. Often, the results of such interplay are unpredictable, as poorly understood synergism or antagonism may occur. Nutrients that vary greatly with type of food example are meat is rich in proteins, lipids, minerals, and vitamins but poor in carbohydrates. Extrinsic Factors: 1. It is important to store, prepare and cook foods safely in order to reduce the risk of bacteria multiplying and causing foodborne illness. ... handling practices and gloves changing are critical steps that influence microbial transfer to foods. Many factors must be evaluated for each specific food when making decisions on whether it needs time/temperature control for safety. Water activity is defined as the ratio of water vapor pressure of the food substrate to the vapor pressure of pure water at the same temperature (Jay 2000b, p 41): For questions about accessibility and/or if you need additional accommodations for a specific document, please send an email to ANR Communications & Marketing at anrcommunications@anr.msu.edu. Factors that Influence Microbial Growth ... system to address foods that may require time/temperature control for safety reasons. Science Advisory Board. The following economic factors may affect food product development: �� PK ! Roy G. 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