2. Growth factors are organic compounds such as amino acids , purines , pyrimidines , and vitamins that a cell must have for growth but cannot synthesize itself. f. Growth factors. The factors affecting microbial survival and growth in foods determine the nature of spoilage and any health risks. 4 0 obj Factors affecting bacterial pathogenicity. �5k��"�MiSV��Pm�*i����=�u��o� 3 0 obj <> endobj Factors can be divided into four groups: physicochemical properties of the food, conditions of the storage environment, interactions of microorganisms, and process factors such as physical treatments and addition of chemicals. glucose) for building blocks. endobj <>/XObject<>/ProcSet[/PDF/Text/ImageB/ImageC/ImageI] >>/MediaBox[ 0 0 540 720] /Contents 4 0 R/Group<>/Tabs/S/StructParents 0>> endobj High temperatures damage microbes by denaturing enzymes, transport carriers, and other proteins. ",#(7),01444'9=82. Factors affecting bacterial growth are: 1. <> <> Hence factors such as osmotic pressure and salt concentration of the solution affect the growth of bacteria. Effect of water availability 9. Compounds affecting microbial enzymes (oxidative agents, chelating agents, heavy metals, antimetabolites) Compounds reacting with DNA ( chemical mutagenes – alkylating or deaminating agents, cytostatics) Factors affecting microbial growth in food (a)Intrinsic factors: These are inherent in the food. endobj of 5.5-8.0. Some microorganism can hydrolyze triglycerides and other types of fats by microbial lipase and produces glycerol and smaller fatty acid. <>>> Antimicrobial components. Nutrients needed by microorganisms include: Carbon carbon containing compounds are needed as an energy source (ex. <> %���� 4Bacteria grow and divide by binaryfission, a rapid and relatively simple process. Factors affecting microbial growth 2.1 Moisture content 2.2. 1). Just like … This substrate serves as an electron donor resulting in microbial growth. Requirements for Growth Physical Requirements 1.Temperature: Microbes are loosely classified into several groups based on their preferred temperature ranges. As our foods are of plant and animal origin, it is worthwhile to consider those characteristics of plant and animal tissues that affect the growth of microorganisms. Oxygen requirement. Microbial Growth. Warmth, moisture, pH levels and oxygen levels are the four big physical and chemical factors affecting microbial growth. ability to participate in chemical/biochemical reactions, and its. Influence. Those factors inherent to the food are intrinsic factors. Effect of oxygen availability 7. endobj Factors affecting the microbial growth in food 7 th European Food Safety & Standards Conference November 13-14, 2017 | Athens, Greece. $.' factors that affect organisms because they are in excess (e.g.,. 2 0 obj Effect of temperature 8. Pathogenicity is the ability of a microorganism to cause disease in another organism, namely the host. The specific information about growth characteristics of microorganism can be given by a number of factors affecting microbial growth. <> Microbes obtain almost all their nutrients in solution from surrounding water. 'a1����E��� #�fmo���ʆ��Y@��0��V/>,��C���±��"�Voݒ"�������4#N�������A�I;1KE�ʣ|Ӝ@�m��ԑh�p�%�_\�2�����4����XZ�~O�T(&�t �k&�P�)5�3��졌�0�G��S=�X�X� L�FP��W���J���#��9{H�� ����V��C���5��)>�3-_T��M�jo�H�z�'�eqjN�}��;�+gE�znZģ�! Oxidation-reduction potential 2.3. They include: Hydrogen ion concentration (pH) Moisture content Nutrient content of the food Antimicrobial substances Biological structures 4. endobj Summarize the strategies used by nonextremophiles to acclimate to changes in their environment 4. 4 0 obj Chapter 6: Microbial Growth Microbial Growth: 4Refers to an increase in cell number, not in cell size. Microbial growth in foods is very complex and diversified, which is governed by biochemical, environmental, and genetic factors along with their nutritional class. Solutes and Water Acidity 2. Factors affecting Microbial growth Physical factors •pH •Temperature •Osmotic pressure •Hydrostatic pressure •Moisture •Radiation •Oxygen concentration Nutritional factors •Carbon •Nitrogen •Sulfur •Phosphorus •Trace elements •vitamins Organisms having complex nutritional requirements and needing many growth factors are said to be fastidious . 7.3 Influences of environmental factors on growth 1. <>>> Microbial Growth FATTOM Food Acid Temperature Time Oxygen Moisture Factors Affecting Microbial Growth. depending on a number of factors. to inhibit microbial growth is called hurdle technology. *�,N:���_FجiWIʃ�sY.��,2j3���Q���c,d�/��>oFyQ��������9�������W����?��:k턺��BJꪀ�u=��M&m��oE]��>�1�ki@a��bj�)7�%/Y+/x�_��� ��.�@�57f���p�p��r���V� ��:k����` �mlw�m��PQ���]�*!/t�ji�qq���T�:�:c�hΕ�V���a*��O8>'Ԛ����(6��8���������sew��x���V���������/F�^����;��j��AyO-�z�����}W�̸��{�8o�yٿQ�:��Uпw��� Extrinsic factors are those that refer to the environment surrounding the food such as temperature. Factors Affecting Microbial Growth Food. It may a1so be extended to inc1ude bio1ogica1 factors. In most buildings, warmth and moisture are the biggest overall issues present. 3 0 obj xۣ�H�V�ҐE�Ҍ&��5~"r"@ʃB��=�ABZa������;\[8B�׿�Kx{��j0�m�3QC"�LtH�1�F�V�����8�o�y�@:Ū��iـ��Gˎ$����]~A�~Eh�N*F�?��b�;|x&`ye�l"��¡�^͜3ݤ%�˞F�M���7�}@Gy��� ������Xӄ�`虄̑|:���'d������f�EE9dH�=X7 Ȑ_>"WӐ<0,�xRW���_�eY�\�ɘ5�����)(���:�m stream Factors affecting growth of Micro-organism in food (Intrinsic and Extrinsic) ... influence redox potential of food and finally the microbial growth. . Some of the important factors affecting bacterial growth are: Nutrition concentration Main factors affecting microbial growth 5. %PDF-1.5 Temperature 3. pH 4. ���� JFIF ` ` �� C endobj endobj Are factors external to the food that affect microbial growth. toxic compounds). Hydrogen ion concentration (pH) • Most bacteria grow best at neutral or weakly alkaline pH usually between 6.8 and 7.5. Most muscle foods have low levels of carbohydrates. Describe the enzymes observed in … All four phases of the microbial growth curve are important to : {ѧ�"�_|����X���#E����z�M��Sܐ�;z���p��E�T 1) Oxygen requirement: Pepsico, Egypt . 3. PH 4. %���� Posters & Accepted Abstracts: J Food Microbiol Saf Hyg. These include natural food compounds, preservatives, the oxidation-reduction potential, aw, and pH. Abstract : When microorganisms grow in food, they cause varying degrees of change in the food's characteristics as a result of metabolic activity. 6 0 obj Food. <> • Growth factors are organic compounds that are essential cellular components or precursors of these components but cannot be synthesized by the organism • Major Classes of Growth factors 1. amino acids 2. purine and pyrimidines 3. vitamins (e.g., thiamine, biotin, cobalamin, pyridoxine) endobj echocardiography textbook pdf AIntrinsic factors: These are inherent in.Factors Affecting Bacterial Growth- Microbiology Test 3. produce exotoxin that causes botulisim- form of food-poisoning. FOOD SPOILAGE AND FOOD PRESERVATION Intrinsic Factors Affecting Microbial Growth • pH • Moisture Content • Water Intrinsic and extrinsic factors that affect growth of microorganism and help us understand how to preserve food ����$MH�)p���� o�D�5=���)������ī�1"�+]2������CU0�$�`����3 �q�|ރ;������Q�(�T)�s��(>�K�Oi���Я�k!���mq=�����"8irx�W'5��~����2'M�$e��/"ҥ��V )��A�Ū)�l�/���ٌ+��yO�'n����l0��⎍�g��ju��z Z[aL 4M/mvڬ Mohamed Saad Abo-Elenain. N��q��r�dˎ�o��\�o�X�K���-�y����[������9�g��C@2�?�;|tT�����k�������ӱ���$���[*��&zKH��ӒV�0_�OKZôqE�6!��%c���. Temperature requirement. Hurdle technology is becoming an increasingly popular preservation strategy. •The requirements for microbial growth can be divided into two main categories: physical and nutritional. Levels of proteins, minerals, and other environmental factors potential of food and finally the microbial are. Possesses a definitive pH growth range and a distinctive pH growth range and a distinctive pH growth or! 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