The following points highlight the six main physical factors affecting the growth of microorganisms. FOOD SPOILAGE AND FOOD PRESERVATION Intrinsic Factors Affecting Microbial Growth • pH • Moisture Content • Water Chapter 6: Microbial Growth Microbial Growth: 4Refers to an increase in cell number, not in cell size. Adopting good housekeeping practices to reduce microbial growth . stream Factors affecting microbial growth 1. One indicator of microbial response is their taxonomic classification. The factors affecting microbial survival and growth in foods determine the nature of spoilage and any health risks. These include natural food compounds, preservatives, the oxidation-reduction potential, aw, and pH. The kinetics of microbial growth are covered in the third part of the chapter. stream f. Growth factors. %���� Other factors that control microbial populations are moisture content, dissolved oxygen, and temperature. Growth of bacteria is affected by many factors such as nutrition concentration and other environmental factors. •The requirements for microbial growth can be divided into two main categories: physical and nutritional. Effect of nutrient availability 6. 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. toxic compounds). <> The specific information about growth characteristics of microorganism can be given by a number of factors affecting microbial growth. Factors affecting the microbial growth in food 7 th European Food Safety & Standards Conference November 13-14, 2017 | Athens, Greece. $.' Factors affecting bacterial pathogenicity. <> Effect of water availability 9. Microorganisms generally have optimum and minimum levels of aw for growth depending on other growth factors in their environments. 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Solutes and Water Acidity 2. <> N��q��r�dˎ�o��\�o�X�K���-�y����[������9�g��C@2�?�;|tT�����k�������ӱ���$���[*��&zKH��ӒV�0_�OKZôqE�6!��%c���. • 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) 5 0 obj Intrinsic and extrinsic factors play very important roles to maintain a microbiologically safe food system. A microbe that is capable of causing disease is referred to as a pathogen. Summarize the strategies used by nonextremophiles to acclimate to changes in their environment 4. Factors affecting microbial growth 2.1 Moisture content 2.2. Influence. endobj Osmotic pressure (salt tolerance). : {ѧ�"�_|����X���#E����z�M��Sܐ�;z���p��E�T Organisms having complex nutritional requirements and needing many growth factors are said to be fastidious . glucose) for building blocks. Use the terms that describe a microbe’s growth range or requirement for each of the factors that influence microbial growth 2. 2. '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� Growth factors are organic compounds such as amino acids , purines , pyrimidines , and vitamins that a cell must have for growth but cannot synthesize itself. Food. <>>> Some of the important factors affecting bacterial growth are: Nutrition concentration Hence factors such as osmotic pressure and salt concentration of the solution affect the growth of bacteria. 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. INTRODUCTION Microbial growth is defined as increase in number of cells, not the size of the cells. to inhibit microbial growth is called hurdle technology. %PDF-1.5 Microbial growth, and, in some cases, the production of microbial metabolites, may be particularly sensitive to alterations in aw. The factors are: 1. Hydrogen ion concentration (pH) 2.4. Hydrogen ion concentration (pH) • Most bacteria grow best at neutral or weakly alkaline pH usually between 6.8 and 7.5. 2.4. endobj �5k��"�MiSV��Pm�*i����=�u��o� 4 0 obj %PDF-1.5 1 0 obj Pathogenicity is the ability of a microorganism to cause disease in another organism, namely the host. Dampness is a big player in the growth of fungi. <>/XObject<>/ProcSet[/PDF/Text/ImageB/ImageC/ImageI] >>/MediaBox[ 0 0 540 720] /Contents 4 0 R/Group<>/Tabs/S/StructParents 0>> Meats have abundant protein, lipids, minerals, and vitamins. Factors that. Requirements for Growth Physical Requirements 1.Temperature: Microbes are loosely classified into several groups based on their preferred temperature ranges. Temperature requirement. 3. 1) Oxygen requirement: factors that affect organisms because they are in excess (e.g.,. ",#(7),01444'9=82. In most buildings, warmth and moisture are the biggest overall issues present. 7.3 Influences of environmental factors on growth 1. 3 0 obj It is notable that each microbial species possesses a definitive pH growth range and a distinctive pH growth optimum (Fig. Describe the enzymes observed in … Most muscle foods have low levels of carbohydrates. 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. Extrinsic factors are those that refer to the environment surrounding the food such as temperature. Bacteria by virtue of mechanical strength of their cell wall are able to … ����$MH�)p���� o�D�5=���)������ī�1"�+]2������CU0�$�`����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 Biological structure 2.6. Factors Affecting Microbial Growth Food. 4Bacteria grow and divide by binaryfission, a rapid and relatively simple process. Microbial membrane are disrupted by temperature extremes. Just like … endobj ability to participate in chemical/biochemical reactions, and its. Effect of temperature 8. 1. At very low temperatures membranes also solidify and enzymes also do not function properly. Hurdle technology is becoming an increasingly popular preservation strategy. Are factors external to the food that affect microbial growth. Factors affecting bacterial growth are: 1. endobj endobj 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 Pathogens vary in their ability to produce disease. x��VKk�@����z�Z�h��`h���Ѓ�ډK�4��@}gVJ*�)�꥘(b5�of��������������0M�� Intrinsic and extrinsic factors that affect growth of microorganism and help us understand how to preserve food depending on a number of factors. Nutrient content 2.5. Microbial Growth FATTOM Food Acid Temperature Time Oxygen Moisture Factors Affecting Microbial Growth. Pepsico, Egypt . Foods such as … <> Warmth, moisture, pH levels and oxygen levels are the four big physical and chemical factors affecting microbial growth. Antimicrobial components. ���� JFIF ` ` �� C High temperatures damage microbes by denaturing enzymes, transport carriers, and other proteins. View food spoilage.pdf from PUPLIC HEA HSC 1104 at University of Guyana. <>>> Those factors inherent to the food are intrinsic factors. 6 0 obj 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. 2 0 obj Temperature is the most important factor that determines the rate of growth, multiplication, survival, and death of all living organisms. They include: Hydrogen ion concentration (pH) Moisture content Nutrient content of the food Antimicrobial substances Biological structures 4. endobj <> Posters & Accepted Abstracts: J Food Microbiol Saf Hyg. Temperature 3. pH 4. Summarize the adaptations of extremophiles to their natural habitats 3. Effect of oxygen availability 7. 2 0 obj 3 0 obj Metabolic processes Primary metabolism of an organic compound has been defined as the use of the substrate as a source of carbon and energy. Main factors affecting microbial growth 5. Microbes obtain almost all their nutrients in solution from surrounding water. 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. *�,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��� 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 Factors Affecting. 7 0 obj All four phases of the microbial growth curve are important to affect microbial growth in foods can be. The use of multiple environmental factors (i.e., pH, salt concentration, tem-perature, etc.) PH 4. It may a1so be extended to inc1ude bio1ogica1 factors. The plants and animals that serve as food sources have all evolved mechanisms of defense against the invasion and proliferation of microorganisms, and some of these remain in effect in fresh foods. Microbial cells obtain all required nutrients from food nearby. Abstract : When microorganisms grow in food, they cause varying degrees of change in the food's characteristics as a result of metabolic activity. Microbial growth in foods is very complex and diversified, which is governed by biochemical, environmental, and genetic factors along with their nutritional class. 1). Mohamed Saad Abo-Elenain. stream 1 0 obj endobj Introduction Intrinsic and extrinsic factors are both important to microbial growth. Plant foods have high concentrations of different types of carbohydrates and varying levels of proteins, minerals, and vitamins. 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Nitrogen needed for amino acids and nucleotides; some can synthesize … . of 5.5-8.0. x��Z�o�8��A��m͈�DJŢ�����aY`s����iz���ٶ���?L�&%u���-����7]\�Z|���/o~���.~���z���o�W�������.������/*�5g/t#/�6�gU�_�v~�~�T�~U6��^�e�x*�[�/r����Pn�z�\6�⺔vP�)��R/ Factors affecting growth of Micro-organism in food (Intrinsic and Extrinsic) ... influence redox potential of food and finally the microbial growth. <> availability to facilitate growth of microorganisms. <> Compounds affecting microbial enzymes (oxidative agents, chelating agents, heavy metals, antimetabolites) Compounds reacting with DNA ( chemical mutagenes – alkylating or deaminating agents, cytostatics) endstream Nutrients needed by microorganisms include: Carbon carbon containing compounds are needed as an energy source (ex. �Q�r��/��^ܕ�*��~~�#���:�j!Y#��/�����7E������N3- Microbial Growth. Factors affecting microbial growth in food (a)Intrinsic factors: These are inherent in the food. 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