ERF 215 PRINCIPLE OF FOOD MICROBIOLOGY.pdf

UNIVERSITY OF JUBA School Of Community Studies And Rural Development Depart Of Community Studies Specialization: Food And Nutrition  ERF 215 PRINCIPLE OF FOOD MICROBIOLOGY Ustaz Samuel Lemi Micah Bachelor of Science, “Honours”, Food & Nutrition(Ap...

UNIVERSITY OF JUBA School Of Community Studies And Rural Development Depart Of Community Studies Specialization: Food And Nutrition  ERF 215 PRINCIPLE OF FOOD MICROBIOLOGY Ustaz Samuel Lemi Micah Bachelor of Science, “Honours”, Food & Nutrition(Applied & Industrial Sciences, University of Juba), Masters in Public Health(MPH) (University of Juba(Pioneers)), Lecturer, School of Community Studies & Rural Development(Food & Nutrition), University of Juba  LEARNING OBJECTIVES Discuss the development of microorganism as a science Explain the roles of microorganisms in diseases, environment and food industry Explain prokaryotes and eukaryotes structures Explain the diversity of microorganisms: bacteria, fungi and viruses Explain laboratory techniques in microbiology  LEARNING OUTCOME Explain the basic concepts of principles of food microbiology  INTRODUCTION Microbiology is the study of microbes, a diverse group of generally minute life-forms that include bacteria, archaea, algae, fungi, protozoa, and viruses. Food microbiology is the study of microorganisms in food, how they affect food quality, safety, and health.  DEVELOPMENT OF MICROORGANISM AS A SCIENCE Microorganisms make up a huge part of the planet's living material and assume a significant part in keeping up with the Earth's environment. Microorganisms or microbes are tiny life forms that exist as unicellular, multicellular, or cell clusters. Microorganisms are inescapable in nature and are valuable to life, yet some can cause serious harm. They can be separated into six significant types: bacteria, archaea, fungi, protozoa, algae, and viruses. Cont. Life on Earth is renowned for its diversity. Microorganisms are found in each of the three domains of life: Archaea, Bacteria, and Eukarya. Microbes within Bacteria and Archaea are largely prokaryotes (their cells do not have a nucleus); while microorganisms in the domain Eukarya are eukaryotes (their cells have a nucleus). A few microorganisms, for example, viruses, are not categorized under any of the three domains of life because they don’t fit the traditional criteria for life. They lack fundamental characteristics of living organisms such as cellular structure and metabolism. Viruses are considered mobile genetic elements that replicate inside the cells of other organisms using the host machinery(cellular components) to produce viral particles. Cont. Microorganisms might be single-celled like bacteria and protozoa, or multicellular, like numerous algae and fungi. They live in a wide range of climatic conditions, ranging from ice cold environment to hot springs; and deserts to damp terrains. They are likewise found inside the body of humans and animals. A few microorganisms grow on different organisms while others exist freely(symbiosis). Microorganisms likewise make up the microbiota found in and on every multicellular organic entity. There is proof that 3.45- billion-year-old Australian rocks once contained microorganisms, the earliest direct evidence of life on Earth Cont. Microorganisms are significant in human culture and health, serving to ferment food sources and treat sewage, and to produce fuel, enzymes, and other bioactive mixtures. Microorganisms are essential tools in science as model organic entities and have been put to use in biological warfare and bioterrorism. Microorganisms are an imperative part of fertile soil. In the human body, microorganisms make up the human microbiota, including the essential gut microbes. The pathogens are responsible for many infectious diseases are microbes and, accordingly, are the objective of hygiene measures. Cont. Microorganisms can be found anywhere on Earth. Bacteria and Archaea are quite often microscopic, while various eukaryotes are also microscopic, including most protists, a few fungi. Viruses are not living and hence not considered as microorganisms, albeit a subfield of microbial science is virology, the study of viruses. Single-celled microorganisms were the first forms of life to develop on Earth, around 3.5 billion years ago. Further evolution was slow, and for around 3 billion years in the Precambrian era, all life forms were microorganisms. Microbes, algae and fungi have been recognized in amber that is 220 million years old, which shows that the morphology of microorganisms has changed little since Triassic period(lasting from 251-199million years ago). The newly discovered biological role played by nickel, may have accelerated the evolution of methanogens(archaea methane) towards the end of the Permian(299-251)–Triassic extinction. Cont. Microorganisms will in general have a moderately quick pace of evolution. Most microorganisms can replicate quickly, and bacteria are likewise ready to exchange genes through conjugation, transformation and transduction, even between divergent species. This horizontal gene transfer, combined with a high mutation rate and other means of transformation, permits microorganisms to evolve quickly to survive in new environments and respond to environmental stresses. This rapid evolution is significant in medication, as it has prompted the improvement of multidrug resistant pathogenic bacteria, superbugs, that are resistant to antibiotics.  THE ROLE OF MICROORGANISMS IN DISEASE Microorganisms play dual roles in diseases. While some are beneficial, aiding in digestion and immune defense, others are harmful pathogens causing infections like the common cold, tuberculosis, and malaria. Bacteria, viruses, protozoa, fungi, and worms can disrupt cellular activities, leading to diseases when they invade host cells. Understanding how these microorganisms cause diseases involves recognizing their ability to multiply, attach to target sites, evade the immune system, and obtain nutrients from the host. This intricate interplay highlights the complex relationship between microorganisms and disease development. DISEASES CAUSED BY MICROORGANISMS Some examples of diseases caused by bacteria, fungi, and viruses: Bacterial Diseases Strep throat Tuberculosis Tetanus Lyme disease Pneumonia Gonorrhea Gastric ulcers Fungal Diseases: Yeast infections Valley fever Meningitis Athlete's foot Ringworm Viral Diseases: Common cold Influenza HIV/AIDS Hepatitis Ebola hemorrhagic fever Herpes simplex Rhinovirus infections Coronavirus infections Bacteria, fungi, and viruses can all cause a wide range of infectious diseases, from relatively mild conditions like the common cold to severe, life-threatening illnesses. Understanding the differences between these microorganisms is crucial for proper diagnosis and treatment. Common Symptoms: Bacterial Infections: Redness, heat, swelling, fever, and pain at the site of infection. Swollen lymph glands. Fungal Infections: Rash and itching. Skin conditions and rashes. Viral Infections: Mosaic leaf pattern. Crinkled leaves. Yellowed leaves. Runny nose, muscle aches, and upset stomach. Control Measures: Bacterial Infections: Proper hygiene practices like frequent handwashing. Use of antibiotics as prescribed and completing the full course. Disinfection of areas with high bacterial concentrations. Fungal Infections: Keeping perishable food at the correct temperature. Avoiding sharing personal items. Viral Infections: Regular handwashing, especially before and after preparing food. Receiving recommended vaccinations and keeping them up to date. Avoiding close contact with infected individuals. Disinfecting surfaces in high-traffic areas. These control measures are crucial in preventing the spread of infectious diseases caused by bacteria, fungi, and viruses, and they play a significant role in maintaining public health and reducing the impact of these diseases on individuals and communities.  HOW BACTERIA,FUNGI AND VIRUS DIFFER IN DISEASE CAUSING Bacteria, viruses, and fungi differ in their ability to cause diseases due to their distinct characteristics: Bacteria: While most bacteria are harmless or even beneficial, some can cause diseases ranging from mild to severe, such as pneumonia, tuberculosis, and cholera. Bacteria are generally larger than viruses and can live and multiply independently. They have various mechanisms to cause diseases, like producing toxins or invading tissues directly. Viruses: Viruses are unique as they require a host cell to replicate. They are smaller than bacteria and consist of genetic material surrounded by a protein coat. Viruses can cause a wide range of diseases, from the common cold to HIV/AIDS, by hijacking host cells to reproduce and spread throughout the body  Fungi: Fungi, like yeasts and molds, can cause diseases such as athlete's foot and candidiasis. They are eukaryotic organisms that can decompose organic matter. Fungal infections often affect the skin or respiratory system and are particularly dangerous for immunocompromised individuals. Understanding these differences is crucial for diagnosing and treating infections caused by bacteria, viruses, and fungi effectively. THE ROLE OF MICROBES IN ENVIRONMENT 1- Nutrient Cycling and Decomposition Microbes are essential for breaking down complex organic matter and recycling nutrients like carbon, nitrogen, and phosphorus. They participate in processes like decomposition, fermentation, and respiration that return nutrients to the environment. Microbes are involved in soil formation and aggregation, improving soil structure and fertility. 2- Symbiotic Relationships: Microbes form mutualistic symbioses with other organisms, providing benefits like nitrogen fixation for plants. They can also have parasitic relationships, causing diseases in plants and animals. The complex interactions between microbes and their hosts are crucial for the functioning of ecosystems. 3- Bioremediation and Environmental Sustainability Microbes can degrade or transform various pollutants, playing a role in bioremediation of contaminated environments. They contribute to maintaining the balance and sustainability of natural ecosystems. Microbial activities are essential for the overall health and resilience of the environment. THE ROLE OF MICROBES IN FOOD INDUSTRY Microorganisms play a crucial role in the food industry, contributing to the production, preservation, and quality of various food products. Here are some key roles they perform: Fermentation: Microorganisms are used to ferment foods like dairy products, bread, vinegar, wine, and beer. This process involves the biochemical conversion of simple sugars into desirable compounds like alcohol, acid, and carbon dioxide. Food Preservation: Microorganisms are used to preserve food by inhibiting the growth of spoilage microorganisms. This is achieved through the production of antimicrobial compounds, such as antibiotics, and by creating an environment that is unfavorable for the growth of other microorganisms. Food Quality Improvement: Microorganisms can enhance the quality of food by improving its flavor, aroma, texture, and digestibility. For example, certain microorganisms can produce enzymes that break down complex nutrients into more easily digestible forms.  Food Safety: Microorganisms are used to ensure food safety by controlling the growth of pathogens and spoilage microorganisms. This is particularly important in the production of high-risk foods like meat, dairy, and vegetables. Production of Bioactive Compounds: Microorganisms can produce bioactive compounds like vitamins, enzymes, bacteriocins, and bioactive peptides that have health-promoting activities. These compounds can be used as nutraceuticals or functional foods. Food Engineering: Microorganisms are used in food engineering to improve the quality and quantity of food products. This involves the design and optimization of food manufacturing processes to enhance the nutritional value and shelf life of food.  Traditional Food Production: Microorganisms are used in traditional food production methods like fermentation, which has been practiced for centuries. This method is still used today to produce a wide variety of food products, including fermented vegetables, meats, and dairy products. Commercial Products: Microorganisms are used in the production of various commercial products like antibiotics, enzymes, and biofuels. These products are used in various industries, including pharmaceuticals, food processing, and energy production. In summary, microorganisms play a vital role in the food industry, contributing to the production, preservation, and quality of various food products. Their applications are diverse and range from fermentation and food preservation to the production of bioactive compounds and commercial products. Some common types of microorganisms used in food production include: Saccharomyces cerevisiae: Used in bread-making, beer brewing, and wine fermentation. Streptococcus thermophilus and Lactobacillus bulgaricus: Essential for yogurt production. Various species of Lactobacillus and Leuconostoc: Used in the fermentation of sauerkraut and pickles. Penicillium camemberti: Involved in the production of Camembert cheese. Various bacteria, including species of Propionibacterium: Used in the ripening of Swiss cheese. Penicillium roqueforti: Responsible for the production of Bleu cheese. Various yeasts, molds, and bacteria: Used in the production of bread, cheese, yogurt, and other fermented foods. These microorganisms play a vital role in food production processes, contributing to the fermentation, flavor development, and preservation of a wide range of food products. PROKARYOTES AND EUKARYOKES STRUCTURES The key differences in the structures of prokaryotic and eukaryotic cells are: 1- Nucleus Prokaryotic cells do not have a true nucleus. Their DNA is found in a central region called the nucleoid, which is not membrane-bound. Eukaryotic cells have a true nucleus surrounded by a nuclear membrane that encloses the cell's DNA. 2- Organelles Prokaryotic cells lack membrane-bound organelles like mitochondria, chloroplasts, endoplasmic reticulum, and Golgi apparatus. Eukaryotic cells contain a variety of membrane-bound organelles that carry out specialized functions. 3- Cell Size Prokaryotic cells are generally smaller, ranging from 0.1-5 μm in diameter. Eukaryotic cells are typically larger, measuring 10-100 μm in diameter. 4- Complexity Prokaryotic cells have a simpler cellular structure compared to the more complex organization of eukaryotic cells. 5- Genetic Material Prokaryotic DNA is circular and located in the cytoplasm, not enclosed in a nucleus. Eukaryotic DNA is linear and contained within the membrane-bound nucleus. In summary, the key structural differences are the presence or absence of a true nucleus, membrane-bound organelles, and the overall complexity of the cellular organization between prokaryotes and eukaryotes.  THE DIVERSITY OF MICROORGANISMS(BACTERIA, FUNGI,VIRUS) 1) Bacteria: Bacteria are single-celled microorganisms that exist in a vast diversity of shapes, sizes, and functions. They can be found in almost every environment on Earth, including extreme conditions like hot springs, radioactive waste, and the deep sea. Bacteria play crucial roles in various ecosystems, such as decomposing organic matter, nitrogen fixation, and symbiotic relationships with plants and animals. Some bacteria are harmful to humans, causing diseases like tuberculosis, cholera, and pneumonia. 2) Fungi: Fungi are eukaryotic organisms that are distinct from plants, animals, and bacteria. They are characterized by their ability to digest organic matter, produce enzymes, and form complex structures like mycelia and fruiting bodies. Fungi can be found in almost every habitat, including soil, water, and the air we breathe. They play essential roles in nutrient cycling, decomposition, and as symbionts with plants. Some fungi are harmful to humans, causing diseases like athlete's foot and yeast infections. 3) Virus: Viruses are the smallest known infectious agents, consisting of a piece of genetic material (DNA or RNA) surrounded by a protein coat. They cannot replicate on their own and rely on host cells to reproduce. Viruses infect all types of living organisms, including bacteria, archaea, plants, and animals. They can cause diseases ranging from the common cold to more severe illnesses like HIV/AIDS and Ebola. The diversity of viruses is vast, with new ones being discovered regularly.  LABARATORY TECHNIQUES IN MICROBIOLOGY Laboratory techniques in microbiology, covering a range of fundamental practices essential for studying microorganisms: Culturing Techniques: Methods for growing microorganisms in controlled laboratory environments. Aseptic Techniques: Procedures to prevent contamination and maintain sterile conditions during experiments. Identification Techniques: Processes for identifying different classes of bacteria and pathogens. Sterilization and Disinfection: Essential practices to eliminate or inhibit the growth of microorganisms in laboratory settings. Basic Microbiology Laboratory Procedures: Including staining techniques, biochemical tests, and serotyping. These techniques are vital for various applications in biological research, genetics, plant physiology, and molecular biology, contributing to advancements in healthcare, food production, and understanding microbial interactions. MORE TECHNIQUES TERMS 1) Inoculating agar plates: This is a method of introducing microorganisms onto a solid growth medium, such as agar plates, for the purpose of observing and counting their growth. The agar plate is first sterilized and then inoculated with a small amount of microorganisms, typically from a culture or a sample. The plate is then incubated under appropriate conditions for the growth of the microorganisms. 2) Inoculating broths: This is a method of introducing microorganisms into a liquid growth medium, such as a broth, for the purpose of observing and counting their growth. The broth is first sterilized and then inoculated with a small amount of microorganisms, typically from a culture or a sample. The broth is then incubated under appropriate conditions for the growth of the microorganisms. 3) Using hoods: This refers to the use of laboratory hoods, which are ventilated workspaces designed to protect the user and the environment from contamination. Hoods are typically used when working with potentially hazardous materials, such as microorganisms or chemicals Cont… 4) Serial dilution: This is a method of preparing a series of solutions with decreasing concentrations of a substance, typically a microorganism. Serial dilutions are used to determine the initial concentration of a microorganism in a sample or to prepare dilutions of a microorganism for use in experiments. 5) Plate counts: This is a method of counting the number of microorganisms present on a solid growth medium, such as an agar plate. The plate is first incubated under appropriate conditions for the growth of the microorganisms, and then a dilution of the medium is plated onto a new agar plate. The number of colonies that form on the new plate is used to estimate the number of microorganisms present in the original sample. 6) Most probable number: This is a method of estimating the number of microorganisms present in a sample. It involves serial dilution Cont. 1) Agar plate: An agar plate is a solid growth medium used for the cultivation, maintenance, and observation of microorganisms. It is made by dissolving agar, a polysaccharide derived from seaweed, in a liquid nutrient broth. The liquid is then poured onto a petri dish containing a solid agar base, and the dish is allowed to cool and solidify. The agar plate provides a suitable environment for the growth of microorganisms. 2) Grams staining: Grams staining is a method of staining bacteria that allows them to be differentiated based on their cell wall structure. It is named after the Danish bacteriologist Christian Gram, who developed the technique in 1884. In this staining method, bacteria are first treated with a solution of crystal violet, which binds to the peptidoglycan layer in the cell wall. The cells are then treated with a solution of gramicidin, which causes the crystal violet to be washed out of the live cells. The cells are then counterstained with a basic dye, such as safranin, which binds to the DNA in the cells. The stained cells can be observed under a microscope, and the presence or absence of the crystal violet stain allows them to be classified as Gram-positive or Gram-negative bacteria. 3) Motility: Motility refers to the ability of microorganisms to move spontaneously and actively in their environment. Bacteria can move by various means, such as flagella, pili, or gliding. The motility of bacteria can be observed under a microscope using a motility medium, such as a semisolid agar plate Cont… 4) Biochemical test: Biochemical tests are used to identify and characterize microorganisms based on their metabolic activities. These tests involve the use of specific substrates or reagents that are converted or consumed by the microorganisms. The results of these tests can help to identify the species, genus, or even the family of the microorganism. 5) Serotype: Serotype refers to the specific strain or Subtype of microbesas determined by the presence or absence of a specific ant.  THANK YOU SHUKRAN ASANTE SANA