9/18/2016 Food Learning Objectives Microbiology Increase awareness of the antiquity of newness of food Chapter 1 IN INTRODUCTION eaa The Trajectory of ·a8og Food Microbiology microbiology Understand the origins of food microbiology Food Microbiology:defined The Past 20 years A subdivision of microbiology ofoborephogens hs Study of microbes that grow in food "Safety through end-point testing"has Study on how food environments influence microbes testing time
9/18/2016 1 Chapter 1 The Trajectory of Food M crob ology icrobiology 1 Learning Objectives • Increase awareness of the antiquity of mi bi l lif d th f f d icrobial life and the newness of food microbiology as a scientific field • Fundamental discoveries in microbiology influence the practice of food m crob ology icrobiology • Understand the origins of food microbiology 2 Food Microbiology: defined • A subdivision of microbiology • Study of microbes that grow in food • Study on how food environments influence microbes 3 The Past 20 years • Number of foodborne pathogens has doubled • ”S f t th h d ”Safety through end-poi t t sti ” h s int testing” has given way to ”safety by design” provided by Hazard Analysis and Critical Control Points (HACCP) • Genetic and immunological probes have replaced biochemical tests reducing testing time • On the other hand, food microbiologists still study only the microbes seen under the microscope or grown on agar 4
9/18/2016 Societies for Food Microbiologist It is a microbial world American Society for Microbiology (ASM) -www.asm.org Microbes were here first and form the -aareas of microbiology foundation of the biosphere -27 division:12 scholarly journals Insitute of Food Technologists (IFT) Microbes will not be conquered nor -www.ift.org should they be all areas of food science Microbes exists without us but we -4 journals:short courses:public policy 。Tt cease to exist without microbes -www.foodprotection.org -exclusively food safety microbiology -2 journals on food protection Microorganisms have profound Microorganisms are Ubiquitous influence on all aspects of the earth and Dead see Found nearly everywhere its residents. Occur in large numbers influenced the Live in places other organisms cannot Evolution is the accumulation of changes Influence landscapes essential to life that occur in organisms as they adapt to their environment 学
9/18/2016 2 Societies for Food Microbiologist • American Society for Microbiology (ASM) - www.asm.org - all f i bi l ll areas of microbiology - 27 division; 12 scholarly journals • Insitute of Food Technologists (IFT) - www.ift.org - all areas of food science - 4 journals; short courses; public policy • International Association for Food Protection (IAFP) - www.foodprotection.org - exclusively food safety microbiology - 2 journals on food protection 5 It is a microbial world • Microbes were here first and form the f d ti f th bi h foundation of the biosphere • Microbes will not be conquered nor should they be • Microbes exists without us but we cease to exist without microbes 6 • Microorganisms have a profound influence on all aspects of the earth and its residents. • Microorganisms have influenced the evol i ut on of other life forms. • Evolution is the accumulation of changes that occur in organisms as they adapt to their environment 7 Dead Sea Found nearly everywhere Occur in large numbers Live in places other organisms cannot Microorganisms are Ubiquitous Hot Springs Influence landscapes essential to life 8
9/18/2016 Energy and Nutrient Flow within Decomposition and Nutrient Cycling Ecosystems Microbes break down dead matter and wastes into Ecosystems are communities of living organisms and their surrounding arvironment. Microorganisms are the main forces that structure Bacteria performed photosynthesis the content of the soil,water,and atmosphere. well before plants did. Photosynthesis is the light-fueled conversion of carbon dioxide to oxygen. te the majority of oxygen to the atmosphere. ragosi9P9 Microbes are Required for Human Health Humans have personalized microbial clouds. Aid digestion of foods Streptococcus ·Produce vitamins ·Proplonibacterium Prevent colonization of pathogens Aid homeostasis of our immune system MICROBIAL
9/18/2016 3 Ecosystems are communities of living organisms and their surrounding environment. Energy and Nutrient Flow within Ecosystems u un ng n nm n . Bacteria performed photosynthesis well before plants did. Photosynthesis is the light-fueled conversion of carbon dioxide to oxygen Photosynthetic ecosystem with algae mats oxygen. Microorganisms account for >70% of photosynthesis and contribute the majority of oxygen to the atmosphere. 9 Microbes break down dead matter and wastes into simple compounds/nutrients that can be reused in the natural cycles of living organisms. Decomposition and Nutrient Cycling Microorganisms are the main forces that structure the content of the soil, water, and atmosphere. Fungi on a decomposing log Garden compost Decomposing pig carcass 10 Microbes are Required for Human Health • Aid digestion of foods • Produce vitamins • Prevent colonization of pathogens • Aid homeostasis of our immune system 11 12
9/18/2016 Past and Present 4000 BC Fermentation of food is an organized activity Pasteur's Test of 1670 Hooke and van Leeuwenhoek observe microbes Spontaneous Generation Microbiology was born 1760 Spallanzani's boiled beef experiment creates a blow against spontaneous generation 1800 Appert invents the canning process in resporse to Napoleon's need to feed his troops 1810 Durand patents the tin can 1850 -Appert and Chevallier-Appert patent steam Curved Neck sterilization Pasteur shows living orga nisms involved in lactic and alcoholic fermentation rothis Boile Brotk Remains Free 1860 of Microoranisms Microorganisms -Pasteur disproves spontaneous generation-swan neck Grow in Broth Past and Present Koch's Postulates 1880 -Koch postulates bacteria as causative agents of 1.The same pathogen must be present in every case of the disease. agar 2.The pathogen must be isolated from the Gartner isolates Salmonella enterica from food diseased host and grown in pure culture. poisoning outbreak 1890 Pasteurization of milk begins in the US 3.The pathogen from the pure culture must 1900 Food and Drug Act is passed:Sinclair exposes the cause the disease when it's inoculated into a meat industry in The Jungle healthy,susceptible laboratory animal. 1920 -US Public Health Commission publishes method to 4.The pathogen must be isolated from the prevent botulism inoculated animal and must be shown to be the Flemming discovers antibiotics -Birdseye introduces frozen foods to retail market original organism
9/18/2016 4 Past and Present 4000 BC Fermentation of food is an organized activity 1670 Hooke and van Leeuwenhoek observe microbes Microbiology was born 1760 Spallanzani’s boiled beef experiment creates a blow against spontaneous generation 1800 Appert invents the canning process in response to Napoleon’s need to feed his troops 1810 Durand patents the tin can 1850 - Appert and Chevallier-Appert patent steam st ili ti terilization - Pasteur shows living organisms involved in lactic and alcoholic fermentation 1860 - Pasteur disproves spontaneous generation – swan neck experiment - Lister develops antiseptics for surgery 13 14 1880 - Koch postulates bacteria as causative agents of disease - Gram develops the gram stain procedure P i i h i di h d h f l f Past and Present - Petri invents the petri dish and the usefulness of agar - Gartner isolates Salmonella enterica from food poisoning outbreak 1890 Pasteurization of milk begins in the US 1900 Food and Drug Act is p p assed; Sinclair exposes the meat industry in The Jungle 1920 - US Public Health Commission publishes method to prevent botulism - Flemming discovers antibiotics - Birdseye introduces frozen foods to retail market15 Koch's Postulates 1. The same pathogen must be present in every case of the disease. 2. The pathogen must be isolated from the diseased host and grown in pure culture. 3. The pathogen from the pure culture must cause the disease when it's inoculated into a healthy susceptible laboratory animal healthy, susceptible laboratory animal. 4. The pathogen must be isolated from the inoculated animal and must be shown to be the original organism. 16
9/18/2016 Koch's Postulates Koch's Postulates 苦克 0→→→→ e meno meded i ese cases. rica th nmanmmuman 兰他高 ntrtble diseases oeeam Some microbes have never been cultured Gram Stain Past and Present bacte in i 1930 -Dack confirms Staphylococcus aureus makes toxin -Home refrigerators are introduced Food,Drugand Cosmetics Act aids regulation of Viruses are discovered 1940 Freeze-dried food is develoned -Supermarkets replace assorted shops 1950 -Watson and Crick discover DNA structure -Food irradiation research begins 1960 Duncan and Strong show that perfringens food poisoning is caused by a toxin -Fungal toxins are discovered 5
9/18/2016 5 Microorganisms are isolated from a diseased or dead animal Microorganisms are grown in pure culture. Microorganisms are inoculated into a healthy laboratory animal Disease is reproduced in a laboratory animal Microorganisms are isolated from this animal and grown in pure culture Koch's Postulates KEY CONCEPTS dead animal. laboratory animal animal. pure culture. Colony Microorganism from the According to Koch's postulates, a specific infectious disease is caused by a specific microbe. from the diseased host caused the same disease in a lab host. Microorganisms are identified. Microorganisms are identified. Microbiologists use these steps to identify causes of emerging diseases. Koch's postulates help determine the etiology of disease, the first step in treatment and prevention. 17 Koch's Postulates • Koch's postulates are used to prove the cause of an infectious disease • Exceptions to Koch's postulates and alternative methods are needed in these cases. – Some pathogens can cause several disease conditions, symptoms, and signs – Some pathogens cause disease only in humans – ethical issues with human experiments – Human experiments with untreatable diseases are not allowed today. – Some microbes have never been cultured 18 Gram Stain One of the most important staining techniques since it classifies bacteria into two large groups: grampositive and gram-negative Gram staining procedure: E. coli and Staphylococcus aureus 19 1930 - Dack confirms Staphylococcus aureus makes toxin - Home refrigerators are introduced F d D d C ti A t id l ti f Past and Present - Food, Drug and Cosmetics Act aids regulation of food - Viruses are discovered 1940 - Freeze-dried food is developed - Supermarkets replace assorted shops 1950 - Watson and Crick discover DNA structure - Food irradiation research begins 1960 - Duncan and Strong show that perfringens food poisoning is caused by a toxin - Fungal toxins are discovered 20
9/18/2016 Past and Present Past and Present 1970 Cohen discor recombination in bacter 2000 McKay repor ew Good ma ids in gram cturing practices are introduced for low-acid foods prenotification of imports Monocloral antibodies developed:foundation for First report of mad cow disease in the US antibody-based tests 1980 iosis geretic probe for Salmone/la detection polymerase chain reaction PCR was developed -Prions are discovered 1990 -Irradition approved for pathogen control in meat and poultry Mad cow disease seen in the UK HACCP is required by US Depart of Agriculture Food Spoilage Food Safety One-third of the world's 48 million in the US are food is lost to spoilage sickened by foodborne illnesses each year .9 billion people to feed by 2050 ·More than250 foodbor ·Hunger versus safety diseases are described =sick Fermentation may become ·Most are caused by bacteria,viruses,and foodborne more important in preserving food parasites Microbes may become a Globalization of food supplies creates new food source-yeast challenges for food safety
9/18/2016 6 1970 - Cohen discovers genetic recombination in bacteria - McKay reports plasmids in gram-positive bacteria - Good manufacturing practices are introduced for low acid foods Past and Present - - Monoclonal antibodies developed; foundation for antibody-based tests 1980 - first outbreak of literiosis -Escherichia coli O157:H7 identified as a pathogen - genetic probe for Salmonella detection - polymerase chain reaction PCR was developed - Prions are discovered 1990 - Irradition approved for pathogen control in meat and poultry - Mad cow disease seen in the UK - HACCP is required by US Depart of Agriculture 21 2000 - Irradiation is approved for shell eggs - Bioterrorism threats lead to new laws on facility registration, product traceability and prenotification of imports Past and Present - First report of mad cow disease in the US 22 Food Spoilage • One-third of the world’s f pg ood is lost to s poila g e • 9 billion people to feed by 2050 • Hunger versus safety • Fermentation may become more important in preserving food • Microbes may become a food source - yeast 23 Food Safety • 48 million in the US are sickened by foodborne illnesses each year • More than 250 foodborne diseases are described • Most are caused by bacteria viruses and bacteria, viruses, and parasites • Globalization of food supplies creates new challenges for food safety 24
9/18/2016 Changes in incidence of labora Foodborne infections and intoxications ·The causes for half of foodborne illnesses are unknown illnesses and deaths.2000-2008 ·Viruses estimated to cause 60%of foodborn illnesses STEC Nen O157 ·Role of unculturable microbes Role of unknown microbe and their gene pool? Cell-cell communication Still the same today 2014 FOOD SAFETY PROGRESS REPORT Scientific Innovations 2 Usually appear first as medical @ technology and then impacts the food system 回 Automated and food processing 回 Increased understanding of 回 a4 molecular mechanisms 回 ·Look at what is"hot"in biomedical areas as it becomes a part of food microbiology of tomorrow
9/18/2016 7 Foodborne infections and intoxications • The causes for half of foodborne illnesses are unknown • Viruses estimated to cause 60% of foodborn illnesses • Role of unculturable microbes • Role of unknown microbes and their gene pool? • Cell-cell communication Still the same today 25 26 27 Scientific Innovations • Usually appear first as medical technology and then impacts the food system • Automated and food processing facilities have adapted the methods for pharmaceutical houses • Increased understanding of molecular mechanisms • Look at what is ”hot” in biomedical areas as it becomes a part of food microbiology of tomorrow 28
9/18/2016 Metagenomics for food safety Wi DNA and RNA 。 Summary 1.Microbes were the first living things on earth and remain the foundation of the biosphere 2.Fundamental biological discoveries of the 1800's,such as disproof of spontaneous generation,Koch's postulates,and pure culture of microbes,continues to influence the field 3.Molecular biology and genetics have begun to have an impact on food microbiology and will shape its future 4.Food microbiology is young field of study
9/18/2016 8 29 30 Summary 1. Microbes were the first living things on earth and remain the foundation of the biosphere 2. Fundamental biological discoveries of the 1800’s, such as disproof of spontaneous generation, Koch’s postulates, and pure culture of microbes, continues to influence the field 3. Molecular biology and genetics have begun to have an impact on food microbiology and will shape its future 4. Food microbiology is young field of study 31