microbial industry in food and beverages.docx

**Microbial Industry in Food and Beverages** **Microorganisms and Food** Microorganisms are a group of tiny (microscopic) organisms that live all around us (and on us) They usually fall into one of the three main groups: bacteria, viruses, fungi (e.g. yeasts and moulds) In many cases, these orga...

**Microbial Industry in Food and Beverages** **Microorganisms and Food** Microorganisms are a group of tiny (microscopic) organisms that live all around us (and on us) They usually fall into one of the three main groups: bacteria, viruses, fungi (e.g. yeasts and moulds) In many cases, these organisms are undesirable, as they make food spoil ("go off") or cause illness. However, some bacteria and fungi are commonly used to make food, viruses have no widespread use in food production. **History of microorganism use in foods** Microorganisms have been used to make food for millennia. Cheese, yoghurt, and bread all rely on fermentation by microorganisms in their production as do alcoholic drinks, such as wine and beer. It is thought that beer production may have started as early as the 7000 BC and cheese consumed as early as the 3000 BC The techniques used to make these products in modern times are more advanced and more carefully controlled, but the principles remain largely the same. **A Brief History** - Early food preservation - 900 AD: "Food Poisoning" recognized - 1795 -- Appert Developed canning - 1854 0 1864- Food microbiology becomes a science - Louis Pasteur **Why Study Food Microbiology?** - Provide clean, safe, and healthful food to consumer, - Food permits growth - Control of microbial growth - Prevent food spoilage - Prevent food-borne illnesses - Food preservation and production **Food-Borne Illness** - ERS Estimates \$6.9 Billion/year cost of FBI - CDC Estimates - 26 Million cases of FBI annually - 325,000 Hospitalizations - 5000 Deaths **Importance of Microorganisms in Foods** **Food Borne Diseases** - Many pathogenic microorganisms can contaminate food during various stages of their handling, between production and consumption. - Consumption of these foods can cause food borne diseases - Food borne diseases can be fatal and may also cause large economic losses - Foods of animal origin are associated more with food borne diseases than foods of plant origin **Food Spoilage** - Except sterile foods, all foods harbor microorganisms. - Food spoilage stems from the growth of these microorganisms in food or due to the action of microbial enzymes. - Major concerns: economic loss, food wastage - New concepts are being studied to reduce contamination as well as control the growth of spoilage microbes in foods. **Food Processing** - Many food grade microorganisms are used to produce different types of fermented foods using raw materials from animal and plant sources - Consumption of these foods has greatly increased over the last 15 to 20 years and is expected to increase further in the future, - There have been great changes in the production and availability of these microorganisms to meet the large demand. - Novel and better strains are being developed by using genetic engineering techniques **Food Additive** - Microbial enzymes are used to produce food and food additives. - By employing genetic recombination techniques and using diverse microbial sources, enzymes of higher purity and activity are obtained. - Many types of additives from microbial sources are being developed and used in food. - Include essential amino acids, color compounds, flavor compounds, stabilizers, and organic acids. **Food Bio Preservation** - Antimicrobial metabolites of desirable microorganisms are being developed and used in foods in place of preservatives. - Control pathogenic and spoilage microorganisms in food. - Economic production of these antimicrobial compounds and their effectiveness in food systems have generated wide interest. **Probiotics** - Live microorganisms used as food and feed supplement - "Live microorganisms which when administered in adequate amounts confer a health benefit on the host) - Act generally by improving or restoring the gut flora - Mainly bacteria, but certain types of yeasts can also function as probiotics. - Broad spectrum probiotics or multi-probiotics: combine different species in the same product - Probiotic food: yogurt, kefir, sauerkraut, tempeh, kimchi **Factors Affecting Growth of Microorganisms in Food** **Intrinsic Factors** - pH - Water activity - Redox Potential - Nutrient composition - Inhibitory Substances - Biological structures **Extrinsic Factors** - Relative humidity - Temperature - Atmospheric gases - Other microbial flora **Significance** 1. Food borne diseases of microbial origin 2. Microbial food spoilage 3. Beneficial uses of microbes in food 4. Control of microbial growth in foods 5. Destruction of microbes in food 6. Microbial food fermentation 7. Probiotic bacteria 8. Regulatory aspects to ensure consumers related to microbial hazards in food. **Applications** 1. Provides us with information about different types of microorganisms 2. Microorganisms as food 3. Microorganisms used in production of large numbers of fermented foods. 4. Microbiology: useful in food preservation 5. Microbial Diseases 6. Industrial Microbiology 7. Energy from microbial sources **Sample Applications** **Bread** - Bread has been a staple food item in many cultures for thousands of years. - There are different ways of making bread, some of which do not involve microorganisms, but most breads utilize yeast, which are single-celled fungi. - These yeasts ferment sugars to ethanol and CO2. The CO2 helps the bread rise. - Some breads (e.g. sourdough), also use bacteria called lactic acid bacteria, which provide the distinctive sour taste. **Dairy Products** - Many popular dairy products are produced with microorganisms. - Most cheese rely on bacteria to create a low pH and thereby help coagulate milk proteins. - Blue cheese contain moulds, which give them unique characteristics. - Various moulds, yeasts, or bacteria re added to the outside of cheeses to alter the final product, - Less well known fermented dairy products (e.g. kefir made from both bacteria and yeasts) are becoming more popular. **Alcoholic Drinks** - Alcoholic Drinks rely on microorganisms producing ethanol through fermentation, this is typically performed by yeasts. - Yeasts ferment sugars, forming ethanol and CO2. - Sometimes the CO2 is released, leading to a still drink. - Sparkling wines and many beers retain CO2, which helps to form bubbles or foam - Wine often rely on bacteria, which ferment malic acid into lactic acid, stopping the wine from tasting sour and unpleasant. **Soy-based products** - Used in a wide array of products, particularly in East-Asian cuisine. - Some of these products rely on fermentation Soy Sauce is made from soybeans that have inoculated with a certain species of mold. - Miso paste is made with the same mold and is used to make popular food item miso soup. - Tempeh is a solid product where soybeans are pressed into blocks and fermented by different species of mold. **Fermented Meat and Fish** - Common in some countries. - Some salamis are made with bacteria which can lower the pH of the meat and prevent spoilage, Some also use mold to cover the salami for protection. Not all salamis are made using fermentation. - Fish fermented by bacteria is more commonly eaten in some Scandinavian countries Central to South East Asia **Vegetables** - Kimchi: made from various vegetables fermented by bacteria. - Sauerkraut: fermented cabbage by bacteria naturally present in leaves. - Pickles: fermenting vegetables in brine. Bacteria can create acid which lowers the pH and preserves its contents. Many pickles are made by directly adding vinegar to reduce pH. **Condiments and sauces** A number of condiments and sauces rely on microorganisms for their distinctive flavors. These include: - Yeast extracts: created by destroying yeast cells which then digest themselves. - Worcestershire and fish sauce also fermentation for a richer flavor; - Vinegar, made using fermentation of various starting materials, such as wine, cider, fruit juice, by acetic acid bacteria. **Drinks** - Kombucha, thought to have been created in Eastern Russia/Northern Asia, is made by fermenting sweetened tea. It uses yeasts to break down sugars into ethanol and carbon dioxide and bacteria to break down the ethanol into acids. - This keeps the alcohol content relatively low and introduces a sour taste. - Kvass is a similarly produced drink popular in Eastern Europe and Russia. It is typically made from fermented rye and bread, with the addition of sugar, yeasts, and lactic acid bacteria. **Mycoprotein** - Meat alternative created from a fungus - Fungus is allowed to grow in large batches, before other ingredients are added to change the appearance and flavor of the final product. - By varying the ingredients added, mycoprotein can mimic many different existing meat products, such as sausages, chicken, or burgers. **Chocolate** - Comes from cocoa beans. Beans are not able to be used to make chocolate until they have been fermented. - Naturally occurring yeasts and bacteria process this over a period of 6-10 days, - The fermentation destroys the unwanted seed coating of the bed and prevents it from being able to grow. - Importantly, it also begins to forms some of the desirable flavors that are recognizable in chocolate.