I am sending it to a few friends ans additionally sharing in delicious. And certainly, thanks in your effort! It is simple. Click on About us in top menu on opening the site. Select free e-courses and sign up the dialog box below the course of your choice and submit.
You will instantaneously get a link on your mail. Click on link and your request will be entered. You will receive the modules of the selected course after days each. Thanks for your interest. No products in the cart. Sign in Sign up. Search for:. Rajshree March 11, Microorganisms Microorganisms play an important role in food industry. Microorganism Growth and Food Spoilage Different food products provide different growth conditions for microorganisms.
Uses of Microorganisms in the Food Industry Currently, more than traditionally fermented foods exist in the world. Bacteria Bacteria are the largest group of unicellular microorganisms. Agriculture Food and Analytical Bacteriology Analytical microbiology is a study, application and use of microorganisms as reagents for the quantitative determination of certain chemical compounds.
Molds: Molds are multicellular filamentous fungi whose growth on foods is usually readily recognized by their fuzzy or cottony appearance. Yeasts: Yeasts have the ability to ferment sugars to ethanol and carbon-dioxide and hence they are extensively in food industry.
The other yeast strains of importance are Brettanomyces, Schizosaccharomyce,, Candida, Cryptococcus, Debaryomyces, Zygosaccharomyces, Hanseniaspora, Saccharomyces Factors Affecting Growth of Microorganisms To understand the uses of microorganisms in the food industry , it is imperative to understand how to use the microorganisms, as they tend to react differently in various conditions and environments.
Removing or destroying them by trimming, washing, heating, pickling. Adding chemicals like acid or alcohol or by encouraging competition to form organisms. Minimizing contamination from raw or unprocessed food, people, equipment, and the environment. Minimizing microbial growth by cleaning and sanitizing the equipment container etc.
Adjusting storage pH, light penetration, temperature, and other environmental factors. Points to remember Bacteria, molds and yeast are the most important microorganisms that cause food spoilage and also find the maximum exploitation in production of food and food products.
It is important to note that if any contaminated fodder is fed to animals, this is metabolized and the toxic derivatives can be found in animal products consumed by humans, e. Most commonly used microorganisms are yeast, bacteria, moulds, or a combination of these. A good example of microorganism usage in food production is the process of fermentation, which results in the production of organic acids, alcohols and esters. These help to either:.
Hygiene and epidemiology. Selected Chapters. ISBN Eva Kudlova, MD. Food hygiene. Klaenhammer TR Genetics of bacteriocins produced by lactic acid bacteria. Lee B Bacteria-based processes and products. In: Lee B ed Fundamentals of food biotechnology. Leroy F, De Vuyst L Bacteriocins of lactic acid bacteria to combat undesirable bacteria in dairy products.
Luche F Fermented meat products. Mayo B The proteolytic system of lactic acid bacteria. Microbiologia — PubMed Google Scholar.
Okereke A, Montville TJ Bacteriocin-mediated inhibition of Clostridium botulinum spores by lactic acid bacteria at refrigeration and abuse temperatures. Wiley, W. Sussex, pp 37—47 Google Scholar. Pritchard GG, Coolbear T The physiology and biochemistry of the proteolytic system in lactic acid bacteria.
Rafter JJ The role of lactic acid bacteria in colon cancer prevention. Ray B Fundamental food microbiology.
Microbiologia —64 PubMed Google Scholar. Rodriguez E, Tomillo J, Nunez M, Medina M Combined effect of bacteriocin-producing lactic acid bacteria and lactoperoxidase system activation on Listeria monocytogenes in refrigerated raw milk. Saarela MH Probiotic functional foods. In: Saarela M ed Functional foods: concept to product. Salminen S, Deighton M Lactic acid bacteria in the gut in normal and disordered states.
Salminen S, Salminen E Lactulose, lactic acid bacteria, intestinal microecology and mucosal protection. Sanders ME Phage resistance in lactic acid bacteria. Sievers M, Teuber M The microbiology and taxonomy of Acetobacter europaeus in commercial vinegar production. A lassi-like, salty drink called ayran is popular in Turkey and Bulgaria and is prepared by mixing yoghurt with water and salt.
In India, Bulgaria and Turkey yogurt is prepared at home using a small amount of plain active culture yogurt as the starter culture. The milk is boiled to kill undesirable microbes. A tablespoon of starter culture is added and mixed thoroughly. It is left undisturbed for about 6 hours. Cheese is a solid food made from the milk of various animals, most commonly cows. Milk from goat, sheep, reindeer and water buffalo may also be used. There are several types of cheese. Fermentation of milk leads to lactic acid production, which sours the milk.
This leads to coagulation of milk protein, casein. The solid part of the milk produced by coagulation is known as curd and the liquid is known as whey. The curds can be separated and pressed into desired shape and whey is used as food source for yeasts, which in turn can be processed as cattle feed and is rich in protein and vitamins. The cheese can be matured or ripened by the addition of bacteria or fungi or both.
The bacteria added reduce the pH, alters texture and develops a flavour. Coagulation can be controlled using rennet tablets, which contains the enzyme rennin. Rennin is an enzyme present in the stomach of Calves but now is also available in genetically engineered bacteria.
Coagulation can also be done using acids such as vinegar or lemon juice. Swiss cheese is prepared by the addition of Propionibacterium sharmanii. The big holes in the cheese is because of the production of large amounts of CO 2. The natural colour of cheese ranges from off-white to yellow. Herbs and spices may also be added to the cheese. Other factors that contribute to a different flavours and styles of cheese are different levels of milk fat, variations in length of aging, different processing treatments and different breeds of cows, sheep or other mammals.
Cheese is sold in the form as slices or in blocks or as a thick fluid. In addition, there is a class of cheese known as processed cheese or cheese food. Processed cheese is similar to cheese, but contains emulsifying salts acting as stabilisers. Some important food produced in whole or in part by microbial fermentation are pickles, sausages, etc. Different microorganisms are added to specific stages of food production to produce the desired effect. Moulds are used for the fermentation of rice to produce a variety of oriental foods.
Yeast is a fungus that feeds saprotrophically.
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