Microbes and food production


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Microbes and food production

  1. 1. Microbes and Food Production<br />Option F4 <br />
  2. 2. Saccharomyces and Food Production<br />Saccharomycesis a genus in the kingdom of fungi that includes many species of yeast. One of the most commonly used funguses in biotechnology is SaccharomycesCerevisiae. <br />Brewing Alcohol<br />Eg. Wine and beer <br />Wine and beer are brewed using yeast from the genus saccharomyces. <br /> <br />Alcoholic Fermentation in General: <br />* Fermentation is a chemical conversion of carbohydrates into ethanol and carbon dioxide. <br />When oxygen is absent, the yeast switches to anaerobic cell respiration aka fermentation<br /> <br />
  3. 3. Saccharomyces in Wine Production<br />1. Crush grapes to make juice, place into vessels or vats<br />-Yeast cells naturally present on the grapes<br /><ul><li>Selected varieties of yeast added to give special flavor</li></ul>2. Few days later the oxygen in the juice is used up <br /><ul><li>Yeast cells respire anaerobically</li></ul>3. Fermentation ends, Wine produces <br />-When all the sugar in juice is used up<br />- When ethanol content reaches 15% <br /> <br />* In the case of Champagne Production…<br />-Grapes picked earlier (low sugar, high acid) <br />- Finished wine is put into bottles with yeast and small amount of sugar for a second fermentation inside the bottle  trap CO2<br />
  4. 4. Saccharomyces in Beer Production<br />1. Barley grains germinate <br />AMYLASE is produced <br />2. Barley seeds dried after few days <br />Kill them and preserve the amylase <br />dried, semi-germinated barley seeds= MALTED BARLEY <br />3. Mix malted barley with other sources of starch, selected variety of yeast and water into a vat<br />-Hops added for flavoring <br />-amylase from malted barley digests starch to release MALTOSE<br />- Yeast converts to ethanol (anaerobic cell respiration) <br /> <br />* In the case of Guiness Beer Production… <br />-Barley is roasted before the fermentation (gives color and flavor) <br />- Healthier, less calories (198kcal) <br />
  5. 5. Saccharomyces in Baking<br />Smart way of saying “yeast” is…<br />SACCHAROMYCES<br />Fermentationtakesplace and releases Carbon dioxide and Ethanol. <br />Carbon dioxiderises thedough, increase its volume <br />Ethanol is evaporated <br />Oven heat eventually kills the yeastSTOP Fermentation. <br />
  6. 6. Saccharomyces in Soy Sauce Production<br />It takes6 months to make soy sauce.<br />It involves a fungus calledAspergillusOryzae(sounds and looks like asparagus, but apparently its not. So its kinda like asparagus spell from Harry Potter) <br />How to make: <br />Cook and mix with ground toasted wheat grains<br />2. Inoculate with asperigillus (produces immunity) <br />3. Few days later, transfer into vats with salt solution <br />4. Asperigillus ferments the starch and proteins into alcohol, organic acid, sugars and amino acid <br />5. Filter and pasteurize<br />BOOM HOME MADE <br />
  7. 7. Preservation of Food<br /> <br />Acid<br />Eg.Vinegar (contain ethanol acid) <br />- Microbes cannot grow at low pH <br />- Yoghurt made when bacteria convert lactose in milk to lactic acid reduce pH of milk preserve milk <br /> <br />Salt (Sodium Chloride) <br />- Added to create high salt concentration that microbes CANNOT grow <br />- Microbes killed in high salt concentration water is drawn out of them by osmosis <br /> <br />Sugar<br />Eg. HONEY <3 , Jam <br />- Honey is naturally preserved high sugar content <br />- If enough sugar, food can be preserved <br />
  8. 8. Food Poisoning<br />Most common form of food poisoning is caused by certain strains of: STAPHYLOCOCCUS AUREUS<br />General Symptoms: <br /> vomit, nausea, diarrhea within few hours <br />Method of Transmission:<br /> if the food contains strain of S aureus (in above 4 deg.)  bacteria multiply <br /> Eg.poultry, meat, egges, salads, puddings, sauces and bakery products containing cream<br />Treatment: <br />Aim:replace substance lost in diarrhea/ vomit <br />Oral Rehydration Fluids: dilute solution of mineral ions<br />Intravenous Fluid: only given when vomiting prevents rehydration<br />Antibiotics: only given if the infection is serious and has spread from the intestine into the blood <br />