인간의 삶과 역사 속의 미생물

1. 인간의 삶과 역사 속의 미생물 강의자료ppt-6 2011-1학기

2. 미생물은어떤 존재인가?

4. 음식물과미생물

5. Microorganisms and food production

6. Fermented foods • Many common foods are produced or enhanced by the actions of microbes • Fermentation is the anaerobic catabolism of organic compounds (generally carbohydrates) • Important bacteria in the fermented food industry are lactic acid bacteria, propionic acid bacteria, and acetic acid bacteria • Products of fermentation include yeast bread, cheese, yogurt, buttermilk, sausage, sauerkraut, and soy sauce

8. Wine • Most wine is made from grapes • Wine fermentation occurs in fermentors ranging in size from 200 to 200,000 liters • Fermentors are made of oak, cement, glass-lined steel, or stone • White wine is made from white grapes or red grapes that have had their skin removed • Red wine is aged for months or years • White wine is often sold without aging

9. or Winemaking racking – removes sediments

10. Commercial wine making Equipment for Transporting Grapes to the Winery for Crushing

11. Comercial wine making Large Tanks Where the Main Wine Fermentation Takes Place

12. Commercial wine making Large Barrel Used for Aging Wine in a Large Winery

13. Commercial wine making Smaller Barrels Used for Aging Wine in a Small French Winery

14. Brewing, distilling and commodity alcohol • Brewing is the term used to describe the manufacture of alcoholic beverages from malted grains • Yeast is used to produce beer • Two main types of brewery yeast strains • Top yeast — ales • Bottom yeast — lagers

15. Lager beer and ales • Lager beer • Use bottom yeasts(e.g. Saccharomycespastorianus, S. carlsbergensis) • Fermentation: 8-14 days at 6-12oC • Aged several weeks at -1oC • Ales • Use top yeasts(Saccharomycescerevisiae) • Fermentation: 5-7 days at 14-23oC • Aged for short periods at 4-8oC * CO2 usually added at bottling * Beer can be pasteurized or sterilized by filtration

16. (pitched) Beer production

17. Brewing Beer in a Commercial Brewery The copper brew kettle is where the wort is mixed with hops and then boiled. From the brew kettle, the liquid passes to large fermentation tanks where yeast ferments glucose to ethanol plus CO2.

18. Brewing Beer in a Commercial Brewery If the beer is a lager, it is stored for several weeks at low temperature in tanks where particulate matter, including yeast cells settle.

19. Brewing Beer in a Commercial Brewery The beer is then filtered and placed in storage tanks from which it is packaged into kegs, bottles, or cans.

20. Distilled alcoholic beverages are made by heating previously fermented liquid to a temperature that volatilizes most of the alcohol • Whiskey, rum, brandy, vodka, gin

21. Distilled spirits: Dark rum, Brandy, and whiskey (left to right)

22. Ethanol production using Zymomonas • Zymomonas • A bacterium that carry out vigorous fermentation of sugars to ethanol • Used in production of fermented beverages (e.g. pulque in Mexico)

23. Korean traditional alcoholic beverages • 막걸리 • 동동주 • 기타 전통주: 홍로주, 문배주, 안동소주, 이강주, 복분자주, 가양주등

24. Citric acid and other organic compounds • Citric acid • A widely used food industry additive • Supplement in beverages, confections, and other foods • Used in leavening of bread

25. Fermentedmilks • Majority of fermented milk products rely on lactic acid bacteria belonging to the genera Lactobacillus, Lactococcus, Leuconostoc, Streptococcus, andBifidobacterium Lactobacillus helveticus Lactobacillus delbrueckii sub. bulgaricus Lactobacillus lactis Bifidobacterium

26. Cheese production milk lactic acid bacteria and rennin curd removal of whey ripening by microbial action  cheese

27. Major types of cheese and microorganisms used in their production

28. Brie cheese (soft/ripened; Penicillumcamemberti) Gouda cheese Limburger cheese (soft/ripened; Brebibacterium linens) Cheddar cheese cream cheese (soft/unripened) Roquefort cheese (goat cheese; Penicillium) Cottage cheese (soft/unripened) Swiss cheese (Propionibacterium)

29. Cheddar cheese production

30. Fermented meat and fish • Sausages • Hams • Bologna • Salami • Izushi – fish, rice, and vegetables (Lactobacillus spp.) • Katsuobushi – tuna (Aspergillusglaucus) • 가자미 식혜 • 젖갈

31. Production of breads • Involves growth of Saccharomycescerevisiae (baker’s yeast) under aerobic conditions • maximizes CO2 production, which leavens bread • Other microbes used to make special breads (e.g., sourdough bread)

32. Fermentedfoods produced from fruits, vegetables, beans, and related substrates 된장, 청국장, 고추장, 간장 등/ cocoa

33. Vinegar • Results from conversion of ethyl acohol to acetic acid • Incomplete oxidation of ethyl alcohol

34. Acetic acid bacteria • Commonly found in alcoholic juices • Some can synthesize cellulose (Acetobacterxylinum)

35. Diagram of a vinegar generator

36. Microorganisms as foods and food amendments • Variety of bacteria, yeasts, and mushrooms are used as animal and human food sources • Probiotics • microbial dietary adjuvants : e.g. Spirulina, lactic acid bacteria, etc. • microbes added to diet in order to provide health benefits beyond basic nutritive value

37. Benefits of probiotics • Immunodilation • Control of diarrhea • Anticancer effects • In beef cattle • Lactobacillus acidophilus decrease E. coli (O157:H7) • In poultry • Bacillus subtilis limit Salmonella colonization of the gut by the process of competitive exclusion

38. Bacteria as probiotics • Lactic acid bacteria • Lactobacillus and Bifidobacterium • addition of microbes to the diet to improve health beyond basic nutritive value Bifido-amended dairy products

39. Bacteria as probiotics • Spirulina

40. Algae as probiotics • Chlorella

41. Yeast as a food and food supplement • Yeast for baking or nutritional purposes are grown in aerated fermentor (醱酵槽) • Molasses (糖蜜) is the major ingredient of growth medium • Cells are recovered from broth by centrifugation • Compressed yeast cakes • Active dry yeast • Nutritional yeast

42. Stages in industrial production of yeast cells

43. Mushroom as a food source Agaricusbisporus The shitake mushroom, Lentinusedulus

44. Microorganisms and food spoilage

45. Spoilage of a dairy product

46. Spoilage of bread and corn Bread also can be spoiled by Bacillus species that produce ropiness Both are spoiled by fungi

47. Microbial growth and food spoilage • Food Spoilage • Any change in appearance, smell, or taste of a food product that makes it unpalatable to the consumer • Food may still be safe to eat, but is regarded as unacceptable • The chemical composition of a food determines its susceptibility to microbial spoilage • Perishable • Semiperishable • Nonperishable

48. Food classification by storage potential

49. Microbial growth and food spoilage • Susceptibility to food spoilage is based in large part on moisture content • Perishable foods have higher moisture content than nonperishable foods • Fresh foods are spoiled by both bacteria and fungi • Spoilage organisms are those that can gain access to the food and use the available nutrients • I.e., E. coli frequently contaminates meat products because it is found in animals’ digestive tracts

50. Food preservation • Methods for slowing spoilage and foodborne disease • Cold • Pickling and acidity • Drying and dehydration • Heating • Aseptic food processing • Chemical preservation • Irradiation