Chapter 28

1. Chapter 28 Applied and Industrial Microbiology

2. Foods & Disease • Because we distribute food that was prepared in central facilities the chance of widespread disease is more likely. • The USDA and FDA inspect these facilities to set standards for these facilities to prevent contamination. • The earliest forms of food preservation were: adding salt/sugar, fermentation, and drying.

3. The Role of Microorganisms in Food Production (MFP) CHEESE! • The milk protein casein curdles because of the action by lactic acid bacteria or the enzyme rennin/chymosin. -Cheese is the curd separated from the liquid portion of milk, called whey

4. MFP: Cheese Continued 2. Hard cheeses are produced by lactic acid bacteria growing on the interior of the curd -growth of microbes in cheese is called ripening 3. Semisoft cheeses are ripened by bacteria growing on the surface;

5. MFP: Other Dairy Products • Old-fashioned buttermilk was produced by lactic acid bacteria growing during the butter-making process -commercial buttermilk is made by letting lactic acid bacteria grow in skim milk for 12 hours

6. Sour cream, yogurt, kefir, and kumiss are produced by lactobacilli, streptococci, or yeasts growing in low-fat milk.

7. MFP: Nondairy Fermentations • Sugars in bread dough are fermented by yeast to ethanol and CO2; the CO2 causes the bread to rise • Sauerkraut, pickles, olives, and soy sauce are products of microbial fermentation

8. MFP: Alcoholic Beverages and Vinegar • Carbohydrates obtained from grains, potatoes, or molasses are fermented by yeasts to produce ethanol in the production of beer, ale, sake, and distilled spirits. • Sugars in fruits such as grapes are fermented by yeasts to produce wines

9. Fermentation Technology • Industrial Fermentation: • The large-scale cultivation of microbes or other single cells to produce a commercially valuable substance. • Also used in biotechnology to obtain useful products from genetically engineered plant and animal cells.

10. Fermentation Tech: Industrial Fermentation • Bioreactors: • Vessels for industrial fermentation and is designed with close attention to aeration, pH control, and temperature control. • Sometimes very large and can hold up to 500,000 liters.

11. Bioreactors

12. Fermentation Tech: Metabolite • Primary metabolite: • A product of an industrial cell population produced during the time of rapid logarithmic growth. • Secondary Metabolite: • A product of an industrial cell population produced after the microorganism has largely completed it’s period of rapid growth and is in stationary phase of growth cycle.

13. Fermentation Tech: Strain Improvement • Strain improvement is also an ongoing activity in industrial microbiology. • A well-known example is that of the mold used for penicillin. • The original culture of Penicillium did not produce penicillin in large enough quantities for commercial use.

14. Industrial Food Canning • Industrially canned goods undergo what is called commercial sterilization, by steam under pressure in a large retort which works like an autoclave. • Commercial sterilization is intended to destroy C. Botulinum, because if that endospore is destroyed, then any other spoilage or pathogenic bacteria will also be destroyed. • The 12D treatment is used to decrease the amount of C. Botulinum by 12 logarithmic cycles (1012). This treatment is considered safe because if there were 1,000,000,000,000 endospores in a can, there would be one survivor after the 12D treatment. • Thermophilic anaerobic spoilage is a fairly common cause of spoilage in low-acid canned foods. The can usually swells from gas, and the contents have a lowered pH and a sour odor. • When thermophilic spoilage occurs and the can isn’t swollen by gas production, the spoilage is called flat sour spoilage.

15. Radiation and industrial food Preservation.

16. Food can be sterilized completely by radiation. • The food sterilized by this method doesn’t become radioactive. • The taste of certain foods change after using radiation to sterilize it. • Irradiation treatment RESEMBLES PASTEURIZATION BY HEAT TREATMENT. • Using radiation on food kills parasitic worms, insects, and fruits and vegetables don’t sprout. • The kind of radiation used on food is cobalt-60.

17. Aseptic Packaging & The Future of Industrial Microbiology Chapter 28

18. Aseptic Packaging & The Future of Industrial Microbiology • Packages are usually made of materials that are tolerant to conventional heat treatment (laminated paper or plastic) • The packaging materials came into continuous rolls that are fed into a machine that sterilizes the material with hot hydrogen peroxide solution- sometimes aided by ultraviolet light. • Metal containers can be sterilized with superheated steam. • While still in the sterile environment, the material is formed into packages, which are filled with liquid foods that have been sterilized by heat.

19. Industrial Products Chapter 28

20. Amino Acids • lysine and methionine are amino acids that cannot be synthesized by animals. • In nature, microbes only produce the amount of amino acids needed. No excess will be made due to feedback inhibition. • Commercial amino acid production occurs in a lab where the microbe is manipulated to create more amino acids to be used.

21. Citric Acid • Citric Acids are in fruits such as lemons and oranges. • Citric Acid gives tartness to foods, serves as a pH adjuster and antioxidant. In dairy, it serves as an emulsifier. • Most commercially produced citric acid is produced by the mold, Aspergillus niger.

22. Enzymes • The production of amylases was the first biotechnology patent given by the U.S. • Enzymes are used in manufacturing foods, medicines and other goods that microbes produce.

23. Vitamins • Vitamins are tablets that are used as food supplements. • Most microbe species produce the majority of vitamins people take.

24. Pharmaceuticals • Most antibiotics were originally produced by microbes. Today, we can also synthetically produce antibiotics. • Vaccines are made by means of industrial microbiology. • Steroids can also be synthesized by microorganisms.

25. Copper Extraction • The metabolic activity of Thiobacillusferrooxidans is used to recover uranium and copper ores • An ore is a metal-bearing mineral or rock • Thiobacillus gets its energy from the oxidation of a reduced form of iron. This energy is used to recover copper ores.

26. Microbes as Industrial Products • Some microbes are purposefully produced in mass amounts to be used in production. • For example S. cerevisiae or (Baker’s yeast) is produced in large fermentation tanks. • After, the yeast is packaged into yeast cakes to be sold for baking at home.

27. Alternatative Energy Sources Using Microorganisms Organic waste, called biomass, can be converted by microorganisms into alternative fuels, a process called bio conversion. Examples of fuels produced by microbial fermentation are methane and ethanol.