Food Microbiology II- NFSC 278 Industrial Microbiology

1. Food Microbiology II- NFSC 278 Industrial Microbiology Principles of Food and Industrial Fermentations

2. What is meant by ‘Fermentation’ • In the biochemical sense: fermentation refers to a metabolic process in which organic compounds particularly CHO are broken down to release energy without the involvement of a terminal electron receptor as Oxygen

3. Fermentation • Partial oxidation of the substrate occurs & a small amount of ATP energy is released • Partial oxidation of CHO give rise to a variety of organic compounds • The compounds produced by microorganisms vary from organism to organism and are produced via different metabolic pathways

4. Industrial Fermentation • This term is applied to any industrial process that produces a material useful to humans if the process depends on the activity of one or more microorganisms • These processes are usually carried out in large scale • Some are fermentations in the biochemical sense but the majority are aerobic processes in which the microorganism uses Oxygen and metabolizes CHO completely

5. What is produced by Industrial Fermentation • Organic chemicals: fuels, food additives (Vinegar), antibiotics and enzymes for use in food and other industries • Organisms for the extraction of proteins: Single Cell Proteins (SCP) can be part of human diet (Quorn from fungus) in meatless dishes

6. What is produced by Industrial Fermentation • Yeast cells used in baking industry (baker’ s yeast) • Large scale production of cheeses, yoghurt and bread • Alcoholic beverages • Mushroom production

7. Fermentation Process Upstream Processing Production Microorganism Fermentation Raw Materials Fermentation Downstream Processing Product Purification Product Effluent Wastes

8. Fermentation Process • Production Microorganism: • obtain a suitable industrial microorganism • strain improvement to enhance productivity and yield • maintenance of strain purity

9. Fermentation Process Fermentation Medium: • cost-effective carbon and energy sources and other essential nutrients • many cases the basis of industrial media are waste products from other industrial process (sugar processing wastes, cheese whey and corn steep liquor)

10. What are Fermented Foods? • Are those foods produced by the modification of a raw material of either animal or vegetable origin by the activities of microorganisms • Bacteria, yeasts and mold can be used • Diverse range of products that differ in flavor, texture and stability from the original raw material

11. Production of fermented foods involved organisms that are biochemically fermentative • Examples: Lactic acid bacteria (CHO to Lactic Acid) • Yeast (CHO to Ethanol) • Molds (blue cheeses and soy sauce)

12. How did Fermented Foods Develop? • It is one of the oldest known methods of food preservation • Perishable foods spoil quickly, so the use of fermentation as a method of preservation started a chance contamination by organisms that produce acid • A food that kept much longer and had unique flavor

13. Organism involved were isolated, identified and cultured in the lab. • Pure cultures with known characteristics are called starter cultures • Starter cultures are added to raw materials to give fermentations that were more reliable and gave a consistent product

14. Benefits of Fermented Foods • Increase in variety of foods available: • Example: 1000 different types of cheeses • Use as ingredients for a variety of dishes: • Example: pepperoni in pizza and cheeses in many dishes

15. Improvements in nutritional quality: • Improves the nutritional quality of a raw material • Example: • Soybean to tempeh raises Vitamin B 12 • The presence of yeasts increase vitamin B

16. Benefits of Fermented Foods • Antinutritional factors such as phytates and lectins may be removed by the fermentation process • Fermentation may produce an increase in the availability of minerals • Preserves a raw material, improving safety with regard to food-borne pathogens • Increases shelf-life (milk compared to yoghurt)

17. Benefits of Fermented Foods Health Benefits: Examples: yoghurt can reduce serum cholesterol levels and helps avoid cancer Improve Digestibility: Example: People who cannot digest lactose properly can often consume fermented dairy products like yoghurts

18. Benefits of Fermented Foods Detoxification of raw materials: May remove toxic chemicals found in the raw material

19. Types of Fermented Foods • Acid Food Fermentations include: • Acid fermented dairy products: cheese, butter, yoghurt and kefir • Acid fermented vegetable products: sauerkraut, olives and various pickles • Acid fermented meat products: salami and pepperoni • Sourdough bread

20. Types of Fermented Foods Yeast Fermentations • Ability to produce carbon dioxide and ethanol • CO2 is important in the manufacture of leavened bread • Ethanol is metabolized in the production of beers, wines and spirits

21. Types of Fermented Foods • Solid State Fermentations: • Involve the use of a solid substrate into which the fermenting organism is inoculated • The organisms used are often molds

22. Types of Fermented Foods • Oriental Fermented Foods • Produced in Asia and Africa • Yeasts and molds are often the main organisms responsible • Examples: Soy Sauce (mold), Tempeh (legume-based)