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Microbes in food manufacture

  1. Applied Microbiology Microbes in food manufacture Dr. Aswartha Harinath Reddy M.Sc, Ph.D Department of Life Sciences Srikrishnadevaraya University Anantapur –A.P. India
  2. ROLE OF MICRO-ORGANISMS:  Food engineering is one of the advanced technology to improve the quality and quantity of food by using microorganism.  By food engineering, new food and high quality biological products can be prepared using microorganisms.  Also, in industries microorganisms are used to preserve food and destroys many pathogenic microbes and toxins.
  3.  The production and preservation of beverages like Ethanol, whisky, brandy, beer and rum are done by Saccharomyces cerevisiae (Yeast).  Lactobacillus sp in the production of different milk products.  Antibiotics like Penicillin is one of the important antibiotic is produced form Penicillium notatum.  Lipases, Proteases, Cellulases, Amino acids, Vitamins Produced from Aspergillus and Penicillium sp.  Some of the vaccines also produced form E. Coli. ROLE OF MICRO-ORGANISMS:
  4. Lactobacillus:  Lactobacillus is a genus of Gram-positive, facultative anaerobic or micro-aerophilic, rod-shaped, spore-forming bacteria.  Lactobacillus in food production: • Lactobacilli are important in the production of fermented dairy products [yogurt, cheese, kefir, koumiss, butter milk, pickles, beer and used as probiotic.
  5.  If lactic acid bacteria producing entirely lactic acid (homofermentation) as the major metabolic end-product is called Homolacticfermentation.  All members of the Lactobacilli, Streptococcus, Lactococcus and are homo-fermenters. Homo lactic fermentation:
  6. Hetero-lactic fermentation:  Lactic acid bacteria producing either a mixture of lactic acid, carbon dioxide, acetic acid and/or ethanol is called Heterolactic fermentation.  Some of the lactobacilli, while all Leuconostoc sp., as well as some Lactobacilli are heterofermenters.  . 
  7. Lactobacillus as Probiotics:  Lactobacillus sp. has been used as probiotic organisms.  Lactobacillus importance as probiotic it improves intestinal microbial flora.  L. acidophilus has been used because it was thought to be the dominant lactobacillus in the intestine.  However, a wide range of lactobacilli has been used in probiotic preparations. These include: L. bulgaricus, L. casei, L. brevis, L. lactis, L. fermentum, L. plantarum.
  8. Lactobacillus as Beneficial Microorganisms:  L. acidophilus and L. plantarum are beneficial microorganisms in the intestine, decrease the incidence of gastrointestinal disorders.  Lactobacillus sp. can produce anti- microbial substances, which have been observed to inhibit the growth of some pathogenic microorganisms.  Lactobacillus used as a food preservative to Control of Food Borne Pathogens.
  9. Lactobacillus as Vaccine Delivery Vehicles :
  10.  Cultured butter milk: Lactobacillus lactis, Streptococcus lacti.  Acidophilus milk: L. acidophilus.  Yoghurt: S. thermophilus, L. bulgaricus.  Kefir: S. lactis, L. bulgaricus.
  11. Yeast (Saccharomyces cerevisiae ):  Yeasts are eukaryotic, single-celled microorganisms classified as members of the fungus kingdom, typically measuring 3–4 µm in size.  Most yeasts reproduce by process known as budding.
  12.  By fermentation, the yeast species Saccharomyces cerevisiae converts carbohydrates to carbon dioxide and alcohols.  For thousands of years the carbon dioxide has been used in baking and the alcohol in alcoholic beverages.  It is also a centrally important model organism in modern cell biology research.
  13.  Many types of yeasts are used for making many foods:  Brewer's yeast in beer fermentation and Baker's yeast in bread production Alcoholic beverages:  Alcoholic beverages are defined as beverages that contain ethanol.  This ethanol is almost always produced by fermentation under anaerobic or low-oxygen conditions.
  14. Brewing yeasts may be classed as Top-cropping and Bottom- cropping.  Top-cropping yeasts are so called because they form a foam at the top culture during fermentation.  Ex: Saccharomyces cerevisiae.  Bottom-cropping yeasts are typically used to produce lager- type beers.  These yeasts ferment well at low temperatures.  Saccharomyces pastorianus.
  15. Baking agent:  Yeast, the most common one being S. cerevisiae, is used in baking as a leavening agent, where it converts the food/fermentable sugars present in dough into the gas carbon dioxide.  This causes the dough to expand or rise as gas forms pockets or bubbles. When the dough is baked, the yeast dies and the air pockets "set", giving the baked product a soft and spongy texture.  Brewer's yeast is also very rich in essential minerals and the B vitamins (except B12).
  16. Yeast extract:  Yeast extract is the common name for various forms of processed yeast products made by extracting the cell contents (removing the cell walls); they are used as food additives or flavoring, or as nutrient for bacterial culture media.
  17. Probiotics:  Some probiotic supplements use the yeast S. boulardii to maintain and restore the natural flora in the gastrointestinal tract.  S. boulardii has been shown to reduce the symptoms of acute diarrhea