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5 Written questions

5 Matching questions

  1. sorbic acid
  2. listeria
  3. Staphylococcus aureus
  4. competition
  5. anaerobic sludge digester
  1. a (species) bacteria that grow in food, orginally from skin. Secrete toxin into food that induces vomiting and diarrhea. Self-limiting. Associated with SALTY foods.
  2. b Organic acids. Added to fruits, margarine, meat
  3. c take care of solids leftover from secondary treatment. Rate of digestion is slower than secondary, metaoblism is less efficient, but faster if warmer. Heated to 95-100F. Does reduce final volume of solid, Some molecules can only be decomposed by this. End product: carbon dioxide and METHANE
  4. d (genus) bacteria associated with unpasteurized cheese and "pre-cooked meats"-hot dogs, deli meats
  5. e pathogens are trapped in floc. They get killed by _________: intestinal microbes are not well adapted to this environment. Lose out by ____ for nutrients to "good bugs'

5 Multiple choice questions

  1. pathogens are trapped in floc. They get killed by _________: protozoans eat bacteria
  2. peak efficiency of aerobic microbes in reducing organics. Secondary treatment.
  3. Organic acids. Added to juices, jams, tomatoes, soda (salt)
  4. canning temperature needed for low acid food (pH>4.5). Spores will germinate at 100C, so need to use pressure and hotter water.
  5. brief exposure to high temperature. Can't be too long or changes the quality of food. Used mostly in milk. Kills ALL pathogens, and reduce number of spoilage bacteria (extend shelf-life)

5 True/False questions

  1. Injection of ozoneDisinfection after secondary treatment depends on next use. Very reactive, very damaging to living thing


  2. canninginverted by N.Appert, big prize from napoleon. Heating of food in bottles and seal it. Main concern now is growth from any surviving bacterial spores.


  3. acetic acidOrganic acids-often naturally produced in fermented foods. Foods naturally preserved. (cheese)


  4. Listeria monocytogenes(species) bacteria can grow at cooler temperature (psychrotrophic). Grow at fridge and body temp. Will cause infections and kill white blood cell. Eventually can reach the brain, can cause placenta. High mortality


  5. Propionic acidG.R.A.S. few resctrictions. Most will inhibit the uptake of key amino acids (key nutrients). All lower pH so enzymes won't work-inhibit growths.