Test Questions on Final Exam – Flashcards
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| How many different serotypes or species of salmonella are there? |
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| 30 |
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| Food spoilage can come from many microbial sources. What are some of them? |
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Moldy bread - fungi Contaminated meat - bacteria Shellfish - live in brackish water which has many toxins
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| What was the strain of salmonella that is associated with a breakout in a correctional facility that was traced back to Tyson's chicken? Why was this strain such a problem? |
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Heidelburg; pan resistant 75%
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| How long does it take the CDC/FDA to gain enough info to identify a strain associated with an outbreak/make a recall on food? |
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| 1-2 weeks |
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| How does the CDC/FDA identify the species of salmonella? What area of micro is associated with this? |
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| Identifications made by analysis of DNA. Molecular biology |
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| Who is most at risk for death from food poisoning? |
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| Young children and the elderly. Not a large killer of healthy individuals. |
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| Factors influencing microbial growth |
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Water content pH Physical structure Chemical composition O2 availability Temperature |
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Describe the requirement for microbial growth:
Water content |
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| Microbes need water. Very dry foods have less microbes |
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Describe the requirement for microbial growth: pH |
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| Neutral is more preferable |
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Describe the requirement for microbial growth: Physical structure |
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Ground beef has more microbes than steak. If a fruit or vegetable has a peel, it protects it better against microbes How food is stored is also important |
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Describe the requirement for microbial growth: Chemical composition |
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| Foods that are more acidic will have less microbial growth. |
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Describe the requirement for microbial growth: O2 availability |
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| Microbes need lots of O2 |
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Describe the requirement for microbial growth: Temperature |
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| Mesophilic |
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| What do molds breakdown? |
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| Carbohydrates |
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| Molds like a high ______ content |
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| sugar |
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The following foods are perishable/nonperishable:
fish, poultry, eggs |
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| Perishable; spoil quickly |
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The following foods are perishable/nonperishable: dry spaghetti, dry beans, coffee, raisins |
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| nonperishable; last a long time without going bad |
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| The consumption of _____ or ______ can cause food poisoning and infections |
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| toxins or microorganisms |
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Intrinsic or extrinsic?
Antimicrobial substances, some herbs tend to carry foodborne bacteria, polyphenol |
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| Intrinsic |
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| Intrinsic or extrinsic? |
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| temperature, humidity, contaminating organisms |
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| A toxin produced by aspergillus flavus that is cancer causing in vertebrates; linked to liver and colon cancers |
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| Aflatoxin |
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| What produces aflatoxins? |
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| Aspergillus flavus |
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| What is aflatoxin accumulated in? |
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| Grains, nuts, corn |
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| A condition inducing convulsions and hallucinations from fungal toxins in rye |
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| Ergotism |
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| What causes ergotism? And what famous historical event is it associated with? |
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| Claviceps purpurea; Salem witch trials |
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| Claviceps purpurea which causes ergotism, is found in what? |
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| Rye, wheat, barley |
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| What are some physical methods of controlling microbial growth in food? |
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| Filtering, refrigeration, freezing, heat |
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| This is used in deli meats. High volume of CO2 (60%) reduces the oxygen content in bacterial, therefore reducing gram negative bacteria on meat. |
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| Modified atmosphere packaging |
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| How does heating affect microbes? |
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| Heat kills microbes |
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| How does refrigeration affect microbes? |
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| Refrigeration slows the growth of microbes |
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What are the following known as?
Propionic acid Sorbic acids Benzoic acids Sulfites Sodium diacetate Sodium nitrite
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| Preservatives |
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Identify the preservative:
Prevents molds on bakery goods
inhibits enzymes by lowering pH
Preservative for both animal feed and food for human consumption |
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| Propionic Acid |
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| Inhibits enzymes by lowering pH |
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| Identify the MOA of propionic acid |
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Identify the preservative:
Natural organic compound All salts are associated with this preservative Prevents molds in cheeses, syrups, cakes Prevents growth of mold/yeast/fungi in food and drinks (pop and juices) |
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| Sorbic acid |
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Identify the preservative: prevents molds in margarine and low pH products |
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| Benzoic acids |
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Identify the preservative: Wines, lemon juices (NO meats) Dried fruits inhibits enzyme that causes "browning" Can potentially make allergies worse Antibacterial and antifungal SO2 |
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| Sulfites |
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| What is the enzyme that causes "browning"? |
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| Phenolase |
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Inhibit enzyme that causes "browning" |
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MOA of sulfites |
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Identify the preservative: Prevents molds on breads |
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| Sodium diacetate |
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Identify the preservative: Prevents botulism (clostridum) Inhibit iron-sulfur clusters Inhibits lipid oxidation Found in chicken and hotdogs Can form nitrosamine-this can be inhibited by vitamin C Do not consume when pregnant |
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| Sodium nitrite |
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| Inhibition of iron sulfur clusters which are essential to energey metabolism of Clostridium botulinum. Inhibits gram neg bacteria |
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| Sodium nitrite |
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| What is our concern with the use of sodium nitrite as a preservative? |
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| Nitrosamine formation; this occurs when the preservative is cooked and it combines with amino acids to produce nitrosamine which is a known carcinogen :( |
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| What can help prevent nitrosamine formation? |
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| Vitamin C; asorbic acid |
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Identify the preservative: Phenolase inhibitor Found with vitamin C as an antioxidant Derivatives prevent fat oxidation |
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| Citric acid and asorbic acid |
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| One of a group of bacterial proteins toxic to other bacterial cells. Produced by bacteria to kill bacteria (attach to plasma membrane and lyse cell) |
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| Bacteriocins |
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Identify the preservative: Produced from lactococcus lactis Contains bacteriocins which are an antibioitic compound that kills bacteria Found in lloyds pulled pork |
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| Nisin |
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| Contains bacteriocins which attach to plasma membrane of bacteria and lyse cell |
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| Nisin |
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Identify the food-borne disease:
Bacterial pathogen found in deli meats that causes food poisoning. Found mainly in prepackaged deli meats. Considering use of bacteriophage spray to reduce instances. |
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| Listeria |
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Identify the food-borne disease:
Norwalk virus. Named after Norwalk Ohio. Get it from food, direct/indirect contact. Found in shellfish and salad. |
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| Norovirus |
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Identify the food-borne disease:
Found in ground beef that is undercooked |
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| E.Coli 0157:H7 |
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Identify the food-borne disease:
Toxin producer found in eggs |
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| Shigella |
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Identify the food-borne disease:
Found in shellfish, causes GI disease |
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| Vibrio parahaemolyticus |
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All the following foods are an example of what?
Milk products, meat/fish, alcohol, breads, tofu, tempeh, pickles/kraut, soy sauce, kimchi |
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| Foods fermented by microbes |
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| Bacteria involved in making cheese. Also found in buttermilk, sour cream, and keifer |
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| lactobacillus, lactococcus lactis |
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| Where does milk pick up bacteria? |
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| Sterile in cow's udder, picks up bacteria in the milking process |
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| This is what you innoculate foods with. Isolated bacteria. Many people retain small amounts of previously made yogurt, cheese, etc. |
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| Culture/starter |
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| How do lactobacillus and lactococcus lactis work? |
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| They ferment lactic acid from lactose |
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| How do cultures/starters affect food? |
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| Lower pH |
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| What is the liquid part of cottage cheese/yogurt called? |
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| Whey |
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| When milk curdles to form cheese or cottage cheese, what is produced and what is formed? |
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| Acid is produced and caseinase is formed |
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| What is the sugar found in milk |
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| lactose |
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| What is the #1 species for making cheese? |
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| Lactococcus lactis |
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| Mongolian. Kept in leather bag which is easy to keep fermented. Can have some alcoholic content |
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| Kefir |
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| What must you first do with milk or sour cream before innoculating it? |
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| Boil to kill bad bacteria |
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| Contains more protein and less whey. More compacted. Also contains a different strain of lactococcus |
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| Greek yogurt |
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Contains streptococcus thermophilius and lactobacillus bulgariucs; like around 75-80 degrees celsius.
Created through a thermophilic process
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| Yogurt |
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| Where do microbes originate in foods like sausage, salami and pepperoni? |
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| Microbes comes from casings and environments in which the food is made |
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| _______ foods are more easily preserved, known to have a high number of vitamins, easily digestable, antioxidants, probiotics |
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| Fermented foods |
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| Yeast does fermenting. Do not want bacteria involved or present. Produces carbon dioxide gas during process |
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| Production of Ethanol/Alcohol |
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| What is important when fermenting alcohol? |
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No bacterial contamination No air otherwise the yeast will produce ethanoic acid which is the chemical in vineagar |
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| If air is allowed in fermentation of alcohol, what will be produced? |
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| Ethanoic acid - chemical found in vinegar |
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| What is the beer starter known as? |
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| wort |
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| What is involved in the making of bread? |
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| Fermentation; yeast is mixed with dough and kept warm. Carbon dioxide makes the bread dough rise and alcohol evaporates |
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| Set of freeze dried bacteria that will activate when they reach the colon |
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| Probiotics |
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Must not be pathogenic or carrying resistance genes Must be able to get past acidic environment of the stomach Very strict regulations |
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| Probiotics |
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| These are given preemptively to cattle, chickens to prevent campylobacter and salmonella. |
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| Probiotics |
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| What kind of microbes do the work of composting? |
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| Aerobic microbes |
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| How long must composte be treated in order to be usable at OU? |
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14 days inside composting machine 90 days outside |
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| What must be present inside the in vessel composter at OU for composting to happen? |
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| Needs air. Has a lot of fans to keep O2 going so that microbes and other organisms are kept alive |
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| What goes into the composter here at OU? |
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Paper Food waste Service ware PLA Bulking agent (mulch, etc.) |
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| Process by which organic substances are broken down into smaller compounds by living microbial organisms |
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| Biodegradation |
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| What is the gas produced from landfill waste? |
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| Methane |
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| What gives earthy smell to compost? |
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| Actinomycetes |
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| What microbes do the work of composting? |
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Mesophiles: lactobacillus spp acetobacter As it heats up, thermophiles take over: bacillus spp and actinobacteria |
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| What should end product of compost not contain? |
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| Pathogens or viable seeds |
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| EPA waste diversion mandates that federal agencies must reduce waste by ____ by fiscal year 2015. |
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50%
States mandate states |
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| How many tons of food are produced each day at OU? |
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| 6 tons daily |
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| A corn/starch based bioplastic that can be broken down in a landfill in 14 days compared to the 1,000 years of other plastics that arent treated |
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| Plastarch material |
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| Organic substances are broken down into smaller compounds by living microbial organisms |
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| Biodegredation |
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| Bacteria ferments sugar by bacteria and turns it into lactic acid. Lactic acid beads are then formed into products. This is biodegradable. Cannot be heated! |
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| PLA plastic |
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| Why do we need biodegradable plastic? |
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| 2 large patches in each ocean of garbage approx size of pennsylvania. These flow and vortex in oceans. Contain hundreds of microbes that help break down plastic-many vibrio species |
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| Water borne pathogens; fecal contamination |
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| Coliforms |
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| Indicator species of fecal contamination; most common? |
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| E.Coli |
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| What is the 3 step process of water purification? (drinking water) |
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Sedimentation Filtration Chlorination |
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Identify the process of drinking water treatment:
Removes large objects and particles through flocculation |
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| Sedimentation |
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Identify the process of drinking water treatment:
Removes microorganisms by passing water through a layer of sand, gravel, microbe biofilm, carbon |
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| Filtration |
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Identify the process of drinking water treatment:
Involves addition of chlorine gas to kill remaning organisms |
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| Chlorination |
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| What are the two techniques used to determine numbers of bacteria in a water sample? |
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| Membrane filter technique, standard plate count (SPC) |
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| Test determines number of bacteria by observing carbon dioxide gas production |
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| Most probably number (MPN) |
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| Who regulates water quality? |
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| EPA |
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| What is acceptable level of coliforms for drinking water? |
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| Less than 1 coliform per 100 ml's |
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| If coliforms are found in more than ___% of drinking water, quality isnt accepted |
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| 5% |
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| What are the three steps in sewage treatment? |
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| Screen, sediment, sludge. Ends with chlorination |
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| What happens once waste water is turned to sludge? |
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| Done aerobically and anaerobically; can be turned into fertilizer or dried and buried |
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| What are the 3 biochemical cycles? |
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Carbon Nitrogen Sulfur |
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| What do soil microorganisms do? |
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| Break down organic molecules from dead and dying things |
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| These organisms convert Co2 into carbohydretes - carbon fixation |
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| Photosynthetic organisms |
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| What retains most of the carbon in our atmosphere? |
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| Oceans |
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| Convert dead organic matter to release CO2 for reuse by plants |
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| decomposers |
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| What must atmospheric carbon be kept at to keep global warming at halt? |
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| 350 ppm's |
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| What is climate change caused by? |
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| Carbon levels |
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| How much carbon you used in your lifetime |
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| Carbon footprint |
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| Atmospheric carbon contributes to what? |
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Greenhouse effect acid rain |
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Causes breakdown of coral reefs pH of oceans will affect this a lot Acid rain on mountain tops; ruins soil and causes trees to dry out and die |
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| Acidification |
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| What is a source of local acidification? |
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| Acid mine drainage. Water that comes through them becomes polluted and pollutes water sources. This kills fish, microinvertabrates, causes dead patches in streams |
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| What must both drinking water and sewage water undergo before going back into the system? |
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| Chlorination |
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| Excess nitrates (NO2) and sulfates (SO2) cause pollution. What type of pollution is this? |
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| Sulfur pollution |
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| Excess nutrients are feeding microbes and large algal blooms are created. WHen they die cause excess organic material to collect on the bottom |
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| Dead zones |
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| Level of O2 in water that will sustain life |
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| BOD |
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| Make low pH water neutral pH once it gets through system. Microorganisms in the shallow water and muck use anaerobic metabolism use alternate electron acceptors such as nitrate/sulfate |
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| Buffer zones |
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Uses a muck sample to analyze for microorganisms Compares sulfur oxidation, photosynthesis, etc Put in muck, sulfur sample, and pond water Anaerobes at bottom photosynthesizers at top 2-3 months incubation |
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| Winogradiski Column |
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| Helps to clean up pollution naturally using microbes. Reduce PCB's and TCE (Known carcinogens) |
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| Bioremediation |
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| Have to be careful that microbes released wont affect other organisms. These unintended effects are known as what? |
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| Non-target effects |
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| What species are pivotal in the cleaning up of oil spills? |
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| Pseudomonas |
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| During this process, organic compounds are converted to inorganic compounds |
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| Mineralization |
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| Microbes release what substance? |
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| Nitrogen |
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| Beginning of nitrogen cycle. Breakdown of dead and decaying material into ________. |
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| Ammonification; ammonia |
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| What is broken down into ammonia during ammonification? |
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| Urea |
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| Second step of nitrogen cycle following ammonification. It is a 2 step process. Converts ammonia to nitrite and then nitrite to nitrate |
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| Nitrification |
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| During the first step of nitrification; what happens? And what species carry it out? |
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Ammonia to nitrite. Nitrosococcus Nitrosomonas |
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| During the second step of nitrification; what happens? What species are responsible? |
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Nitrite to nitrate
Nitrococcus Nitrobacter |
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Third step of nitrogen cycle following nitrification.
Involves taking nitrate to nitrogen gas. This replenishes the atmosphere |
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| Denitrification |
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| What species carries out denitrification? |
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| Pseudomonas |
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| What is the bad greenhouse gas that can be given off by denitrification? |
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| Nitris oxide |
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| Taking nitrogen gas and converting it to organic nitrogen. |
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| Nitrogen fixation |
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| What species carries out nitrogen fixation? |
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| Rhizobium (bacteria) Legumes, clover have pockets called nodules (located in roots) that contain this. |
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| Fungal symbiotic relationships with plant roots. Make plants more efficient in absorbing nutrients |
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| Mycorrhizae |
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| Plant pathogen (bacteria) that causes tumor to form by horizontal gene transfer. The bacteria affects DNA in plants (bacterial DNA found in nucleoid region) creates pili between bacteria and plant cell. Will express virulent DNA which produces massive growth in tissue. |
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| Agrobacterium |
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| What does virulent DNA that causes tumor growth in plants produce that is helpful to harmful bacteria? |
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| Opines |
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| Scientific model for GMO's Do experiments on this much like we test meds on mice |
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| Arabidopsis Thalliana |
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| What is the photosynthetic part that plants possess? |
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| Chloroplasts |
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| What was the first photosynthesis carried out by? |
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| Cyanobacteria |
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| How many phases does photosynthesis have? And what are they? |
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| 2 phases; light and dark |
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| In this phase of photosynthesis; plant absorbs energy from the sun. Shifts around electrons through an ETC. NADPH and ATP created travel to calvin cycle. CO2 fixed into larger carbohydrate and releases O2 |
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| Light cycle |
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| What is created in the light phase of photosynthesis? |
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| NADPH and ATP |
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| In this phase of photosynthesis, CO2 is incorportaed into sugar. Energy from other phase drives this |
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| Dark phase |
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| One celled euk. photosynthesizers |
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| Algae |
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| What do photosynthetic bacteria have? |
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| Thylakoids |
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| This is found with cyanobacteria in marine ecosystems |
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| microalgae |
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| Zoo plankton. Symbiotic relationships between larger animals that provide nutrients heterotrophic or photosyntheic |
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| Zooxanthaellae |
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| Biological phenomenon that indicates growth in response to an environmental stimulus |
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| Tropism |
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| Tiny organism that lives within dinoflagellates |
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| Roseobacter clade |
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| What does the sulfur smell of the ocean come from? Other ocean smell? |
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| Dinoflagellates. DMSP |
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| In earthworm group. Live near hydrothermal vents where no sunlight is present. Surround water is very cold but vents are very warm |
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| Hydrothermal vent tube worms |
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| Have no digestive system. Have a symbiotic relationship with bacteria that live in trophosomes and feed them. Discovered by Colleen Cavanaugh |
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| HTV Tube worms |
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| Only eat wood (carbon/cellulose) have many bacteria/archea/protists that help it digest it and allow them to use it as a nutrient source. Contain nitrogen fixing bacteria that converts nitrogen gas to organic nitrogen |
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| Termites |
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| Complex parasitic euk. that wouldnt be symbiotic without bacteria. |
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| Nematodes |
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| C. elegans is what? |
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| Eukaryotic cell model; behave similarily to human cells |
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| When using bio control, we want to consider these because their effects are often much more damaging than predator-prey interactions |
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| Nematodes |
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| HB bacteria interacts with these. Live inside them and fluoresce. Virulent bacteria that kills caterpillars in 24-48 hours. |
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| Nematodes |
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| An association between a fungal mycelium and a cyanobacterium or alga |
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| Lichens |
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| Lichens are composed of what 2 organisms? |
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| Fungi and cyanobacteria |
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| Where do lichens grow? What do they replenish? What are they good indicators of? |
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| Rock and stone. Break them down into soil. They replenish soil. Good indicators of pollution because they do not grow well in areas that are highly polluted. |
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| Microbes that glow are said to what? |
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| Bioluminesce |
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| Sea water vibrio that helps squid to glow because of the light this bacteria gives off. Helps the squid to appear to be a part of the night sky when the predators look up at it. Camo! |
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| Vibrio Fischeri |
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| "Cud chewers" cows, sheep, deer. 4 chambers to stomach. Regurgitate food and chew again |
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| Ruminants |
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| If the diets of ruminants are changed suddenly, what can affect them that is potentially fatal? |
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| Acidosis |
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| In humans these form a symbiotic relationship |
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| Gut microbiota |
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| An interrelationship between 2 populations of organisms where there is a close and permanant association |
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| Symbiosis |
