5 Written questions
5 Matching questions
- sand filters
- Clostridium botulinum
- carbon dioxide
- a Disinfection after secondary treatment depends on next use. Most effective way to remove giardia and cryptosporidium
- b (species) bacteria found in soil. Anaerobic in can food. Causes paralysis
- c pathogens are trapped in floc. They get killed by _________: protozoans eat bacteria
- d 0-4C. Slows metabolism and growth. Extend shelf life but not forever. Does create good conditions for psychrophiles. Ex) lactobacillus, listeria, pseudomonas
- e part of secondary treatment in which microorganisms are used to reduce organics.
5 Multiple choice questions
- (species) bacteria that will grow in food. Secrete toxin. Causes vomiting, diarrhea. Source: soil bacteria in dust.
- occurs throughout secondary treatment. Reduce pathogen by_________________
- 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
- peak efficiency of aerobic microbes in reducing organics. Secondary treatment.
- Disinfection after secondary treatment depends on next use. Bleach, compressed gas. Very effective disinfectant that oxidizes everything such as proteins. Use at the end, inactivated by excess organics. Don't want to kill beneficial decomposers
5 True/False questions
competition → pathogens are trapped in floc. They get killed by _________: protozoans eat bacteria
Listeria monocytogenes → (genus) bacteria associated with unpasteurized cheese and "pre-cooked meats"-hot dogs, deli meats
72C for 15 sec → high temp, short time (HTST)
Propionic acid → G.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.
120C → canning temperature needed for high acid foods (pH<4.5). Kills all vegetative cells. If spores survive, can't germinate at low pH