5 Written questions
5 Matching questions
- bacillus cereus
- Propionic acid
- benzoic acid
- 72C for 15 sec
- a (species) bacteria that will grow in food. Secrete toxin. Causes vomiting, diarrhea. Source: soil bacteria in dust.
- b high temp, short time (HTST)
- c Organic acids. Produced by fermentation. Added to bread (Swiss cheese)
- d 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
- e Organic acids. Added to juices, jams, tomatoes, soda (salt)
5 Multiple choice questions
- high energy/ionizing radiation. Gamma rays. Knock electrons away from atoms. Creates very reactive free radicals that damage cell components. Kills cells
- chemicals added primarily to stop chemical oxidation. Stop oxidation of fats that yields short chain fatty acids (odor, taste problems). May also have anti-microbial activity.
- inverted 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.
- canning temperature needed for low acid food (pH>4.5). Spores will germinate at 100C, so need to use pressure and hotter water.
- Range of radiation sensitivity: clostridium and bacillus (spores)
5 True/False questions
sand filters → Disinfection after secondary treatment depends on next use. Most effective way to remove giardia and cryptosporidium
Listeria monocytogenes → (genus) bacteria associated with unpasteurized cheese and "pre-cooked meats"-hot dogs, deli meats
Pasteurization → 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)
secondary treatment → treating "clarified" water. COntains microbe, possible pathogens, dissolved organics, suspended organics.
90-95% → peak efficiency of aerobic microbes in reducing organics. Secondary treatment.