5 Written Questions
5 Matching Questions
- acetic acid
- sorbic acid
- Propionic acid
- Listeria monocytogenes
- a 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)
- b Organic acids. Produced by fermentation. Added to bread (Swiss cheese)
- c Organic acids. Vinegar. Often added to veggies, meats, mayo (pickles)
- d Organic acids. Added to fruits, margarine, meat
- e (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 Multiple Choice Questions
- canning temperature needed for high acid foods (pH<4.5). Kills all vegetative cells. If spores survive, can't germinate at low pH
- Range of radiation sensitivity: Pseudomonas
- peak efficiency of aerobic microbes in reducing organics. Secondary treatment.
- Disinfection after secondary treatment depends on next use. Most effective way to remove giardia and cryptosporidium
- end product of anaerobic sludge digester. Organics will be fermented or organic acids + carbon dioxide. It is then converted to _________ by methanogens.
5 True/False Questions
intermediate → Range of radiation sensitivity: Lactobacillus
Radiation → prevent, slow spoilage. Dilemma, need to inhibit or kill microbes but agents can't be too toxic.
benzoic acid → Organic acids. Vinegar. Often added to veggies, meats, mayo (pickles)
63C for 30mins → low temp, long time (LTLT)
antioxidants → in body, we convert nitrites and nitrates to ______ which is CARCINOGENIC.