5 Written questions
5 Matching questions
- Propionic acid
- Staphylococcus aureus
- 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.
- b prevent, slow spoilage. Dilemma, need to inhibit or kill microbes but agents can't be too toxic.
- c Organic acids. Produced by fermentation. Added to bread (Swiss cheese)
- d permitted for some foods. Will sterilize but can/will cause chemical changes in food. Creates peroxides that degrade proteins. End product: NH3 and amines. Degrade fats, short chain fatty acids. Was concern might create carcinogen.
- e (genus) bacteria associated with unpasteurized cheese and "pre-cooked meats"-hot dogs, deli meats
5 Multiple choice questions
- 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)
- 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.
- Disinfection after secondary treatment depends on next use. Causes fatal mutations
- 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.
- ultra high temp. Usually sterilized milk, if sealed, don't need to refrigerate.
5 True/False questions
120C → canning temperature needed for high acid foods (pH<4.5). Kills all vegetative cells. If spores survive, can't germinate at low pH
chlorine → 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
acetic acid → Organic acids-often naturally produced in fermented foods. Foods naturally preserved. (cheese)
secondary treatment → physical separation. Some "biosolids" sink, some floats: grease, oil. Skimmed off. Reducing total amount of organics remaining in water. Little microbial activity involve
flocculation → occurs throughout secondary treatment. Reduce pathogen by_________________