FSHN 101 Lecture Notes - Lecture 22: Exponential Growth, Microorganism, Thermophile

• School: University of Illinois
• Department: Food Science and Human Nutrition
• Course: FSHN 101
• Professor: Bohn Dawn

Document Summary

Good microbes= used to preserve foods and/or provide other desirable properties to food materials. Bad = cause unacceptable defects in appearance, flavor, and texture of foods, don"t make us sick though. Ugly = make us sick, food borne illness. Pathogenic make us sick, can"t develop in foods with a ph of less than 4. 6. Classes of micro differ in need for h20. Bacteria (. 09 aw) >yeast (. 86 aw) > mold (. 7) Size= small, 1 micron in length or diameter = can"t see. Unsafe pop= 10000 viable food infection microorganisms ** will u get u sick* Lag phase generation time= 60 min (1-2) Number of gen times required for switch from lag phase to log phase = 2 ( or existence of 4 viable food infection microorganisms) Go back an assign how long doubling takes. Total= 120+ 240= 360 min= 6 hours. Psychrotrophs: known as facultative psychrophiles- evolves to be able to grow at refrigerator temps.