Food Micro Lecture 4 Word Scramble
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| Give four examples of intrinsic factors. | Water activity, moisture content, pH, redox potential, antimicrobial constituents |
| Give three examples of extrinsic factors. | Temperature, relative humidty, concentration of gases in the environment |
| T or F: Inability to utilize a component in a food gives competitive advantage for that microorganism over others. | False |
| T or F: Molds require less nutrients than bacteria to grow. | True |
| ____ are more capable in converting complex molecules into simpler forms. | Yeasts and molds |
| All microorganisms require _____ to grow and metabolize. | water |
| T or F: Bound water is available for biological functions. | False |
| Define water activity. | Free/available water in food. |
| Name three things which can lower water activity of a food. | Salt or sugar addition, freezing, drying |
| Reducing water activity prolongs the _____ phase, lengthens the generation time in _____ phase, and lowers the max number of microorganisms in _____ phase. | lag, log, stationary |
| In an environment with low water activity, which growth functions are affected in the cell? | nutrient/waste transport, enzymatic reactions |
| T or F: Gram negative bacteria require a higher water activity than gram positive species. | True |
| T or F: In food with a higher water activity, yeasts and molds will predominate. | False |
| A low acid food has a pH > _____. | 4.6 |
| Most food have a pH < _____. | 7.0 |
| Give an example of a food buffer. | Milk |
| Give three examples of strong acids. | Hydrochloric, sulfuric, phosphoric acid |
| Most microorganisms grow best at a pH range _____. | 6.6-7.5 |
| T or F: Yeasts and molds grow at a lower pH than bacteria. | True |
| How should low-acid foods be treated? | With heat to destroy microorganisms and spores of health concern. |
| pH 4.6 is the minimum pH for _______ spores to germinate, grow, and produce toxin. | Clostridium botulinum |
| Water activity of 0.85 is the minimum for growth of ______. | Staphylococcus aureus |
| Define redox potential. | The ability of a substrate to gain or lose electrons. |
| Give two examples of foods with antimicrobial properties. | Egg whites, spices, milk |
| ____ can increase the heat resistance of C. botulinum spores. | Lysozyme |
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