Save
Busy. Please wait.
or

show password
Forgot Password?

Don't have an account?  Sign up 
or

Username is available taken
show password

why


Make sure to remember your password. If you forget it there is no way for StudyStack to send you a reset link. You would need to create a new account.
We do not share your email address with others. It is only used to allow you to reset your password. For details read our Privacy Policy and Terms of Service.


Already a StudyStack user? Log In

Reset Password
Enter the associated with your account, and we'll email you a link to reset your password.
focusNode
Didn't know it?
click below
 
Knew it?
click below
Don't know
Remaining cards (0)
Know
0:00
share
Embed Code - If you would like this activity on your web page, copy the script below and paste it into your web page.

  Normal Size     Small Size show me how

Food Micro Lecture 4

Food Micro Midterm 1

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
Created by: goberoi
 

 



Voices

Use these flashcards to help memorize information. Look at the large card and try to recall what is on the other side. Then click the card to flip it. If you knew the answer, click the green Know box. Otherwise, click the red Don't know box.

When you've placed seven or more cards in the Don't know box, click "retry" to try those cards again.

If you've accidentally put the card in the wrong box, just click on the card to take it out of the box.

You can also use your keyboard to move the cards as follows:

If you are logged in to your account, this website will remember which cards you know and don't know so that they are in the same box the next time you log in.

When you need a break, try one of the other activities listed below the flashcards like Matching, Snowman, or Hungry Bug. Although it may feel like you're playing a game, your brain is still making more connections with the information to help you out.

To see how well you know the information, try the Quiz or Test activity.

Pass complete!

"Know" box contains:
Time elapsed:
Retries:
restart all cards