Lecture 4: Antimicrobials and Water Activity Flashcards Preview

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Flashcards in Lecture 4: Antimicrobials and Water Activity Deck (6):

What are the four kinds of antimicrobial barriers?

See slide 7.


Allicin and isothiocyanates are examples of what kind of microbial inhibitor?

See slides 9-10.


Improper cooling/washing of a warm cantaloupe with cold water, lowering the pressure inside and pulling microbes in, is a failure of what antimicrobial barrier?

Biological Structure. Think about the eggshell example from class.

Fun fact: This was a potential explanation for the Listeria monocytogenes cantaloupe outbreak of October 2011. Several other methods of contamination were also found but the above explanation was also considered.


In what ways can eggs inhibit gram positive and gram negative bacteria?

See slide 11.
Example: lysozyme can digest a G+ cell wall an EDTA can chelate the outer membrane of a G- exposing the cell wall to lysozyme.


When are microbes most vulnerable to preservatives and inhibitors?

When they are actively growing (log phase)


What are some problems we face when trying to incorporate essential oils into foods as an inhibitor?

Reference slides 12-13.
Incorporating hydrophobic oils into hydrophilic substances. Flavor imparted my the oil may be undesirable.