Lecture 4: Antimicrobials and Water Activity Flashcards Preview

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Flashcards in Lecture 4: Antimicrobials and Water Activity Deck (6):
1

What are the four kinds of antimicrobial barriers?

See slide 7.

2

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

See slides 9-10.

3

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.

4

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.

5

When are microbes most vulnerable to preservatives and inhibitors?

When they are actively growing (log phase)

6

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.