Bacillus sp. and Staphylococcus Flashcards Preview

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Flashcards in Bacillus sp. and Staphylococcus Deck (16):

What differentiates B. cereus from B. thuringiensis and B. anthracis?

The toxin each produces is the only difference between them.


What are the 2 types of toxins Bacillus can produce and how are they different from each other?

Emetic and diarrheal. See slide 6 for a chart comparing them.


Does S. aureus cause an infection or an intoxication?



How are the toxins the S. aureus produces named/identified?

Slide 14.


How does S. aureus toxin induce vomiting?

Slide 14.


What kinds of characteristics do the foods associated with contamination by S. aureus have?

Slide 16.


What is noteworthy about the oxygen requirements for Bacillus cereus, that is distinct from other pathogens we discussed this semester?

B. cereus is a strict aerobe


The emetic toxin of B. cereus is also called....



What distinguishes the B. cereus emetic toxin from enterotoxin, in terms of resistance to intrinsic/extrinsic factors?

Cereulide is resistant to heat, pH, proteolysis; see slide 7 for specifics.


What are three reasons that even though B. cereus is frequently found in pasteurized milk, it doesn't cause much illness via this route?

see slide 9; has to do with abundance of the organism, temperatures for toxin production, and defects in product


What are two ways heat processing selects for the growth of Bacillus in foods?

See slide 9; specifically, how does pasteurization affect Bacillus, and why does heat treatment impact its growth in foods such as rice?


What is most noteworthy about S. aureus, in terms of water activity for growth?

It grows at the lowest water activity (low to mid 0.8's) of any pathogen we discussed this semester)


What Staphylococcus aureus toxin type is most associated with foodborne illness?

type A


What is noteworthy about the resistance of Staphylococcus enterotoxins, compared to most enzymes?

Staph enterotoxin is resistant to degradation by proteolytic enzymes and to heat.


What are the five common features of foods that are linked to Staphylococcus aureus illnesses?

See slide 16 for this list; one or more of these are usually found in outbreaks.


When we say "keep hot foods hot, and cold foods cold" in order to prevent foodborne illness, how do we define "hot" and "cold"?

140 degrees and 40 degrees Fahrenheit