Chapter 30 Flashcards
Microorganisms in food
Food poisoning caused from the ingestion of bacteria that are toxin causing. The bacteria release toxins while in the digestive tract. Can take 12-36 hours for onset.
Infection
Food poisoning resulting from the ingestion of food that contains exotoxins (released from bacteria). Quicker onset of symptoms (4-6 hours)
Intoxication
Who am I?
I cause food-born intoxication via the release of an enterotoxin, I am heat-stable, I grow on the skin and thrive in salty conditions where other bacteria might not. 4-6 hour onset.
Staphylococcus aureus (aw-ree-us)
Who am I?
I cause foodborne illness via intoxication; I cause a deadly paralytic disease when my neurotoxin is ingested. I am an anaerobic, endospore-forming, G+ rod. Just a few mg are enough to kill a city! pH above 4.5 can cause the endospores to germinate. Heat-labile. 12-36 hours onset
Clostridium botulinum
True or False: The bacteria that cause food spoilage are not the same as the ones that cause food poisoning.
True
Some foods have naturally occurring antimicrobial chemicals. Eggs have _____________, cranberries have ____________.
Lysozymes, benzoic acid
Extremely harmful/toxic infection adjective
Virulent
Fomites
Objects or materials likely to carry infection (door knobs, clothes, utensils)
Define mycolic acid in Mycobacterium
Located in the outer membrane; similar to gram-neg bacteria but with mycolic acid instead of LPS
Non-toxic disinfectant, safe on skin and mucous membranes
Antiseptic
Disinfectant level of alcohols with contact time less than a minute
Low-level
Disinfectant level of phenol and iodophors with contact time over a minute
Intermediate-level
Contact time
Length of time a chemical needs to be in contact with a microorganism in order to kill it
Disinfectant level of hydrogen peroxide and sodium hypochlorite with contact time 12 and 30 mins corrode metals
High-level
Most of the following are resistant to general purpose disinfectants:
Endospores, non-enveloped viruses, mycobacteria
Microbial growth is inhibited by:
Altering cell wall structure, damaging cytoplasmic membrane or denaturing proteins (alcohols+heavy metals)
Minimum inhibitory concentration
The first tube in a series of serial dilutions that shows no growth —used to determine the minimum concentration of chemicals to inhibit bacterial cells
TSA
Trypticase soy agar
_______ bacteria ferment the main sugar in milk, lactose, producing _____. pH is lowered as a result.
Lactic acid
Exotoxin that causes intestinal disturbance such as diarrhea and vomiting
enterotoxin
Exotoxin that cause damage to the nervous system, causing symptoms such as paralysis
neurotoxin
Exotoxins that cause damage to a variety of different cell types such as disrupting general cellular mechanisms or by lysing the cell
cytotoxin
Heat-sensitive
Heat-labile
