FINAL EXAM P4

Question 1

prions

Answer 1

essentially infectious proteins
don’t have a nucleus
every brain has them, but we do not know their function
are shape shifters

Question 2

altered prions

Answer 2

have destructive potential
can trigger others into an irreversible chain reaction
as this spreads, holes appear and death is inevitable
fatal familial insomnia

Question 3

mad cow diesase

Answer 3

in England, they took waste products from sheep and fed it to the cow, transmitting the disease. by the time they realized, people had already consumed the beef, leading to the variant C J disease. humans that donated blood further transmitted the disease

Question 4

Creutzfeldt-Jakob disease

Answer 4

genetic inherited form of cow disease

variant is what people get from consuming beef

Question 5

kuru

Answer 5

has only been found in pacific populations, transmitted because they eat the elderly when they die

Question 6

perishable food

Answer 6

fruits, veggies, meat, and fish

Question 7

semi-perishable food

Answer 7

can be stored for weeks or months, doesn’t necessarily need refridgeration

Question 8

stable or non perishable food

Answer 8

can be put on a shelf at room temp for months or years without worrying about microbes

Question 9

microbial growth

Answer 9

can lead to spoilage or food preservation / flavor change via fermentation

Question 10

effect of storage temperature

Answer 10

way to inhibit microbial growth
refrigerator is about 4C and dramatically slows growth
some organisms are psychrophilic and are still able to grow
freezer is about -20C and completely stops growth

Question 11

acidity

Answer 11

aka pickling
often the result of fermentation of the food
done with vinegar (acetic acid)
are not harmful

Question 12

decreased water activity

Answer 12

lowers or makes water less available by adding high concentrations of solute (salt or sugar)
drying also removes water

Question 13

chemical preservatives

Answer 13

can be added and non toxic to humans

broken down in the stomach, so you’re safe

Question 14

canning

Answer 14

form of sterilization

kills every microbial cell so food can be preserved for storage. heating time is required to kill bacterial spores

Question 15

what happens if you don’t kill everything in the can

Answer 15

normal cans should be slightly bowed inwards
if the lid pops up and down, it was not properly prepared.
with significant growth, the microbes produce gas and buckle the can out

Question 16

irradiation

Answer 16

the food is passed by a source of radiation. it is not radioactive, its energy simply goes through the food and peels the bacteria.
does not sterilize the food
decreases viable counts

Question 17

pasteurization

Answer 17

heating at a moderate temperature for a short time
goal is to kill microbes without destroying food quality
decreases viable count and does not sterilize

Question 18

fermented food

Answer 18

increases shelf life
sugars are converted to alcohol or acid (vinegar)
antibiotics are some fermentation products that are inhibitory to other organisms
produces flavor in cheese, buttermilk, yogurt, and alcoholic beverages, as well as sausages/pepperoni, cabbage (sauerkraut), cucumbers (pickles), and soy beans (soy sauce)

Question 19

food poisoning

Answer 19

aka food intoxication
food contains a microbe, but the microbe grows in the food and produces a toxin that you eat. often “self-limiting”, you have symptoms for a short period of time and they go away.

Question 20

self limiting

Answer 20

the amount of time for the toxin to move through your body until you feel better

Question 21

food infection

Answer 21

infection is when the microbe has to grow inside the host
you eat the microbes on the food and it grows inside you
doesn’t take up long term residence
may or may not be self limiting
can last for weeks or months

Question 22

endotoxin

Answer 22

lipopolysaccharide that is generally not a food poisoning toxin

Question 23

exotoxin

Answer 23

proteins released by the microbe

Question 24

enterotoxins

Answer 24

only affect the GI tract