Extrinsic Factors chpter 4

Question 1

What is the difference between extrinsic and intrinsic factors?

Answer 1

Extrinsic factors are factors that can be controlled without changing the food. While intrinsic factors often change the food.

Question 2

What are the two main extrinsic factors?

Answer 2

Temperature and gaseous environment

Question 3

What is the danger zone?

Answer 3

4.4-60C Most microorganisms grow in this range.

Question 4

Minimum growth Temp?

Answer 4

Lowest temp that an organism will grow. SLow growth to no growth. Just cell maintenance.

Question 5

Optimum growth temp?

Answer 5

Temp at which growing fastest.

Question 6

Maximum growth temp?

Answer 6

Temp in whcih cells cannot make any more enzymes, start to die.

Question 7

Kill all viable cells at what temp?

Answer 7

80C

Question 8

Kill all cells at what temp?

Answer 8

Using pressure as well. 100C kills all growth.

at 121C SPORES KILLED.

Question 9

What microorganisms can be survive below 4C?

Answer 9

Listeria, C. botolinum, and yersina entercolitica

Parasites (destroy by below -20C). Viruses are fine.

Question 10

What is used to store bacteria?

Answer 10

Glycerol, it prevents crystalization so we cna store bacteria.

Question 11

Psychrophile

Answer 11

<20C cold lovers. Vibrio

Question 12

Psychrotrophs

Answer 12

30C found in fridge.

Question 13

Mesophiles

Answer 13

> 35C potimal. 7-10C min and 40-60C max

Question 14

thermodurics

Answer 14

Endospore forming survives but do not grow at temp> 60C

Question 15

thermophiles

Answer 15

optimal > 45C SPORES or up till 80C

Question 16

What is the difference between endospores and fungi spores

Answer 16

Endospores from bacteria are heat resistant to heat, drying, and disinfecting chemicals.
While fungi spores are NOT heat resistant.

Question 17

Gaseous environment:

Describe what bacteria is found in aerobic conditions

Answer 17

Gram -, non-spore forming, rods (speudomonaus), oxidateive and breakdown of fats and proteins. odor found at 10^6- 10^7 CFU/g of meat. Gives off CO2.

Question 18

Anarobic conditions

Answer 18

gram +, spore forming, LAB, fermetnave and converts sugar to LA and acetic acid. spoilage is detectable after max population reached.
Low redox potentials. Souring occurs.

Question 19

What is a facultative anarobe

Answer 19

It can survive in both oxygen and no oxygen conditions.

Question 20

aerotolerant anarobe

Answer 20

Survives in the presence of oxygen but still does anarobic metabolism.