spoilage - microbial growth

Question 1

Rate these sources of contamination in size: bacteria, fungi, virus, parasites

Answer 1

virus
bacteria
parasites
fungi

Question 2

a suitable environment has:

Answer 2

• resources needed for growth (nutrients)
• physico chemial conditions that do not hinder the organsism

Question 3

GT

Answer 3

time needed to double

Question 4

catabolism

Answer 4

the metabolic route that are involved in the degration of a carbon

Question 5

anabolism

Answer 5

the metabolic routes involved in the biosynthesis of carbon

Question 6

chemo-heterotrophs

Answer 6

they use performed molecules from other organisms as enerhy and carbon source

Question 7

how can we change the nutriens and barier preservation?

Answer 7

• changing product formulation
• by processing (introduce or remove barriers)

Question 8

acid

Answer 8

0 < pH optimal < 5,5 (fungi yeast LAB)

Question 9

neutro

Answer 9

5,5 < pH optimal < 8 (bacteria)

Question 10

alkalo

Answer 10

8 < pH optimal < 112

Question 11

[HA]

Answer 11

concentration undissociated acid

Question 12

what is the difference between fermentation and acidic preservatives

Answer 12

fermentation uses the LAB to produce weak acids that lower the pH and inhibit grwoth
acidic preservative use the addition of acid in order to lower the pH

Question 13

which can enter the cell easily? [HA] or [A-]

Answer 13

Undissociated acids pass the membrane easily –> diassociating in the cell and killing the MO

Question 14

modified atmosphere packaging:

Answer 14

• high CO2
• low O2

Question 15

wateractivity

Answer 15

measure of the ‘ free’ water available in a food product

Question 16

what is the difference between microbicidal and microbiostatic

Answer 16

aims to kill vs prevents to grow