Spoilage Flashcards
(44 cards)
When does spoilages start to become noticable
10^7 cells per gram
Generation time
time needed for the population to double
Which enzymes are present in aerobic MO’s that break down ROS?
superoxide dismutase and catalase
Obligate aerobe
Needs O2
Microaerophile
requires 2-0% O2, damaged by 20%
Facultative anaerobic
does not require O2, but grows better with it
aerotolerant anaerobe
grows equally well with or without O2
obligate anaerobe
Dies with O2 present
A lower pH gives a higher or lower redox potential?
higher Eh due to many H+
What happens when meat is vacuum packed?
There is residual respiration which consumes the O2 and produces CO2, this inhibits some MO’s.
Why does meat become pink/grey in a vacuum?
Because myoglobin can not bind to O2 anymore
xerophilic
grows on dry foods
osmophilic
grow in high concentrations of unionized compounds (sugar)
halotolerant
Grows in salted procts
Halophilic
Requires high levels of salt
What do microbicidal preservatives do?
Kill the MO’s
What do microbistatic preservatives do?
Prevent the growth of MO’s
Why would you add sulphite to a food
To acidify the product
Why would you add nitrite to a product?
To target clostridium and for the colour of meat.
psychrophile
Between -5 and -20 degrees
Psychrotolerant
Between -5 and -35 degrees
mesophile
Between 4 -47 degrees
Thermophile
Between 40-90 degrees
Thermotolerant
Will survive mild pasteurization
