PRELAB 1: Intrinsinc factors pH Flashcards
what causes changes in pH in food
microbes
- Enzymes
- Nutrition
Microbes grow best in what pH
neutral or weakly alkaline
6.8-7.5
pH range for molds and yeasts
molds - 1.5-11.0
yeasts: 1.5 8.5
Other environmental factors affecting pH
temperature
salt
age
types of acids
buffering capacity
how can temp affect pH
the higher the temperature the lower the pH or acidic
direct relations
how can salt affect pH
it can broaden the pH or narrow it down when concentration exceeds optimal level
How can age affect pH
young cells of food are more susceptible to microorganisms
how can buffering capacity affect the pH
meat can resist the pH, it has has high buffering capacity
No known pathogen grows below a pH of ____
give an example
4.6
Clostridium botulinum grows at a pH of 7 but is inhibited at 4.6
pH 6-7
meat, milk, corn, vegetables, and eggs
3.5
citrus frutis, pickles, and kiwi
- able to grow in an
acidic environment.
Extremophiles
- able to grow in a super
acidic environment with __ pH
Acidophiles
<2
_______ a microbe that causes ______ It is very sensitive when it comes to pH. It live in a ______ environment with a pH range of _____ and is sensitive to _______
Vibrio cholerae
cholera infection
alkaline
6.8-7.5
acidic conditions
Most bacteria are killed in a strong acid and alkaline environment except
Mycobacterium sp.
