Question

Most spoilage bacteria grow at:

• A. neutral pH
• B. acidic pH
• C. alkaline pH
• D. any pH.

Answer 1

The correct option is A

neutral pH

The correct option is A.

Explanation of the correct option:

1. For spoilage microorganisms, a neutral pH is ideal.
2. Most spoilage bacteria exist at neutral pH since germs thrive in this range, but in this case, many bacteria exist in the range of 5-8 pH and perform well there.
3. The bacterial cell membrane can also be damaged by high acidity and high alkalinity.

Explanation of the incorrect options:

Option B:

1. There is a pH where bacteria function best. High levels of acidity or alkalinity will damage proteins and enzymes as well as the cell membrane, effectively slowing down metabolism.
2. Therefore, microorganisms that cause spoiling thrive at neutral pH.

Option C:

1. While most bacteria are inhibited at a pH below 4, yeast and molds may tolerate lower pH levels, microorganisms typically grow at a neutral pH of between 6.6 and 7.5.

Option D:

1. Moderate pH variations affect how amino-acid functional groups are ionized and how hydrogen bonds are formed.
2. These alterations in the molecule's folding then encourage denaturation and destructive activity. The pH that is best for an organism's growth is known as the optimum growth pH.

Final answer: Spoilage bacteria grow at neutral pH.