Food Manager Practice Exam

What pH range do bacteria prefer for growth?

1. 2.0 - 4.5

2. 4.6 - 7.5

3. 7.6 - 9.0

4. 9.1 - 12.0

The correct answer is: 4.6 - 7.5

Bacteria generally thrive in a moderately acidic to neutral pH range, which is typically between 4.6 and 7.5. This range is ideal for many pathogenic and spoilage bacteria, as it supports their metabolic processes and growth. Most foodborne bacteria, such as Salmonella and Escherichia coli, prefer environments that are not too acidic nor too alkaline, as extreme pH levels can inhibit their growth and activity. By maintaining food within this pH range, food safety practices can help prevent bacterial growth that may lead to foodborne illnesses. The other options listed reflect pH levels that are either too acidic or too alkaline for most bacteria to thrive. For example, very low pH levels, such as those in the 2.0 to 4.5 range, can be detrimental to bacterial growth and are more likely to inhibit many microorganisms. Similarly, higher pH levels, as seen in the 7.6 to 9.0 and 9.1 to 12.0 ranges, may support growth of certain alkaliphilic bacteria, but they are generally not the preferred environments for the majority of pathogenic bacteria found in food.