How do bacteria primarily grow in food?

Bacteria primarily grow in food through warmth, moisture, and nutrients present in the food. These conditions create an ideal environment for bacteria to thrive. Most pathogenic bacteria flourish in the temperature range known as the "danger zone" (between 41°F and 135°F), where they can multiply rapidly. Additionally, moisture is essential for bacterial growth, as most bacteria require a certain level of water activity in their environment to survive and reproduce. Nutrients found in food, such as proteins and carbohydrates, serve as energy sources for bacterial metabolism.

The other options do not provide the necessary conditions for bacterial growth. Exposure to air and light can actually inhibit the growth of some bacteria and may not contribute to their proliferation in food. Freezing food typically slows down or stops bacterial growth rather than promoting it, as low temperatures render the bacteria inactive. Furthermore, bacteria can grow in both processed and unprocessed foods; it is not limited to processed foods, which are often perceived as having preservatives that can inhibit bacterial growth.