Which of the following is an extrinsic factor influencing microbial survival in foods?

• A. pH
• B. Water activity
• C. Temperature
• D. Microbial community

Answer: (C)

Temperature is an extrinsic factor because it describes the storage and processing conditions outside the food that affect whether microbes survive. Extrinsic factors are environmental conditions imposed on the food, such as how it’s stored (refrigerated, heated, or kept at room temperature) and how that environment changes over time. Intrinsic factors, like pH and water activity, are properties built into the food itself that influence microbial survival regardless of external conditions. The microbial community refers to which organisms are present and how they interact, which affects survival but isn’t an external environmental parameter in the same sense. Temperature shapes microbial enzyme activity, membrane stability, and stress responses, so it directly governs survival under different storage conditions.