What is a common sign of food spoilage?

A common sign of food spoilage includes off smells, unusual textures, or changes in color. When food is beginning to spoil, it often develops a sour or unpleasant aroma, signaling the presence of bacteria or decay. Textures can change as well, with food becoming slimy, mushy, or otherwise unappetizing, indicating that it is no longer safe to consume. Additionally, changes in color can suggest spoilage; for example, meat may turn a dull gray or green, and fruits and vegetables may appear brown or wilting.

The other options do not signify spoilage. Bright colors and strong smells might imply freshness in some contexts, depending on the food. A firm texture and pleasant odor usually indicate that food is still safe to eat. Unchanged packaging suggests that the food inside has not been tampered with and may still be safe, but it does not guarantee that the food itself is not spoiled. Therefore, being aware of the signs of spoilage is crucial for food safety.