What is a common sign of food contamination?

Unpleasant smells or discolorations are clear indicators of food contamination. When food becomes contaminated, it often undergoes physical or chemical changes that can result in off-odors or changes in color. These signs suggest the presence of spoilage or the growth of harmful microorganisms, which can pose a health risk if consumed. Recognizing these signs is critical for food safety, as they can help prevent foodborne illnesses.

In contrast, other options do not necessarily indicate contamination. Bright colors of the food can be completely normal, as many fruits and vegetables are naturally vibrant without being harmful. Food being packaged tightly is a common practice to preserve freshness and prevent contamination, rather than an indication of it. Lastly, food remaining at room temperature is concerning for safety but does not alone serve as a direct sign of contamination unless coupled with other indicators like smell or appearance. Thus, focusing on detection methods like smell and visual cues is fundamental in food safety practices.