Which of the following is a sign that food has been contaminated by bacteria?

Food contamination by bacteria can manifest through various signs that indicate spoilage or potential health risks. The presence of a slimy texture suggests the growth of bacteria or other microbes, which can occur when food is improperly stored or has been left out for too long. A strong odor is another common indicator, as decomposition processes produce gases and compounds that generate unpleasant smells. Additionally, a change in color can signify that the food is no longer safe to eat; for example, meat may appear green or gray as it ages due to bacterial activity. Each of these signs is a warning that the food may be contaminated, making it essential for consumers to be vigilant. Since all these signs can indicate different aspects of bacterial contamination, the collective recognition of them reflects a comprehensive understanding of food safety issues.