Utah Food Safety Practice Test

A rice and vegetable casserole was baked and then sat on the counter unopened for six hours. Which organism might you suspect could grow and cause illness?

1. Bacillus Cereus

2. Salmonella

3. Escherichia coli

4. Listeria monocytogenes

The correct answer is: Bacillus Cereus

Bacillus cereus is a common organism associated with rice and starchy foods. It produces toxins that can lead to foodborne illness, especially when food is left at room temperature for extended periods. In the scenario presented, the rice and vegetable casserole was left on the counter for six hours, which exceeds the safe time for perishable foods to remain unrefrigerated. This creates an ideal environment for Bacillus cereus to proliferate, as it can survive cooking and can grow in cooked rice that is kept warm or at room temperature. In contrast, while Salmonella, Escherichia coli, and Listeria monocytogenes can also be significant foodborne pathogens, they are typically associated with different types of foods or specific conditions that were not highlighted in this scenario. For example, Salmonella is often linked to raw or undercooked eggs and poultry, E. coli to undercooked ground beef and unpasteurized dairy, and Listeria to ready-to-eat deli meats and unpasteurized cheeses. Thus, Bacillus cereus stands out as the most likely suspect in this situation of a rice-based dish left out for too long.