Bacillus cereus: The Invisible Threat Rice can harbor bacteria, and danger isn’t always visible. The main culprit is Bacillus cereus, a bacterium that survives cooking. When rice is cooked, spores of this bacteria can endure the heat. If the rice sits out too long before refrigeration—or cools too slowly—these spores multiply quickly. Even worse, the toxins they produce aren’t destroyed by reheating....