What corrective action was taken by the chef after finding beef stew at 120F?

Reheating the stew to 165°F for 15 seconds is the appropriate corrective action because it ensures that the stew reaches a safe temperature to kill any harmful bacteria that may have developed while it was held at an unsafe temperature. The temperature of 120°F falls within the danger zone (41°F to 135°F), where bacteria can multiply rapidly, increasing the risk of foodborne illness if the food is consumed. By reheating the stew to at least 165°F, the chef eliminates potential pathogens and ensures that the food is safe for consumption.

In contrast, discarding the stew would result in food waste without addressing the safety concerns effectively, as the goal is to salvage the product when possible. Cooling the stew to below 41°F is not a suitable option after it has already been held at 120°F, as it may still harbor harmful bacteria at that temperature. Holding the stew at a lower temperature would not rectify the unsafe condition, as it would remain in the danger zone and continue to pose a risk of foodborne illness. Thus, reheating is the correct approach to ensure safety while preserving the food.