Final answer:
To safely cook a large batch of tuna casserole, the worker should bake it in an oven and check that it reaches the safe internal temperature of 165°F using a food thermometer, as per the given reference, 'Figure 4.7.7'.
Step-by-step explanation:
To safely cook a large batch of tuna casserole, a food worker should use an oven and bake the casserole at a consistent temperature. It is crucial to ensure that the casserole is cooked evenly throughout. Per safety guidelines, all parts of the casserole should reach an internal temperature that is high enough to kill any potentially harmful bacteria.
The use of a food thermometer is essential in this process. According to the image reference, 'Figure 4.7.7: To be on the safe side, use a thermometer to make sure food reaches a high enough temperature to kill any bacteria it contains', it is clear that monitoring the temperature is a key step in ensuring the casserole is safe to eat. For casseroles, the recommended safe temperature is typically 165°F (74°C), measured at the center of the dish.