The food worker should use the following method to safely thaw the large frozen ham:
1. Refrigerator thawing: This is the safest method for thawing a large frozen ham. Place the ham in its original packaging or in a leak-proof plastic bag and put it on a tray or in a shallow pan to catch any potential drips. Then, place the ham in the refrigerator and allow it to thaw slowly over time. It is recommended to allow approximately 24 hours of thawing time for every 4-5 pounds of ham. This method ensures that the ham stays at a safe temperature throughout the thawing process.
It is important to note that using cold water thawing or microwave thawing methods may not be suitable for a large ham, as they may not allow for even and thorough thawing, increasing the risk of bacterial growth. Therefore, refrigerator thawing is the recommended method for safely thawing a large frozen ham.