Final answer:
The label should include employee initials and indicate that the food is not for sale.
Step-by-step explanation:
The label on the 'do not use' food in the walk-in should include employee initials. This helps to identify who labeled the food and indicates that they are aware of the situation. Additionally, the label should indicate that the food is 'not for sale' to prevent anyone from inadvertently using it. Temperature records and expiry dates may be helpful for tracking the food's history, but they are not necessary for the label.