Final answer:
To sanitize in a three-compartment sink without chemicals, immerse items for 2 minutes at 77°C (171°F), ensuring sufficient heat to kill microbes for public health safety.
Step-by-step explanation:
When sanitizing items in a three-compartment sink, one method aside from using a chemical sanitizing solution is to immerse them for 2 minutes in water that is at least 77°C (171°F). This method ensures sufficient heat transfer to kill most microbes and achieves the required sanitization level for the safety of public health. The dropped temperature scenario of 38°C (100°F) is not sufficiently hot for proper sanitization. Sanitization aims to reduce the microbial load on items to safe levels and can be achieved through the application of antimicrobial chemicals or through heat, which is a critical component in killing bacteria and ensuring that items are safe to use, especially in food service and healthcare settings.