Question

food surfaces and equipment are not fully cleaned and sanitized until?
they have been placed in heated, soapy water.
they have been treated with heat or chemicals.
they have been allowed to air dry completely.
they have been completely rinsed clean of soap and dirty water.

Explanation:

To fully clean and sanitize food surfaces and equipment, they need to be treated with heat or chemicals (sanitization step). The other options: placing in heated soapy water is cleaning, air drying or rinsing don't sanitize. Sanitization (using heat/chemicals) is the final step to ensure safety.

Answer:

They have been treated with heat or chemicals.