Final answer:
The proper discard date for a dish with combined precooked items is the earliest discard date of all the included ingredients. Rapid cooling of large quantities of homemade soup is important to prevent bacterial growth.
Step-by-step explanation:
When making a dish such as soup that includes multiple precooked items, the proper discard date to mark on the food is based on the earliest discard date of all the included ingredients. Because foodborne disease agents can survive or grow at varying rates in different food items, taking the precaution of using the earliest discard date helps ensure the safety of the dish.
Rapidly cooling large quantities of homemade soup before storage, such as by placing the pot in an ice water bath, is crucial to prevent the growth of bacteria. Microorganisms proliferate rapidly between temperatures of 4 and 60 degrees C (40 and 140 degrees F), a range known as the 'danger zone.' By cooling the soup rapidly, it passes through the danger zone quickly, minimizing the time bacteria have to multiply.
Practices like using a thermometer to check that food has reached an internal temperature of at least 74 degrees C (165 degrees F) and properly rotating food in storage are additional measures for preventing foodborne illnesses and ensuring food safety.