2.2: describe how and when cleaning agents are used.

Cleaning agents are substances (usually liquids, powders, sprays, or granules) used to remove dirt, including dust, stains, bad smells, and clutter on surfaces. Purposes of cleaning agents include health, beauty, removing offensive odor, and avoiding the spread of dirt and contaminants to oneself and others. Some cleaning agents can kill bacteria and clean at the same time.

Cleaning agents should be used when trying to prevent infection and when complying to regulations. that is if they are medical cleaning agents. but household cleaning agents also are used to clean and disinfect objects such as infant toys, clothes, food utensils and cutlery, floors and tiles, glass, etc. 
examples of cleaning agents are alcohol, dish soap or laundry detergent, and bleach, and hydrogen peroxide.

-hope this helps

Think it's rice because in many countries rice is the main food so it can be traditionally served all at once.