Final answer:
Dunnage racks are used for safe food storage, and the statement that they can be empty is generally false as they usually need to be in use to maintain proper food safety and sanitation.
Step-by-step explanation:
The question pertains to dunnage racks, which are typically used in storage or warehousing environments, including walk-in refrigerators, to keep food off the floor and to comply with health regulations. Dunnage racks must generally be kept clean and not empty to ensure proper air circulation and to prevent contamination of food products. Therefore, the statement 'We can have empty dunnage racks' would be false, since dunnage racks are usually required to be in use when products are being stored to maintain a sanitary environment. It's important for students in food safety or health classes to understand proper storage protocols to ensure food safety and to comply with local health department regulations.