Final answer:
A food worker should wash their hands for at least 20 seconds, focusing on all parts of the hands, especially under the fingernails, to effectively remove debris and microorganisms.
Step-by-step explanation:
A food worker should scrub their hands for at least 20 seconds during the hand washing process. Proper handwashing technique includes wetting the hands with clean, running water, applying soap, and then rubbing the soap all over the hands, which should include commonly missed areas such as the thumbs, wrists, areas between the fingers, and under the fingernails. Using a nail brush can help remove debris and microorganisms. To time the duration for scrubbing effectively, humming the "Happy Birthday" song from beginning to end twice can serve as a practical timer. This process is critical in preventing the spread of foodborne diseases and pathogens.