Which of the following is a simple way food can be contaminated?

Food can become contaminated through various means, and scratching your scalp is a relevant example. This action can transfer bacteria and pathogens from your scalp to your hands. If those hands then touch food or food preparation surfaces without proper washing, contamination can occur.

Recognizing the pathways of contamination is crucial in food safety practices. It illustrates the importance of personal hygiene in food preparation environments. Maintaining clean hands and avoiding touching hair or face while handling food is essential for preventing potential foodborne illnesses.

In contrast, adding new ingredients, refrigerating leftovers, and cooking food thoroughly are practices aimed at safe food handling, reducing the risk of contamination rather than contributing to it.