Which item is necessary to prevent cross-contamination while building sandwiches?

Using a clean sandwich liner is essential for preventing cross-contamination while building sandwiches. The sandwich liner serves as a barrier between the food and any surfaces that may have come into contact with allergens or contaminants. This ensures that ingredients remain uncontaminated and safe for consumption.

While a separate cutting knife, plastic wrap, and a colored cutting board can also play roles in maintaining food safety, they do not serve as direct barriers between the food and potential contaminants in the same way that a clean sandwich liner does. The liner directly protects the food being assembled, helping to mitigate risks associated with cross-contact, especially in busy environments like a kitchen where multiple food items are handled simultaneously.