Cross-contamination is the process whereby harmful bacteria from food spreads to other foods, surfaces, hands, or equipment. Even a trace of food on a utensil, cookware, or surface can cause an allergic reaction or food-borne illness. Contaminants are invisible to the human eye and can be served unknowingly. Therefore, there is a need for a reliable way to detect if a food product purchased by a consumer is fit for consumption. ServeSafe protects customers from food-borne illness and potentially life-threatening allergic reactions and upholds a restaurant’s legal duty of care to serve food that is safe for consumption and protect their patrons from undue harm. It uses surface plasmon resonance (SPR) to monitor changes in the refractive index of a sample and detect contaminants.