Answer - A -Detergent is considered a chemical contaminant. While detergent is often used in dishwashers and at the pot washing station, when it comes to consuming food, having a chemical detergent present in the food is certainly an example of a chemical hazard. Glycerol, also known as glycerine or propanetriol, is a non-toxic artificial sweetener, so it is not a contaminant. Unwashed vegetables may have residual pesticides on them, but they are more likely to harbor biological contaminants such as disease.