Cross contamination as defined in culinary terms refers to two or more types of raw food coming in contact with one another. All foods contain different types of bacteria, and when those different types of bacteria make contact with one another, they can cause food poisoning. One example would be cutting raw chicken on the same board you cut fish on without sanitizing between tasks. Cross contamination could also refer to chemical or particle exposure to food. If bleach, soap or other chemicals end up in the food, it can make someone very sick. If glass or other fragments end up in the food, it can injure a person. For more information on food safety, visit http://www.servsafe.com.