Chemical contamination occurs when toxic substances are introduced into food, often through improper storage or the use of non-food-grade materials. A classic and frequently tested example in the ServSafe Manager curriculum is the storage ofacidic food or beverages in copper containers. Orange juice is highly acidic. When an acidic liquid comes into contact with copper, it causes a chemical reaction known as "leaching," where copper ions dissolve into the liquid. If consumed, this can lead to heavy metal poisoning, resulting in symptoms like nausea, vomiting, and diarrhea, often occurring within minutes.

The FDA Food Code strictly prohibits the use of "reactive metals"—including copper, brass, lead, pewter, and galvanized zinc—for the storage or preparation of acidic foods. Other examples include storing tomato sauce in a copper pot or lemonade in a galvanized bucket. In contrast, glass, food-grade plastic, and most modern china are considered "non-reactive" and safe for acidic items. Managers must ensure that all equipment used in the kitchen is labeled as "food-grade" or bears the NSF/ANSI certification. This also extends to the use of chemicals like cleaners, sanitizers, and polishes, which must be stored away from food-prep areas in their original containers or clearly labeled secondary containers. This specific hazard (toxic metal leaching) highlights the importance of understanding the chemical properties of both the food and the equipment being used. By ensuring that acidic foods never touch reactive metals, a manager eliminates a significant and preventable chemical hazard from the operation.