Which is an example of chemical contamination?

• A. Acidic action of foods with metal-lined containers
• B. Metal curls from a worn-out can opener that fell into the food when the can is being opened
• C. Development of an off-flavor due to uncontrolled enzyme reaction
• D. Anisakis contamination from fish

Answer: (A)

Chemical contamination happens when a chemical substance enters food, altering safety or composition. Acidic foods stored in metal-lined containers can cause the lining to corrode and metals to leach into the food. This is a chemical change driven by a reaction between the packaging and the food, introducing contaminants that weren’t originally present.

The other scenarios involve different types of issues. A metal curl from a worn can opener is a physical contaminant—the presence of a foreign object rather than a chemical substance entering the food. Off-flavors from uncontrolled enzyme reactions are a spoilage process caused by enzymes already in the food, not contamination by an external chemical. Anisakis contamination from fish is a biological contaminant, a parasite rather than a chemical substance.