Which of the following is NOT a method of food contamination?

Thermal is not recognized as a method of food contamination because it primarily refers to temperature-related processes, such as cooking, chilling, or holding food. These processes are essential for ensuring food safety by preventing the growth of harmful microorganisms rather than causing contamination.

On the other hand, biological, chemical, and physical contamination are well-defined methods. Biological contamination involves harmful microorganisms such as bacteria, viruses, and parasites that can contaminate food. Chemical contamination occurs when harmful substances, such as pesticides, cleaning agents, or additives, inadvertently mix with food. Physical contamination refers to foreign objects, like hair, glass, or metal shavings, getting into food products. Thus, thermal does not fit into the same category as the others in terms of food contamination risks.