Extraneous Matter Examination

Extraneous materials are any foreign substances in foods associated with objectionable conditions or practices in production, storage, or distribution of foods. Extraneous materials can be separated from food products by particle size, sedimentation, and affinity for oleophilic solutions. Once isolated, extraneous materials can be examined microscopically. This laboratory exercise utilizes techniques to isolate the extraneous matter from various foods: cottage cheese, jam, infant food, potato chips, and citrus juice. The description of the procedures for these foods is based on AOAC International methods, but the quantities are reduced to half.