Physical foreign materials, like rocks or metal, must be checked for in food production.

Physical Foreign Materials

What are Physical Foreign Materials?

A physical foreign material is anything that does not belong in the food product. These substances can be classified as food safety hazards or quality and consumer complaint issues.1

Some examples of physical foreign materials are:

  • Stones
  • Metals
  • Brittle plastics
  • Wood

Establishing a physical foreign material control program is necessary for food safety compliance. The majority of consumer complaints received by food manufacturers and retailers relate to foreign physical materials in foods. Having a system in place to monitor the process from raw materials to finished goods will reduce the risk for bakeries.


Food consumption patterns have migrated from locally sourcing to long-distance transportation of products. In the early 1920s, a stem found in a can of green beans would have been tossed aside without any thought to food safety.[2]  Fast-forward to the mechanization of food, and foreign materials such as glass, wood, metal, and rubber pose greater risks to consumers.

As a result, the FDA established Good Manufacturing Practices to deal with physical foreign materials.

Section 110.80(b)(8) of the GMP states:2

Effective measures shall be taken to protect against the inclusion of metal or other extraneous materials in food. Compliance with this requirement may be accomplished by using sieves, traps, magnets, electronic metal detectors, or other effective means.

The United States Department of Agriculture Food Safety and Inspection Service defines foreign materials as non-animal objects such as metal, plastic, rubber, glass, wood, steel, or lead shot.2

Regulatory compliance

Physical foreign materials in food may pose a health or safety risk to consumers. Requirements for regulating physical foreign materials and Good Manufacturing Practices are outlined under  FDA 21 CFR Part 117 Sec. 117.130 Hazard analysis.3  They are seen as a lower risk and can be controlled through metal detectors and supplier approval programs as part of a robust Hazard Analysis and Critical Control Points (HACCP) plan.

Application - how...

To access the rest of this page, you must be a member of the American Society of Baking.