Case Study: Foreign Material in Food

Foreign material in food can be a concern; a physical contaminant such as glass, metal, or wood can cause injuries to consumers. Contaminants can be introduced to a food or beverage product at any point during production or distribution. This can be due to issues with equipment or inadequate handling by people. Food and beverage facilities usually have foreign matter control programs to locate contaminants before the product reaches the client, but sometimes those programs fail.

THE PROBLEM:

A national restaurant chain received a complaint from a customer about an unidentified green matter found on a piece of bread. To adequately address the complaint, the restaurant needed to identify the green matter and determine if their product had been tampered with or if the contamination issue was the result of problems with preparation, packaging, or processing.

THE ANALYSES:

The foreign green material was concentrated locally in the bread interior with only a small portion exposed at the surface of the bread. Examination of the foreign green material was conducted using a polarized light microscope (PLM), scanning electron microscope (SEM) coupled with energy dispersive x-ray spectrometry, and a micro-Fourier infrared spectrophotometer (micro-FTIR).

THE OUTCOME:

Data from the SEM/EDS analysis showed us that the foreign green material is mainly composed of carbon. It appears to be a stain or dye locally concentrated in the interior bread layer indicating that contamination occurred during mixing and prior to baking. Trace quantities of dyes are often all that are necessary to impart color to a variety of products. Based on this information, the restaurant was able to successfully trace the problem back to the baker that supplied their bread. In this situation, the food defect did not present a health hazard for consumers.