Control of Metal Contamination in Raw Materials

An important part of any Hazard Analysis and Critical Control Point (HACCP) based quality control program in the food industry is the use of a metal detection system. The inspection of raw materials for contamination early in the process is highly recommended. However, the wet characteristics of some materials present a challenge for traditional metal detectors due to the product effect.

Product effect occurs when the product’s own characteristics inhibit the metal detector’s ability to identify specific contaminants.  Traditionally, the solution to overcoming product effect was to reduce the sensitivity of the metal detector. However, this significantly increases the risk of metal contaminants going undetected, and ultimately increases the chances of metal contaminated products reaching retailers' shelves and end consumers.

The most sensitive metal detectors on the market operate at more than one frequency simultaneously and are known as multi-simultaneous frequency (MSF) detectors. Combined with advanced features such as product signal suppression (PSS), they address the problem of product effect in a new and innovative manner. This enables the metal detection system to detect more contaminants and overcome the product effect without increasing product waste through false rejects.

In some cases, detection sensitivity for metallic contaminants can be increased by up to 50% (based on ball diameter). This is in comparison with conventional metal detection systems when inspecting wet products or those with high salt content, variable temperature, or those packed in metallized film. The use of this technology enables food processors to remove the product signal to allow the detection of smaller metal contaminants. This protects the reputation of the brand and the welfare of consumers but can also strengthen a company’s competitive edge.

Download this case study to discover how Zentis GmbH & Co, a leading player in the processing of fruits and other natural raw materials, put their trust in advanced metal detection systems to maintain the high quality of its fruit preparation and the resulting safety for consumers