Three Ways To Detect Metal Contamination In Processing Lines

By Melissa Lind, contributing writer

Foreign body contamination in food products often takes a second-seat to bacterial contamination, but foreign bodies can have a significant effect on your company’s bottom line, with metal contamination being one of the guiltiest offenders.

Foreign body contamination — specifically metal fragments — is a major threat to your food production line.  Many of the contaminants are detected in sealed products, indicating that the contamination occurred in-process and wasn’t identified during production or found a final product assessment. Preventing metal fragment contamination in your processing line has a simple solution that is fairly easily deployed.  Modern production lines have improved with high-tech and higher-speed processes. However, these newer systems often use machinery with moving parts that in high stress environments can break, wear, and sheer. This results in small, metal fragment incorporated into final food products.

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An in-process metal detection system can prevent contaminants from reaching the end product, enabling your company to use attractive and engaging packaging, which is oftentimes metallic.  Depending on the likely source of contaminant, metal objects can be detected through a variety of well-known technologies:

• Magnets — physical or electro magnetics can be used to detect ferrous metals and are quite inexpensive.  They work best in dry ingredient lines, but have drawbacks including the lack of ability to detect non-ferrous metal — brass and aluminum — and don’t work well on round contaminants
• X-Ray — these systems are one of the most common types of foreign body detection in food manufacturing and processing.  X-rays can be used to detect most types of metal and other hard-body objects — glass, bone, and high-density plastic.  These systems don’t work as well with very small contaminants, but the technology is well developed, works well in high-production lines, and are moderately priced.
• Metal Detection — there are several ways that metal detection units operate. First, pulse metal detectors work well with large, bulk, raw materials and are used early in the manufacturing line.  Next, ferrous-in-foil systems can detect ferrous metal in foil type packaging. This is spot is particularly tough as many systems for metal detection won’t work through foil.  Finally, balanced-coil systems are most common and can be used in a wide variety of products, both finished and dry.  These systems identify fragments of metal as small as 1 mm, but don’t work with metallic packaging or with salty or wet products.

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There are other choices for metal detection that can be made based on your products and your company’s needs, but in no case can you afford to disregard the effects of metal contamination.  Contamination of any type will can cause significant damage to your brand loyalty, reputation, and ultimately the bottom-line.