How to Prevent Foreign Material Contamination in Food

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27 Oct, 2025

How Screening for Foreign Material Contaminants Supports Compliance in the Food Industry

Preventing the introduction of foreign materials in food production is essential for brand protection, consumer safety and compliance with industry requirements. The presence of any foreign object in food can lead to serious consequences, including long-lasting brand damage, financial losses, and harm to consumers.

Implementing metal detection and x-ray inspection systems as part of a comprehensive foreign material control program is critical in the fight against physical contamination. These systems enable manufacturers to inspect each product for quality and safety, which helps to protect their business and support compliance with food safety standards.

Effective prevention of foreign substances in food requires more than just installing inspection equipment. To maximize system benefits and protect your investment, food manufacturers must understand the potential contamination risks, select the appropriate technologies, and strategically position these systems along the production line.

Continue reading as contamination detection experts Ben Pimblett and Mike Pipe share insights on preventing physical contamination in food, the advantages of different technologies, and how to choose the most suitable contamination detection solution—metal detection, x-ray inspection, or a combination of both.

Meet Our Experts

Mike Pipe, Head of Product Inspection Division UK and Ireland

Mike has more than 17 years of experience at METTLER TOLEDO. He has worked in both commercial and technical roles to support food and pharmaceutical manufacturers. His work helps these businesses comply with regulations, improve productivity, and drive consumer safety. Mike has assisted companies in reducing the risk of product recalls, increasing efficiency, and lowering their total cost of ownership.

Ben Pimblett, Head of Market Management, Metal Detection

Ben has extensive knowledge of metal detection systems and over 17 years of experience in the manufacturing sector. He helps customers understand the benefits of metal detection technology and supports them in choosing the right solution. Ben also has significant experience in the Asia Pacific market, having lived and worked in China.

Mike: Risk assessments are vital for identifying where foreign material contamination in food is most likely to occur on the production line, and which contaminants are likely to be the most prevalent.

The type of foreign material is a huge factor to consider when selecting a contamination detection solution.

Metal detection is a tried-and-true method of detecting and removing metal contaminants, including ferrous, non-ferrous and stainless steels.

X-ray inspection detects metal and other foreign substances that can enter food, such as glass, stones, dense rubber or plastic, and bone.

Conducting a detailed Hazard Analysis Critical Control Point (HACCP) risk analysis is an essential first step before manufacturers can establish which contamination detection solution is right for their application.

Ben: We recommend installing product inspection solutions for foreign material screening at key points on the production line to maximize your food safety inspection program.

Front-end inspection detects foreign materials early, before more value is added to your products. It also protects downstream equipment from potential damage caused by foreign objects.

In-process inspection minimizes packaging waste. For example, when product is inspected in-process and prior to the packaging stage instead of being inspected end-of line, it is removed from the process before further value is added. This saves on packaging material and reduces waste.

End-of-line inspection is the last line of defense in contamination detection. After products are sealed in their final packaging, there is minimal risk of foreign materials entering the products. Inspection at this stage further reduces the chance of product recalls due to contamination by foreign materials.

The exact placement and choice of foreign material screening technology will depend on the application and the outcome of the manufacturer’s HACCP assessment. The HACCP assessment is vital for finding and mitigating risk.

Mike: Compliance with food safety requirements is essential for protecting businesses from the threat of product recalls and the resulting brand damage. Contamination detection supports compliance with Global Food Safety Initiative (GFSI) recognized standards by significantly lowering the risk of contaminated products reaching consumers.

Several food safety programs fall under the GFSI remit, including BRCGS, FSSC22000, SQF and IFS. These four programs form 90 percent of all adopted standards globally. Crucially, GFSI-recognized standards help manufacturers comply with food safety laws and regulations.

So, metal detection and x-ray inspection systems support compliance with these programs by quickly and efficiently detecting and removing foreign body contaminants, dramatically minimizing the risk of product contamination.

Ben: Industrial metal detection systems can identify all types of metals, including ferrous (chrome, steel, etc.), non-ferrous (brass, aluminum, etc.), and magnetic and non-magnetic stainless steels. These are available as conveyorized, vertical and gravity, and pipeline systems. Metal detection relies on differences in magnetic permeability and electrical conductivity.

Metals with high conductivity and high permeability produce a strong signal, while those with low values for both, like some stainless steel, can be harder to detect. Optimal performance requires a balance of maximum sensitivity, stability, and reliability. For operator safety, automatic rejection, and due diligence, metal detectors must be integrated into high-performance detection systems.

Metal detectors are typically installed at Critical Control Points (CCPs) to inspect incoming raw materials before processing, at mid-production stages, or at the end of production or packaging lines.

Mike: X-ray inspection systems detect a broad range of foreign objects, such as metal, glass, mineral stone, calcified bone, high-density plastics, and rubber compounds. Additionally, they perform multiple in-line quality checks simultaneously.

X-ray technology works by measuring how products absorb x-rays differently. High-performance systems combine advanced imaging, sensitivity, and reliability to automatically reject defective products and support compliance.

Common inspection methods include bulk flow, pumped products and packaged products.

X-ray inspection goes beyond contamination detection by performing various quality checks, including measuring mass, identifying missing or broken products, and checking for damaged packaging.

Together, metal detection and x-ray inspection systems play vital roles in foreign material control programs by upholding product quality standards and maintaining due diligence throughout the production process.

Ben: This is the big question for many food manufacturers! There are multiple factors to consider. For example, if metal is the only likely foreign material contaminant on your line, metal detection is a great choice. If you are concerned about detecting a broader range of foreign objects such as glass, stone, bone or dense plastic and rubber, x-ray inspection is an invaluable tool.

Food manufacturers also need to consider the properties of their products, as well as how they are packaged. For example, products that need to be inspected vertically prior to bagging, such as potato chips, would require a throat metal detector which can be used in Vertical Form Fill and Seal (VFFS) applications. If additional quality checks are required, such as looking for missing or broken components or checking for any product trapped in the packaging seal, x-ray inspection is an ideal option.

A combination of the two technologies is suitable when both are required by retailer contracts, or when multiple foreign object contamination risks are identified at different Critical Control Points. For example, metal contamination is commonly identified as a risk at in-process steps due to the amount of metal used in production machinery. However, additional packaging and integrity checks may be needed at the end of production.

There is no one correct answer to this question. All factors need careful consideration before coming to a decision, and both technologies have their advantages and limitations. This is why we always recommend working with an experienced provider who can work with manufacturers to select the most appropriate foreign material screening solution across the entire production line.

At METTLER TOLEDO we offer a Test Before You Invest program which includes services such as free product testing and rental options to give manufacturers confidence that they are making the most appropriate choice for their application. It isn’t about simply installing a machine; it’s about understanding the risks and challenges of a production process and providing expert guidance to help manufacturers make an informed decision. It is also important for reliable, long-term operation that staff are trained on how to correctly set up, operate, and test the equipment. A service contract supports optimal performance during the life of the equipment.

Final Thoughts

In conclusion, preventing foreign material contamination in food production is vital for protecting consumer safety, brand reputation, and compliance with food safety standards. While metal detection and x-ray inspection systems are indispensable tools for identifying and removing foreign material contaminants, their effectiveness depends on a comprehensive understanding of contamination risks, strategic system placement, and selecting the appropriate technology for specific products and processes. Combining expert risk assessment with tailored inspection solutions minimizes recalls and enhances product quality and operational efficiency.

Collaborating with an experienced partner such as METTLER TOLEDO can guide manufacturers in making informed decisions, establishing robust foreign material screening, and maintaining an effective foreign material control program throughout the production process.

To read more on this topic, download our guide.

Guide: How to Prevent Physical Contamination in Food

Search suggestions

How to Prevent Foreign Material Contamination in Food

How Screening for Foreign Material Contaminants Supports Compliance in the Food Industry

How Screening for Foreign Material Contaminants Supports Compliance in the Food Industry

Meet Our Experts

Mike Pipe, Head of Product Inspection Division UK and Ireland

Ben Pimblett, Head of Market Management, Metal Detection

How can food manufacturers identify potential contamination risks?

Where can contamination detection systems be installed on the production line?

How does contamination detection support compliance with food safety requirements?

How do metal detection and x-ray inspection systems work to remove foreign objects in food?

Which should I choose for my production line, metal detection, x-ray inspection or a combination of both solutions?

Final Thoughts

Search suggestions

How to Prevent Foreign Material Contamination in Food

How Screening for Foreign Material Contaminants Supports Compliance in the Food Industry

How Screening for Foreign Material Contaminants Supports Compliance in the Food Industry

Meet Our Experts

Mike Pipe, Head of Product Inspection Division UK and Ireland

Ben Pimblett, Head of Market Management, Metal Detection

How can food manufacturers identify potential contamination risks?

Where can contamination detection systems be installed on the production line?

How does contamination detection support compliance with food safety requirements?

How do metal detection and x-ray inspection systems work to remove foreign objects in food?

Which should I choose for my production line, metal detection, x-ray inspection or a combination of both solutions?

Final Thoughts

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