Metal Detection Basics in Food

Learn the Basics of Metal Detection in the Food Industry to Support Food Safety and Product Quality.

Learn all about metal detection basics in food production in this useful know-how page from METTLER TOLEDO. Metal detection is one of the most widely used inspection methods in the food industry. It detects and removes metal fragments that might enter the production line, helping to protect both consumers and brands. From raw ingredients to packaged goods, this vital process plays an essential role in food safety.

Watch our short video and explore our infographic to learn more about the basics of metal detection in the food industry.

Metal detection basics in food | Infographic

Food manufacturing has many moving parts and involves the use of extensive equipment and machinery, from mixing and filling to sealing and packaging. During the entire production process, small pieces of metal can enter the production line, from broken machinery and tools to personal effects such as jewelry. Metal detection systems identify these contaminated products and automatically reject them from the line. This helps to prevent potential damage to processing equipment downstream, reduces costly recalls, protects consumers, and helps manufacturers meet strict food safety standards around the world.

Metal detection basics | How does it work?

How Does a Metal Detector Work?

Industrial metal detectors operate by using three coils wound around a supporting frame to create an electromagnetic field. When a product passes through this field, if it contains any metal contaminants, the electromagnetic field is disturbed. This disturbance triggers the detector to send a signal to a reject mechanism, which then automatically removes the contaminated product from the production line.

Metal detectors can identify ferrous metals such as chrome and steel, non-ferrous metals like brass and aluminum, as well as both magnetic and non-magnetic stainless steels.

For conveyorized applications, the metal detector must be integrated into a high-performance conveyor system designed for operator safety, automatic rejection, and due diligence.

Typical inspection formats include:

On conveyors for both packaged and unpackaged products
Gravity-fed including vertical, form, fill and seal (VFFS)
In pipelines for liquids, pastes and slurries

Inspecting products with metal detectors

Which Types of Products Can Be Inspected?

Metal detection is used in many food applications, whether unpackaged or fully sealed. Unpackaged products such as solids, powders, liquids, slurries, or pastes are often inspected before packaging. This helps make sure the base ingredients are free of metal contaminants, potentially saving costs further downstream. Packaged goods, including trays, pouches, cartons, and boxes, can also be checked once sealed. This adaptability allows manufacturers to integrate metal detection solutions into their existing production lines, helping to keep every product free from metal contamination.

Where on the Line Can a Metal Detector Be Installed?

Metal detection systems are typically installed at identified critical control points across the production line. At the start, metal detectors can check incoming ingredients to catch any metal contaminants before processing begins. Mid-line systems monitor products as they move through filling, mixing, or forming stages, helping to identify problems early. At the end of production, metal detectors can complete a final inspection of packed goods. This step-by-step approach keeps products consistent, compliant, and safer, avoiding costly product recalls in the future.

Metal detector installed in manufacturing

Inspect packaged products for metal contaminants

The Benefits of Metal Detection

Metal detection adds measurable value to food production. It helps maintain food safety, reduces waste, and protects expensive machinery from damage caused by metal fragments. By removing contaminated items early, it keeps production flowing smoothly and avoids the disruption of recalls or product rework. For manufacturers, that means greater efficiency, less downtime, and consistent delivery of products that consumers can trust—all achieved with one reliable technology.

Modern food safety is built around three simple goals: Inspect. Protect. Comply. Proven metal detection solutions from METTLER TOLEDO support manufacturers in multiple ways:

Inspect every product for metal contaminants, automating quality control processes.

Protect brands, profit and productivity by removing any products that don’t meet quality standards.

Comply easily with industry requirements such as standards, regulations and legislation, using proven metal detection solutions from an industry expert.