Contaminant Detection

Foreign materials come from different sources and are a serious risk for brands and consumers.
Minimize that risk with the right detection solution.

For Every Foreign Contaminant, The Right Solution

Learn more about the most common contaminants, why foreign material detection must be part of your prevention program, and how to determine the best solution for your production line

Contaminants in Depth

Hazardous vs. Unwanted

Hazardous contaminants pose a serious danger to the consumers’ health. Depending on their size and shape, foreign matter contaminants can be a choke hazard, cause injuries to the digestive tract, or dental injuries.

Unwanted contaminants on the other hand won't necessarily be a hazard, but will cause complaints from consumers and damage brand reputation.

Metal

Metal is the most common foreign material found in food and other consumer products. It's important to detect contamination with metal objects as soon as it happens. Not only are they a hazard for consumers, but they can also damage equipment, causing lengthy unplanned downtime. Examples of contaminants are shards, nuts, screws, beads or bolts from the production equipment, buckshot or needles (especially in meat), hair pins, wires, or fragments of metal blades. Metals can be ferrous (magnetic) or non-ferrous (non-magnetic). These categories require different frequencies to be efficiently detected by metal detectors.

Non-Metal

Examples of common, non-metal materials are: bones in processed meat, rubber from equipment and utensils, glass from product containers, or wood from pallets and utensils. Quite often, non-metal materials are also inadvertently collected from the field when produce is harvested, and while the rinsing and sifting steps will get rid of most of them, they can still contaminate production lines downstream. Contamination with non-metal objects is on the rise. The most effective detection technology is X-ray, which measures the difference in density between inspected product and the foreign material.

What Can and Can’t Be Detected

Commonly Detectable Contaminants

Ferrous and non-ferrous materials, stainless steel, wires, aluminum, bones, glass, and stones.

Difficult to Detect Contaminants

Wood, plastic, human hair, glass fragments in glass containers, and low-density contaminants in general.

Depending on Performance Factors:

Factors include: detection field, aperture size, product orientation, product conductivity, density, packaging, and more.

Our Detection Solutions

X-Ray vs Metal Detector

In an X-ray system, a tube on one side of the tunnel generates a short-wavelength X-ray beam, which is detected by a sensor at the opposing side. As the product passes through the beam, it absorbs part of it. The denser the products and the contaminants, the more energy they absorb. A processor converts data from the detector into grayscale images, isolating density spikes to distinguish foreign objects and creates a density graph of the product. As most contaminants have a higher density than products (for example, metals are eight times as dense as meat) they will absorb more energy and appear as darker spots in X-ray images.

In a Metal Detector, products pass through a magnetic field generated by transmitter coils. When a product is contaminated with a metal object, it disrupts the signal. This disruption is identified by the receiver coils and analyzed. Products above the reject threshold are flagged as positives and rejected. Ferrous metals with lower resistance and higher conductivity (such as copper or carbon steel), generate a greater disruption and are more easily detectable. Non-ferrous metals are also detectable, but will need a higher frequency. As there's no single frequency that can find all metal contaminants in all products, multi-frequency metal detectors ensure a higher performance.

Contaminant Detection Capabilities

With Metal Detectors: alloys of magnetic ferrous metals and aluminum. Dual-frequency Metal Detectors can detect both ferrous and non-ferrous metals simultaneously, minimizing false positives.

With X-ray systems: high-density ferrous, non-ferrous, and stainless-steel metals. Mid-range density materials such as aluminum, glass, stones and calcified bones are also detectable.

Contaminant Detection Challenges

With Metal Detectors: stainless steel has almost no magnetic properties. To be detected, it needs a high frequency, which can affect performance on other metals.

With X-ray systems: contaminants with the same density as the base food product, such as wood, cartilage (as it lacks calcium), bugs, common plastics such as gloves, blue bags, pens, etc.

Why Add Contaminant Detection

To Reduce Recalls and Complaints
Foreign contaminants are one of the main causes of product recalls, which cost food manufacturers millions per recall. Their impact is not limited to the financial cost of recalled products and production loss due to downtime. Crisis management, root cause analysis and corrective measures require a considerable amount of time too. Even when no recall is issued, consumers’ complaints can damage brand reputation and revenue in the long term.
Complying with Government Regulations
There is no ‘safe’ size for foreign contaminants. Even the smallest fragment in a food product might be considered as a potential cause of traumatic injury by the FDA and subject to a product recall.
Managing Risk
Whether you follow the USDA’s or FDA’s regulations, X-ray systems and Metal Detectors are essential for minimizing risk in any HACCP plan. They are a reliable safety net for preventing costly recalls, validating the efficacy of your preventative maintenance program and the other preventive measures.
Maximize Return on Investment
Investing in foreign object detection will not only minimize the risk of recalls, complaints, and lawsuits. Every time a foreign contaminant is detected, it will give you the opportunity to make your preventative measures more effective and advance the level of your quality and safety program. Reducing product giveaway and minimizing downtime will also aid in maximized ROI.

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Determining the Best Detection Solution

One Primary Contaminant Target

The first step is to identify a primary contaminant target (metal, non-metal, glass, bones, etc.) based on the specific risk assessment for your unique production line.

Application Properties

The right detection solution will also depend on the product’s properties: Size, density, shape, line speed, and type of packaging.

Production Line Placement

The third step is to identify the best point in the production line to place the detection equipment. Typical placements would be at the filling step, after primary packaging, or after secondary packaging.

Rejection

A detection solution wouldn't be complete without a rejector that removes faulty products from the production line. The type of mechanism will depend on the product. For example: a flipper rejector for boxes and thick bags or a dropout rejector for thin bags.

The Future of Contaminant Detection

Automation
To improve efficiency and compensate for labor shortages, many processors have increased automation. However, a greater use of technology also creates a higher risk of foreign material contamination: more equipment and a smaller labor force means higher probability of machine components falling into food during processing and fewer visual checks to spot them. Using effective detection systems has become crucial to keeping that risk under control.
Globalization
In a supply chain where food products and ingredients are processed and shipped across the world, international brands are increasingly designing foreign object detection solutions as part of a global strategy, rather than on a facility basis.
Emerging Technologies
- Advanced X-ray – Dual Energy Inspection
- Hyperspectral
- Vision Systems
- Near-Infrared (NIR)
- Ultrasonic
- Thermal imaging

FAQ

What performance factors affect detection capabilities of Metal Detectors?

The performance of metal detectors depends on the level of disturbance to the magnetic field generated by a contaminated product. Metal detectors protect from all metal contaminants except stainless steel. They’re very effective against aluminum too, although they might give false positives with metalized film or foil packaging. Other factors that influence performance are aperture size, product orientation, and product conductivity.

What affects X-Ray detection capabilities?

X-ray systems find foreign matter based on the difference between the density of the contaminant and the density and thickness of the product. They protect from all metal contaminants except aluminum, and won't be affected by metalized film or foil packaging. With low-density materials (e.g., wood, plastic, and glass), their detection performance will depend on the size of the foreign object and the inspected product.

What is detectable by X-ray systems?

Metal, stone, glass, bone, rubber, porcelain, quartz, and aluminum are reliably detectable. Plastic, wood, hair, bugs, latex gloves are generally difficult to detect.

Can X-ray machines detect plastics, band-aids, hairnets, bugs?

No. These types of low density items or contaminants are rarely detectable by an X-ray machine. And even though many plastics are a “hard” material, they do not have any density. Therefore, the X-rays penetrate right through these items/materials and are not seen by the X-ray energy.

Should I remove my metal detection machine when I install an X-ray machine on my production line?

If possible, our recommendation is to maintain both the Metal Detector and X-ray machine on a production line. Processors will benefit from using both, as there might be instances where a metal detector will find matter that an X-ray system cannot. Such detection may include clusters of metal particles that are typically too small for X-ray to locate, and thinner material, including aluminum foil.

Does product temperature affect X-Ray detection capability?

No. Unlike metal detection, product temperature does not impact X-ray performance.

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Contaminant Detection

For Every Foreign Contaminant, The Right Solution

Contaminants in Depth

Hazardous vs. Unwanted

Metal

Non-Metal

What Can and Can’t Be Detected

Commonly Detectable Contaminants

Difficult to Detect Contaminants

Depending on Performance Factors:

Our Detection Solutions

X-Ray Systems

Metal Detectors

Checkweighers

X-Ray vs Metal Detector

Contaminant Detection Capabilities

Contaminant Detection Challenges

Why Add Contaminant Detection

To Reduce Recalls and Complaints

Complying with Government Regulations

Managing Risk

Maximize Return on Investment

Anritsu Academy

Anritsu Product Line

Xray Inspectionand Food Compliance

X-Ray Inspection Systems Table

M6 Metal Detectors