The Most Important Qualities of Any Food Metal Detector Program

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meat in vacuum packings with vegetables on wooden table

If you run a food production or packaging line, the last thing you want is to end up on the evening news because a customer found metal shavings in your products. Food metal detectors can help you avoid such a disaster, but you might wonder where to begin if you’ve never purchased one.

What are the most important qualities to look for in a food metal detector? The answer to that question depends on your business’s needs. If you need a metal detector capable of finding stainless steel, for instance, it’s unhelpful to buy one that can only pick up ferrous metals.

Below, learn about some must-have qualities for food detectors to help you pick the best one for your business.


Did you know the Food and Drug Administration (FDA) prohibits metal fragments between 0.3 and one inch in food products? It’s virtually impossible to find metal pieces that small with the naked eye, which is where food metal detector sensitivity comes in.

Metal detector sensitivity refers to a machine’s ability to pick up on true contaminants while minimizing false rejections (items flagged as metal that aren’t). Many companies assume they need a detector capable of maximum sensitivity, but that’s not necessarily true. To pick the right sensitivity, you must consider:

  • The type of metal you need to detect. Ferrous metals are easier to detect than non-ferrous metals.
  • The type of products you want to scan. It’s easier to detect metal in solid food than in liquids. Products with a high salt content, such as cheese and processed meat, may trigger false rejects.
  • Available aperture size. The smaller you set the machine’s aperture, the more sensitive it will be.
  • Your building’s environmental conditions. Airborne electrical interference or temperature fluctuations can affect scan results. If your building regularly experiences either, choose a machine capable of taking such interference into account.


As mentioned above, you don’t want your food metal detector to flag something as metal when it’s not. That slows down your production line and costs you money if you discard perfectly good products for no reason.

On the other hand, if your metal detector misses contaminants, you could end up with a product recall or lawsuit. You care about your reputation and bottom line, so this is just as unacceptable as false rejects should be.

Food metal detector accuracy ties directly into sensitivity. If yours is too sensitive, you’ll have false rejects. If the sensitivity isn’t high enough, the machine will miss contaminants.

Accuracy is especially important if you produce foods high in moisture or salt. These foods commonly trigger false rejects in a phenomenon known as the product effect.

To avoid this, you’ll need to buy a metal detector that combines product signal suppression and multi-simultaneous frequency technology. These machines work by minimizing the active product signal.


engineer thinking where to put the food metal detector

Where do you plan to install your food metal detector? At the beginning of the line, at the end of the line, or somewhere in the middle? Maybe you’d like to put a metal detector in all three places. This could be a good idea because metal pieces can contaminate your products at any stage of their trip down the production line.

The type of metal detector you need depends on where you plan to use it. At the beginning of the line, you might choose a less sensitive detector that can find large metal shavings that fall off other machinery. Near the end of the line, you may prefer a highly sensitive metal detector that can pick up on metal debris through product packaging.

You should also consider whether you need a metal detector in a demanding environment. If you operate in a building with high humidity or corrosive materials, you’ll require a metal detector capable of withstanding those conditions.

Lastly, consider the utilities available at your building. Some metal detectors run on electricity, while others rely on compressed air.


Durability is one of the most important qualities of a food metal detector. If your metal detector breaks down in the middle of the workday, you stand to lose quite a bit of profit.

To avoid such an unfortunate incident, pick a metal detector made from high-quality stainless steel. Avoid detectors containing too many plastic parts, which are prone to breaking under heavy loads and high temperatures.

Also, consider the washdown procedures your environment requires. The toughest food metal detectors are capable of withstanding very hot water, intense pressure, and chemical cleaning solutions.

If you clean your food metal detector with low-pressure and room-temperature water, you can purchase a unit with an IP65 washdown rating. If your environment requires sustained high pressure and hot water temperatures, you must buy a metal detector with an IP69K rating. Purchasing a machine with the wrong rating could lead to malfunctions when cleaning your metal detector.


ferrous and non ferrous metals shard in a factory

If you need to detect ferrous metals, you can get by with a fairly simple metal detector, as these metals are the easiest to detect. But if you’d like to detect stainless steel and non-ferrous metals, you’ll need a more versatile detector.

Not every metal detector can find all three types of metal. Some struggle to find non-ferrous metals such as lead, aluminum, and copper because they’re non-magnetic. Stainless steel is notoriously hard to detect because of its poor electrical conductivity.

You can find food metal detectors capable of locating all three kinds of metal, but naturally, they’ll cost more than a detector that can only find one type of metal.

You’ll also need a versatile metal detector if your business produces several food products. For instance, if you manufacture orange juice and breakfast cereal, buy a metal detector that can switch from one to the other on the fly.

Additionally, consider whether you prefer manual, semi-automatic, or fully automatic controls. Manual metal detectors require a human operator, while fully automatic machines do not. Semi-automatic detectors are somewhere between the two.

User-Friendly Interface

A food metal detector’s user interface allows employees to communicate with the machine. The user interface works by electronically communicating with the detector’s receiving coils and translating their signals into data that workers can use.

The user interface records metal sample tests, quality control tests, and the time/date of detection. If the detector falsely flags something as a reject, operators can check the interface to learn more about what went wrong.

The user interface also allows operators to calibrate the metal detector. During this process, the operator trains the detector on what is metal and what isn’t to reduce the chance of false rejects.

The food metal detector you choose should have an intuitive and easy-to-use interface. If the user interface is confusing, operators will be unable to adjust settings and calibrate the machine properly.

Easy Maintenance

Even fully autonomous food metal detectors need human intervention once in a while. Many business owners consider maintenance time-consuming and frustrating, but keeping up with a regular preventative maintenance schedule comes with plenty of perks. These include:

  • It is far easier to maintain your metal detector in advance than it is to fix major problems later on.
  • Maintenance allows you to monitor overall equipment effectiveness before small issues become costly breakdowns.
  • Maintenance reduces the risk of contaminated products reaching customers.
  • Maintenance enables your business to comply with industry regulations and ensures your food metal detector passes inspections and audits.
  • Maintenance ensures future compatibility with other equipment.

Your food metal detector should be easy to maintain, and training staff on how to do so should be straightforward. Once you’ve purchased and set up your detector, you must establish a regular maintenance schedule. This could include:

  • Checking the machine externally for signs of wear, loose connections, and physical damage
  • Checking the power supply and cables for issues
  • Signal testing to verify the detector’s response to different sizes and types of metal
  • Checking the conveyor belt for misalignment
  • Regularly testing and recalibrating the machine as needed

Cost Effectiveness

hands of businessman holding light bulb with coins inside

While you can buy a fancy and expensive food metal detector, it’s important to ask whether your business needs those bells and whistles. Buying such a machine may not be cost-effective if you could get by with a less advanced metal detector. Additionally, the larger and more advanced a detector is, the more frequently you must maintain and repair it.

Factors that affect the price of food metal detectors include:

  • Type and model
  • Sensitivity level
  • Detecting dimensions
  • Customization support
  • User interface
  • Industry grade
  • Warranty, which some manufacturers factor into the price of the machine


The metal detector you buy should come with thorough documentation that teaches you how to install, calibrate, test, and maintain the machine. If the documentation is inadequate, you may find yourself repeatedly calling the manufacturer for help. Not only can this slow down your production line, but many manufacturers charge extra for service calls.

Your machine’s documentation should provide guidance on training employees on how to operate the detector as well. If yours doesn’t, you may have to call the manufacturer for training, although some will provide this service for free.

Learn More About Our Food Inspection Systems

Now that you’ve learned about the most important qualities of a food metal detector, we welcome you to contact TDI Packsys to learn more about our food metal detectors and inspection systems. We also offer calibration, inspection consultations, training, and after-sales support.

To speak with our team at TDI Packsys, call (877) 834-6750.

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