Food metal detectors are among the oldest inspection systems in the food industry. Although they come in different types, all have the vital capability of detecting metal particles to minimize the risk of contamination.
The chief limitation of these detectors is their incompatibility with foods in metal packaging. Thus, food products that can be inspected by a metal detector include anything not canned or foil-wrapped. However, what other food products can be inspected?
Food Products Commonly Scanned By Metal Detectors
A food metal detector works using the principle of electromagnetic pulse induction (PI). When food products pass through the detector’s magnetic field, any metal contamination will create an electric current. The detector’s receiver coils register the contaminated product, which then passes off the production line.
Food manufacturers use metal detectors for products in non-metallic packaging, like the ones listed below.
Meat and Poultry Products
Meat and poultry are among the most common products subject to food metal detectors. Since these are wet products, they have a comparatively high conductivity, which can create what’s known as the “product effect.”
In other words, the moisture and salt content of meat and poultry might produce a signal similar to detectable metals and throw a detector off. However, this usually isn’t a problem when using an advanced, high-sensitivity metal detector like the ones from TDI Packsys.
Dairy Products
Like meat, fish, and poultry, dairy products such as yogurt and cheese contain a lot of moisture and salt, and may mimic metal signals. In this case, too, it’s important to choose a metal detector suitable for wet products.
Baked Goods and Confectionery Items
Food metal detectors also work great for detecting metals in baked goods and confectionery items. These products may be dry or wet, but a good-quality metal detector should still detect metal contaminants with a high level of accuracy.
Packaged Food Products
Food metal detectors are suitable for packaged food products that aren’t canned, foil-wrapped, or packed with metalized film. Keep in mind that even metal inserts or a small amount of metal in packaging will interfere with a food metal detector.
Frozen Foods
Frozen foods are also on the list of food products that can be inspected by a metal detector. A potential issue with frozen foods is that if the product starts to thaw, its conductivity may rise and interfere with the detector’s signal.
Key Considerations in Metal Detecting Different Food Types
As we’ve already mentioned, a food metal detector “sees” various types of food differently. Keep the following in mind when scanning food products for stray metal particles.
Variations in Product Density and Composition
The chief factor influencing a food metal detector’s work is conductivity. Moist products with a high salt or mineral content will be more conductive, making it harder for the detector to spot small metal particles. A metal detector that uses a wide frequency spectrum can help overcome this issue.
Impact of Packaging Materials on Metal Detection Efficacy
Any packaging with metallic elements, including a thin metalized film, will throw off a food metal detector. Foods in metal-containing packaging must undergo scanning before packaging. After packaging, you must rely on other inspection systems, like food X-ray machines, to detect contaminants.
Adjusting Metal Detector Settings for Different Food Products
A food metal detector should locate unwanted metal particles accurately and consistently. At the same time, you don’t want the detector to raise false alarms. An oversensitive detector could lead to unnecessary rejections and a lot of waste.
You must adjust the metal detector’s frequency for different food products. High frequencies work best for dry products, while a combination of low and high frequencies produces better results with wet products.
Common Contaminants Detected by Metal Detectors in Food Products
Metal particles can infiltrate food products at various stages of production, from the raw materials to the packaging process itself. A quality inspection system will be able to detect any type of metal, whether ferrous, non-ferrous, or stainless steel.
Ferrous Metals
Ferrous metals (i.e., iron or iron-containing alloys) are magnetic and have good electrical conductivity. These are usually the easiest metals for food metal detectors to recognize.
Non-Ferrous Metals
Non-ferrous metals, like copper, lead, and aluminum, are non-magnetic and have good to excellent conductivity. Like iron, these metals usually pose no challenge to a food metal detector.
Stainless Steel Contaminants
Stainless steel is usually non-magnetic and typically has poor electrical conductivity. This is the hardest type of metal to detect in food products. The detection accuracy may depend on the composition of the stainless steel particle and the detector’s sensitivity.
Best Practices for Implementing Metal Detection Systems in Food Production
As a food manufacturer, you know it’s critical to identify contaminants in food products that can be inspected by a metal detector. One hidden metal particle could damage your reputation and trigger expensive recalls and lawsuits.
Metal detectors may be ubiquitous in the food industry, but that doesn’t mean all detectors work equally well for all products. Moreover, you must use your detection equipment correctly for the best results.
Equipment Selection and Calibration
Choosing the right food metal detector is a critical step in your quality assessment process. You must consider what type of screening your metal detector will tackle.
For example, a metal detector that works well for dry products may not fit a meat or dairy production line since detecting metal contaminants in dry foods is much easier. Consider detector sensitivity, as you need a detector that can help you weed out contaminated products without the waste of too many false rejects.
Once you select your metal detector, you must also calibrate it properly. Choose a reference standard matching the type of metal contaminants in your application. This will ensure your metal detector complies with industry regulations and delivers accurate results.
Operator Training and Maintenance Procedures
Production line workers will also need training to use the metal detection system correctly. All food metal detectors need regular maintenance to keep working accurately and safely. Proper maintenance will also help extend the life of your metal detector.
Operators responsible for maintenance must inspect the system for any damage and wear, periodically recalibrate the detector, perform signal tests, and examine the conveyor belt for misalignment. Also, any production line machinery should undergo rigorous cleaning and sanitization.
Integration With Overall Food Safety Management Systems
Metal detectors play a key role in ensuring the safety of food products. However, if there’s a risk that non-metals like glass, plastic, or rubber could contaminate your food products, consider investing in an x-ray inspection system.
You’ll need an all-encompassing food safety management system (FSMS) that covers everything from receiving raw materials to distributing packaged products. This includes an efficient hazard control plan, intensive food safety training for your team, and a recall and traceability system.
Find Quality Food Metal Detectors With TDI Packsys
Top-tier metal detectors by TDI Packsys protect your consumers and your company’s reputation. Our metal detection systems are suitable for all food products that can be inspected by a metal detector, including meat and poultry, baked goods, and any foods in non-metallic packaging.
Contact us today to learn more about our products and choose the ideal metal detector for your application.
