Food manufacturing and processing facilities rely on many different tools to maintain strict quality control and safety standards, and one of the most important is food metal detectors. This technology benefits consumers and manufacturers by preventing contaminated food from reaching store shelves.
Below, we explain the basics of food metal detectors, including the different types, how they work, common applications, and their importance to the food industry. At TDI Packsys, we’re a trusted supplier to the food industry, offering a versatile range of state-of-the-art food metal detectors and inspection solutions.
What Are Food Metal Detectors?
In the food industry, facilities that produce, process, and package food must follow federal food safety regulations and quality standards. To comply with these regulations, manufacturers use a wide range of tools and technology, including inspection systems like food metal detectors.
As the name implies, food metal detectors can identify the presence of metal particles and objects in packaged, unpackaged, or bulk food items. Over the years, this technology has advanced, improving the level of precision and accuracy during food inspections. Companies within the food processing industry can choose from different types of food metal detectors based on their specific needs, which we’ll discuss further below.
How Do Food Metal Detectors Work?
Food metal detectors use a process known as electromagnetic pulse induction (PI) to identify metal particles or objects within a magnetic field. The metal detector applies a pulsing current to a transmitter coil, which generates a high-frequency electromagnetic alternating field.
As food items travel through the magnetic field, the presence of metal will induce electric currents that trigger a change that varies based on the type of metal and its specific properties. A pair of receiver coils registers the change, then digitally processes and evaluates it.
Types of Food Metal Detectors
When learning about the basics of food metal detectors, it’s essential to explore the different types.
Food metal detector types vary by many different factors, including their suitable applications, the kind of analysis and technology they use, what food products they can scan, and more. The most common types of food metal detectors include:
Flow-Through Metal Detectors
A flow-through metal detector (also known as a pipeline metal detector) analyzes liquid food products, like beverages and sauces. As the liquid flows through the pipe, the detector continually scans for metal contaminants. Upon positive identification, the machine automatically stops the flow of liquid.
Conveyorized Metal Detectors
Facilities that use conveyor belts to move food from station to station often use conveyorized metal detectors. The detector sits above the conveyor belt and points downward, scanning each food product as it travels through its electromagnetic field.
Gravity-Fed Metal Detectors
This type of metal detector uses gravity to pull food products through its magnetic field and scan for metal contamination. Gravity-fed metal detectors are best suited for free-flowing, non-liquid food products in bulk, such as powders, cereals, beans, seeds, etc.
Which Metals Can be Detected?
In the past, it was difficult to detect metals in food, and processing facilities faced many challenges regarding precision and accuracy. However, technology has advanced so far that these devices can now detect minute traces of metal particles. Generally, metal types fall into four categories: ferrous, non-ferrous, stainless steel, and alloys.
Ferrous Metals – Magnetic
Ferrous metals are magnetic, conductive, and high in iron. Since they’re highly magnetic, ferrous metals are among the easiest to detect in food items. Examples include:
- Cast iron
- Carbon steel
- Nickel
- Chromium
Non-Ferrous Metals – Non-Magnetic
Non-ferrous metals are conductive but do not have magnetic properties, as they don’t contain iron. Examples include:
- Aluminum
- Lead
- Nickel
- Zinc
- Brass
- Silver
- Lead
- Copper
Even though they’re not magnetic, non-ferrous metals are still relatively easy to detect because they have electromagnetic resonances.
Alloys – Stainless Steel
Metal alloys contain more than one type of metal. The specific properties of the metal in the alloy impact the ease or difficulty of detection. The most difficult alloy to detect is stainless steel, which contains iron and chromium and is neither magnetic nor conducive.
Foods with salt or water make stainless steel even more challenging to detect. Titanium is another alloy that’s difficult for metal detectors to identify, as it has low conductivity.
Applications of Food Metal Detectors
Food manufacturing, processing, and packaging companies can benefit from the wide range of metal detectors suitable for many different applications.
Dairy Products
Dairy products like yogurt, cheese, and ice cream often have a high salt content. Since salt is highly conductive and can mimic genuine metal signals, this poses a unique challenge for metal detection systems. As such, metal detectors with a high-frequency field are the best choice for detecting products with high levels of water or salt.
Baked Goods and Confectionery
For baked goods and confectionery, “wet” goods and products in metalized film or foil packaging are just as challenging for metal detectors to identify metal contamination and distinguish between product effects (goods with no metal bodies that trigger a positive identification due to their natural conductivity) and other anomalies. However, advances in software algorithms have made it easier, faster, and more reliable for processing plants.
Meat and Poultry Processing
Meat and poultry processing facilities also face the same “product effect” challenges due to the presence of moisture and salt in these products, which make it more difficult for metal detectors to operate accurately. To combat these challenges, metal detection technology that includes variable frequencies, high sensitivity, and advanced software is necessary for products like beef, pork, poultry, slurries, and more.
Pharmaceuticals and Medical Devices
In the pharmaceutical and medical device processing industries, metal contamination from fasteners, buds, pins, equipment pieces, etc., is common. The best types of metal detectors for this industry are those with electromagnetic induction measurement, radio frequency signals, multi-frequency transmission and receiving, and very low-frequency measurement.
How to Choose the Right Food Metal Detector for Your Business
Choosing a food metal detector for your business is an important decision. Ideally, you want to pick a model that suits your specific application and will provide the highest return on your investment. Here are some essential factors to consider:
- Application: What type of food products does your business process?
- Metal Types: What metals are most likely to contaminate your goods?
- Maintenance: How much maintenance will your chosen model require?
- Location: Where is the highest risk point in your production line?
- Size: Can your facility accommodate a large-sized model?
- Cleaning: Do you need a model that can withstand high-temperature or high-pressure cleaning?
- Cost: What is the size of your budget?
- Unique Needs: Does your food product have extra obstacles, like metalized packaging or high-salt content?
- Quality: Will you need a high-tech model with advanced features?
- Reputation: Does the company that manufactures the metal detector have a stellar reputation for quality, service, and reliability?
Why Are Food Metal Detectors Important?
Food metal detectors are essential to ensure the safety of consumers and companies alike. In processing facilities, metal contamination due to wear and tear of the machine, human error, or other mistakes can enter the food. Unfortunately, this is all too common, often resulting in costly and potentially hazardous recalls.
Thankfully, food metal detectors can identify potential contaminants before they reach stores or consumers, making the food supply safer. At TDI Packsys, we proudly help ensure the safety and quality of food products everywhere with our advanced metal detectors. From conveyorized and flow-through models, to gravity-fed and drop-through models, we have a wide selection of metal detectors to meet all your needs.
Want to know more about the basics of food metal detectors? Call the TDI Packsys team at 877-834-6750 to explore our various food metal detectors, and learn how they can benefit your food processing business.
