Your food production process likely involves metal in some shape or form. Whether you package your products in cans or use metal equipment during production, you must take every measure to ensure that no metal particles make it into your food products.
Implementing the right technology and protocols to detect metal contaminants is critical to consumer safety and supports your compliance with FDA regulations. Most food industry manufacturers use metal detectors during their quality assurance processes. But what types of metal can metal detectors find, and how do you ensure the most reliable detection for your products?
Understanding Food Metal Detectors
Food metal detectors are devices that scan food as it passes through your production line, looking for metal contaminants within the product. While different metal detectors operate differently, most devices within the food industry work like this:
- The device contains a transmitter coil and two receiver coils that are parallel to each other.
- The transmitter coil creates an electromagnetic field.
- When a food product passes through the electromagnetic field, any metal particle would interfere with it, causing the receiver coils to detect a signal.
- The device transfers that signal to an electronic unit, which evaluates the signal and alerts an employee about possible contaminant detection.
Typically, metal detectors in the food industry include automatic features to reject products that flag the system for metal contaminants. The contaminated product would enter a separate line from the production line, where a worker could review it.
Metal detectors play a pivotal role in ensuring food product safety and preventing harmful contamination. Even if a manufacturer uses the most foolproof production process, they still need checks in place to guarantee that no contaminated food products make it out of the facility.
The FDA has strict standards to prevent the inclusion of metals in food products. The administration recommends using electronic metal detectors to identify metal fragments in finished food products.
Metal detectors offer a reliable method of detecting metal contaminants in products, giving manufacturing businesses a safety net to protect against compliance issues and liability.
Types of Metals Detected by Food Metal Detectors
What types of metal can metal detectors find? Metal detectors cannot detect all types of metal equally. These are the different types of metals and how reliably metal detectors can identify them:
- Ferrous metals: Ferrous metals include any metals that contain iron, such as steel and cast iron. Most metal detectors can easily detect ferrous metals because of their magnetic properties and electrical conductivity. Both of these qualities allow ferrous metals to reliably interfere with the electromagnetic field within the metal detector system, triggering a signal.
- Non-ferrous metals: Non-ferrous metals are those that do not contain iron and are not magnetic. Copper, aluminum, brass, and lead are common examples of non-ferrous metals. Even though these metals are not magnetic, they have excellent electrical conductivity. Metal detectors that use electric fields can usually detect them. However, these systems cannot rely on the metals’ magnetism for detection, meaning detection is not quite as reliable as it is for ferrous metals.
- Stainless steel: Stainless steel is an alloy of iron and chromium. The two main types are austenitic, which is durable and weldable, and ferritic, which contains a higher concentration of chromium. Stainless steel is not magnetic and usually has poor electrical conductivity, making it challenging to detect with traditional metal detectors. A metal detector needs to run a high frequency to induce a current in the stainless steel as it passes through the field, and many modern devices include this feature.
How Various Factors Affect Detection Capabilities
While metal detectors can find some types of metals better than others, that doesn’t mean they detect any metals with 100% accuracy. Many factors can impact the ability of these systems to identify metal contaminants in food items.
Detector Sensitivity Impacts Ability To Identify Small Metal Fragments
Metal detectors can have varying sensitivity levels. A system’s sensitivity depends on its aperture size, which impacts the strength of the electromagnetic field. If the aperture is too large, the sensing field will be less sensitive.
This means food manufacturers should select metal detectors with the smallest aperture for their applications. This allows them to pinpoint the minuscule fragments of metals within small food products.
Certain Product Characteristics Interfere With Metal Detection
The food product’s composition and packaging can also impact the detector’s processes. Certain foods, such as warm bread, cheese, fresh meat, pickles, and jam, have slight electrical conductivity. These foods can trigger the metal detector, producing a false positive reading and slowing production.
Foods with high salt content may trigger the detector because salt is a mineral, mimicking the presence of metal. If a food product uses metal packaging, such as aluminum cans, manufacturers must scan it before the packaging stage to look for traces of metals.
Environmental Factors Can Disrupt the Electromagnetic Field
The manufacturing facility itself can impact the efficacy of metal detectors. If any nearby machines generate electromagnetic fields, these can interfere with the detectors. The facility’s temperature and humidity can also affect electromagnetic readings. Facilities located near the ocean can even have salinity in the air that triggers metal detectors.
Because so many environmental factors can affect metal detection, food manufacturers should work closely with metal detection companies to determine the right system and settings for their facilities.
Benefits of Metal Detection in Food Processing
When executed correctly, metal detection in food processing poses numerous benefits.
Promotes Quality Assurance To Ensure Product Safety
Metal detectors help maintain a food product’s quality and safety. Even one small metal fragment within a food product can cause serious health concerns if ingested, such as lacerations, perforations of the intestine, and the introduction of harmful bacteria into the body.
Passing food products through metal detection systems is a fast way to mitigate this risk and ensure the quality of the items.
Ensures Compliance and Protects Against Liability
The FDA can take regulatory action against companies that distribute food products with metal contaminants. A company may face penalties and potential shutdowns after the FDA finds metal contaminants left behind in even one food product.
A consumer who purchases a contaminated product can also sue for damages, leading to a costly legal process that can make headlines and impact a company’s reputation.
Instills Consumer Confidence To Aid Buying Decisions
When companies advertise that they use strict quality control procedures, including metal detectors, consumers gain confidence in the safety and reliability of their products. A consumer may be more likely to choose these brands over ones that don’t publicize their quality control measures.
Challenges in Detecting Different Types of Metals
While the answer to “What types of metal can metal detectors find?” is fairly straightforward, many factors can disrupt the detection process or limit the efficacy of these machines.
For example, even high-performance metal detectors cannot always identify metal particles embedded in dense or liquid food products. Dense foods may disrupt the signal between the transmitter and receiver coils.
The temperature and moisture content of foods can also disrupt metal detection. Further, different applications require different frequency settings; if a metal detector is not calibrated correctly, it will not accurately pinpoint contaminants.
Best Practices for Implementing Metal Detection
Food manufacturers can improve the efficacy of metal detection systems with these best practices:
- Regular calibration and maintenance: Like any equipment in food manufacturing, metal detectors need regular maintenance to continue performing at their peak. They may also need to be recalibrated to adjust their sensitivity.
- Employee training: Employees should understand the correct way to load products onto the machine so that the metal detector can properly assess them. They should also know how to operate the metal detectors and identify false positives.
- Integration with quality control systems: Metal detectors should fit into a broader food safety and quality assurance framework that includes other types of food detection devices, strict protocols, and precise manufacturing procedures to prevent contaminants.
Is Metal Detection Enough for Food Safety?
After answering the question, “What types of metal can metal detectors find?” it is clear that these devices should not be the only systems within a company’s quality assurance process. They cannot always reliably detect non-ferrous metals or stainless steel, and they cannot identify non-metal contaminants.
Combining metal detectors with other inspection methods, like x-ray systems, provides a more comprehensive assessment of a product’s safety and quality. Manufacturers should have written quality assurance plans that cover all possible sources of contamination and include several different checks, not just metal detection.
TDI Packsys: Your Source for High-Performance Metal Detector Systems
So, what types of metal can metal detectors find? While they can reliably find ferrous metals and many non-ferrous metals, they cannot detect stainless steel or non-metal contaminants. Still, these systems play an invaluable role in food production quality assurance.
At TDI Packsys, we produce industry-leading metal detection systems for food manufacturers. Learn more about our products and consider integrating our advanced metal detection technology into your food safety strategy.
