In food safety management, metal detection and X-ray inspection has rapidly evolved from precautionary measures into a pillar of food safety integrity. However, food manufacturers globally are experiencing unprecedented pressure to manage workforce shortages and rising production cost as regulatory standards tighten and production speeds get faster. The result is manual testing of inspection systems has become increasingly inconsistent, labor-intensive, costly and prone to human errors.

The operational risks of relying on manual testing methods can be significant. For example, compliance gaps not only undermine food safety protocols but also increase the likelihood of missed contaminants. Additionally, manual testing introduces greater risks of unexpected machine downtime. This downtime can disrupt production schedules, leading to delays and decreased manufacturing productivity.

All these inefficiencies, production interruptions and potential compliance issues can have a negative impact on operational profits. To address this and to mitigate future contaminant hazards, food processors are switching to automated routine food safety tasks.

On demand documentation

For any inspection system designated as a critical control point, regular performance testing is a non-negotiable requirement of food safety management. In the eyes of auditors and regulatory bodies, the governing philosophy remains absolute — “if it isn't documented, it is like the test never happened.” 

Documentation is the ultimate proof of safety. Failing to maintain rigorous records does not just lead to failed audits, it creates a systemic liability that can result in Class I recalls and the erosion of brand equity and trust.

A comprehensive test log must capture specific, granular data. This helps to ensure compliance with new rules, including the upcoming FDA Food Traceability Rule (FSMA Section 204).

These records should include: 

• Facility information: Location and exact date.
• Metal detector configuration: Specific model, line ID and reject mechanism type.
• Test sample specifications: Verified sphere sizes for ferrous, non-ferrous and stainless steel.
• Precise time of test: Including exact pass/fail status for both detection and rejection.
• Documented corrective actions taken: For each verification failure.

Although these records are vital for demonstrating compliance and ensuring food safety, relying on manual methods to fulfil documentation mandates can lead to inconsistencies and errors introduced by operators. This variability undermines the reliability of the documentation, making it vulnerable to scrutiny and potentially compromising the integrity of a food processor’s entire record-keeping process.

With FSMA Section 204, food manufacturers will be required to deliver electronic records within 24 hours. This strict timescale is accelerating the switch to automated solutions such as Halo Automatic Testing.

Configuration and sector-specific testing challenges

There are several operational and environmental factors that also influence the reliability of test sequences. These vary by application and the physical layout of inspection machines.

Specifically, gravity metal detectors inspecting ingredients and snacks are notoriously difficult to test. As enclosed systems positioned between hoppers and bagging systems, drop points are often inaccessible. Climbing up ladders to access points is time consuming, labor intensive and a health and safety risk. Additionally, test balls are rarely dropped from a sufficient height to fully challenge the reject, and it is impossible to ensure the sample passes through the weakest point of the aperture repeatably.

Proper inline testing of pipeline metal detector systems is equally time consuming and can cause a lot of machine downtime and wasted product as it often involves installation, removal and sanitation of insertion and removal sections to the pipework around the metal detector. As a result, operators often perform tests “alongside the pipe” close to the coils. This completely bypasses the geometric center, rendering the test scientifically invalid for the product that is flowing inside the pipe.

Conveyor system tests are also less reliable as machine operators frequently use preconstructed test packs.  These packages are prone to damage, deformation, additional contamination and the test sample, after some handling, may not be running in the geometric center of the aperture. This means the metal detector’s sensitivity limits is not being fully challenged and even the physical rejection of product may not be simulating real product conditions. 

A global producer of frozen fries installed Halo Automatic Testing on 25 Fortress Technology Stealth Metal Detectors to eliminate human errors and save on operational and labor costs. Testing bags of fries ranging from 0.5 lbs. to 20 lbs., the Halo system automatically adapts to each SKU, adhering to individual customer standards. Production only halts if there’s a detection or rejection failure during the performance verification.

Tests are pre-programed hourly for three metals in three separate positions to counteract masking and verify the reject system is working. Delivering standardized testing, continuous verification and secure digital records that support traceability and future artificial intelligence (AI) initiatives.

Scientific simulation

Automatic testing tools like Halo addresses all these systemic weaknesses. When implemented alongside HACCP plans, they also add a high-frequency verification layer that ensures every metal detector is functioning as expected without human intervention.

Strategic quality assurance, for instance, requires testing the ‘worst-case’ scenario and replicating true production conditions. Halo accomplishes this by replicating electromagnetic field disturbances of specific test spheres in each aperture position. For example, signals increase exponentially as they move closer to the aperture walls. 

Manual tests can inadvertently ‘cheat’ the system by passing samples near the coils or off center in the aperture. Automatic testing instead replicates the performance verifications in the exact geometric center of a metal detectors aperture, providing a true ‘worst case’ challenge.

Lastly, automatic testing should be able to adapt to product effects. Rather than static verification, Halo Automatic Testing introduces its signal directly into the product flow, effectively simulating a contaminant hidden inside a moving package that can be set to cycle leading edge, trailing edge and center of package positions.

Repeatable and robust

Any CCP is only as robust as its reject mechanism. If a system detects metal but fails to remove it, it cannot be considered a functioning system.

To guarantee effective rejection, Halo is developed to operate in conjunction with Fortress Technology’s robust reject monitoring and tracking software that is built into all Fortress digital metal detector models. This integrated approach enables the monitoring of the entire reject cycle, including the precise timing of each reject action, product position and any other sensor monitoring anything related to the reject. 

For optimal reliability, it is essential that any automated testing system utilizes independent hardware for signal generation. This ensures that the process remains autonomous and prevents the system from effectively "grading its own homework."

The move to automatic testing signifies a fundamental change, transforming quality assurance from a perceived burden into a strategic asset. Manual reporting practices divert valuable resources from higher-value tasks related to quality and operational efficiency. By minimizing the need for manual input, resources can be redirected towards more strategic responsibilities.

This shift not only delivers substantial labor savings but also significantly enhances Overall Equipment Effectiveness (OEE). Automatic testing has also been shown to reduce Mean Time to Repair (MTTR) by eliminating downtime associated with manual testing cycles.