Foreign Object Detection Challenges in Meat Processing

Food safety is key to food processors to protect product quality and safety. Preventing biological contaminants is a primary concern to meat processors and requires harsh and frequent cleaning procedures. Another key aspect of food safety is ensuring that foreign materials such as metal shavings from machinery and other foreign objects do not enter the process at any stage from raw materials entering the facility, to when supplier ingredients are added to contamination resulting from worn metal equipment components.

Therefore, in the food industry, ‘foreign body’ refers to extraneous physical objects that render the food unfit for human consumption. Detecting foreign material is especially important in meat processing to control product quality and safety.

Product effect: a major challenge in detecting metal contamination

Sentinel contaminants

Detection of metal contaminants using food grade metal detectors can be difficult because meat products have high product effect that can mimic a foreign object. ‘Product effect’ refers to instances where certain food characteristics like high salt or high moisture content trigger magnetic or electrical signals similar to that of foreign material, which then interfere with foreign material detection.

Factors that create product effect:

  • High salt or moisture content.
  • Temperature variations.
  • Wet product (e.g fish, poultry, fresh meat).
  • Packaging material.
  • Product consistency and density.
  • Product size and shape.
  • Product orientation and position on the line.

Some examples of challenging meat applications are:

  • Spiced and salted processed products
  • Deli-style layered slices
  • Sausages
  • Moist or bloody whole muscle cuts
  • Ready to eat meals containing meat

Previously, food manufacturers often have to compromise metal detector sensitivity to avoid false rejections. Fortunately, new metal detection technology can help overcome the aforementioned meat inspection challenges.

Features to look for in food grade metal detector

1. Equipped with user-adjustable frequency to improve sensitivity when faced with high product effect.
Sentinel Multiscan Metal Detector

A common approach to reducing product effect and thereby improving detection performance is to utilize low-frequency, low-energy excitation.

Food grade metal detection technology like Thermo Scientific Sentinel 5000 Multiscan Metal Detector can scan food products using five user-adjustable frequencies at a time, increasing the probability of detection and improving overall sensitivity.

Using Sentinel Multiscan Metal Detector, enables the trained operator to select detection frequencies from 50 to 900 kHz at the push of a button. When a difficult product is encountered, a technician can set up a low frequency schedule better suited to a highly conductive product and optimize performance. Since this technique is not always required, the flexibility to be able to run any frequency on any product is a plus with multiscan. The Sentinel Metal Detector typically exceeds the performance of single frequency metal detectors by 10-30%. Because the frequencies are completely adjustable, the Sentinel Metal Detector is more flexible and can cover a wider range of applications.

When the Sentinel with Multiscan is coupled with a design to survive thermal shock, harsh chemicals, and software to adapt to constant product changes, food processors can achieve a new level of food safety previously unattainable in meat applications.

2. Complemented with software that learns variability and adapts to changes
Autolearn Software for the Sentinel Multiscan Metal Detector

Detecting foreign object contamination can be made more efficient with smart software that can automatically set and adjust operating parameter.

The auto learn routine in the Sentinel 5000 Metal Detector’s software adjusts to the change in product signal. It accepts multiple products at various temperatures, both clean and with the target contaminants. To optimize set up, the data from this product then automatically sets all the operating parameters. By teaching the metal detector in this way it is possible to quickly arrive at a set up that could otherwise take a skilled technician many hours or even days to complete. 

Once in production, it is a fast process to review recent reject data to see if it is necessary to adjust a parameter to eliminate false rejects. To handle phase changes over time, the Sentinel 5000Metal Detector includes a phase tracking capability. Tracking works by automatically adjusting the product phase in real-time as the meat is inspected. Information from uncontaminated meat is fed back using a proprietary algorithm, maintaining performance as the ratio of conductive and magnetic product signals change. The result of this smart, adaptive software is that user intervention is eliminated and throughput is maximized. This is true even in difficult variable product effect meat applications.

3. Designed to meet USDA’s IP69K industrial standard to survive thermal shock and harsh chemicals
Sentinel Multiscan Metal Detector offers a unique HD (Heavy Duty) option

Washdown requirements in the meat industry can be very demanding. The USDA calls for sanitation standards that can include high-temperature and pressure spray-down and use of caustic cleaners. Many metal detectors today are built to the IP69K rating (80˚C water at up to 1450 PSI), but this alone does not provide long-term defense from water intrusion into the metal detector case. The Sentinel 5000 Metal Detector offers a unique HD (Heavy Duty) option for the meat industry to maximize uptime in harsh environments. It was tested and survived up to 10,000 thermal shocks with no degradation in performance.

The HD design enhancements are:

  • Soft epoxy fill and liner resistant to separation from the metal case
  • Complete fill with epoxy eliminating space where water could be trapped
  • Welded aperture flanges to reinforce the liner seams

Comparison table to select food grade metal detectors

Use this comparison table to decide which food grade metal detector is the most suitable for your application. The products are compared based on:

  • Typical install application: either on a conveyor, combo with checkweigher, drop through / gravity, or pipeline.
  • Product type and packaging: cartons/ boxes, pouches / bags, bulk flow products, plastic bottles & jars, tablets and capsules.
  • Design.
  • Frequency range.
  • Typical sensitivity.
  • Temperature: operating temperature, maximum limit.
  • Belt speed range.
  • Aperture.
  • Specific aperture size.
  • Industrial rating standard.