Mettler-Toledo Safeline Due Diligence Enhancement for its metal detection systems

Mettler-Toledo Safeline has launched its Due Diligence Enhancement for its metal detection systems to strengthen control and security at critical control points (CCP) on food processing and packing lines. Multiple design features ensure the metal detection enhancement delivers an increased level of failsafe functionality resulting in increased product safety as well as compliance with legislation and retailer guidelines. Food manufacturers also benefit through avoiding the risk of product recalls and potential damage to their brand reputation.

A key focus of the Due Diligence Enhancement is on ensuring that contaminated packs are properly removed from the line. This is achieved through a fully automated rejection system with multiple pack sensing and control devices. The automatic reject mechanism is controlled via input from both the metal detector and the pack sensors enabling the contaminated product to be efficiently removed without stopping the production process. In the event the correct pack has not been removed, a reject confirmation sensor reports this to the system and an alarm is triggered, providing full failsafe functionality.

As an additional guarantee of accurate rejection, a secondary reject check sensor further along the conveyor belt signals a fault should the rejection mechanism fail or the pack in-feed sensor malfunction. If there is any failure, then an alarm is activated, stopping the machine. All activity is monitored and documented within the detector, providing additional confidence that all control measures have been taken to ensure product safety.

It is postulated that a principal cause of metal-contaminated products reaching the consumer is procedural failure, such as the inadvertent replacing of rejected products on the production line after inspection, rather than metal detector failure. Providing a tunnel guard on the out-feed conveyor prevents external interference with inspected packs and ensures that only uncontaminated products are advanced for final packaging and distribution, lowering the risk of expensive and damaging product recalls.

To further safeguard against procedural error, the Due Diligence Enhancement features a lockable reject bin to prevent the placement of rejected packs back onto the conveyor. Access to the reject bin is gained through the touch-screen interface of the metal detector, which includes a high-security password protected operator access and event logging system. This system records all operator access and unauthorised login attempts, ensuring only authorised personnel can access the metal detector controls and the reject bin.

The Due Diligence Enhancement also features condition monitoring technology within the detector that provides advanced warning of adverse trends that could lead to downtime, for instance an increased number of contaminated products. For flexibility, manufacturers can choose between various automatic contaminated pack reject mechanisms depending on the line and pack speed, pack weight and dimensions and the nature of the packaging material.