Product inspection in the food industry

Posted October 13, 2011 in Bulk Inspection, Product Inspection
Product Inspection in the food industry

The necessity for the control of metal contamination in food products has long been practised by conscientious food producers, but never before has the regulation of the safety standards within the food industry been so fiercely regulated. These days the application of quality control and product inspection is monitored at every stage of the manufacturing process, and regulators expect nothing less than the highest standards of safety. To ensure that these standards are maintained the quality control practices are verified and assured by independent inspectors such as the European Food Safety Inspection Service (Efsis) and British Retail Corporation (BRC).

Although food producers have been prime movers in the drive to ensure the highest standards of food safety and have been directly responsible for the implementation of improved quality assurance, it should also be recognised that another major factor has been the demand from the main supermarket companies for the enforcement of such quality controls. Market forces are so exacting, that these major players in the food industry have to take the greatest care to ensure that all of the products produced in their name meet the most rigorous standards. Supermarkets have therefore attempted to enforce these standards through a code of practice for the prevention of metal contamination in food products. Each of the major supermarkets has drawn up such a document and issued it to all of their suppliers of food products.

This implementation of quality assurance practices has driven additional research and development into the manufacture of metal detection equipment, and led to new metal detection machinery that boasts microprocessor-controlled technology with inbuilt software to assist and ensure due diligence.  Today the metal detection system has a minimum requirement to reject a contaminated product from the production line, whilst providing accurate confirmation of the rejection. This is wholly dependent on accurate timing and speed control devices, to ensure that the precise product is rejected, especially on ever increasing high-speed production lines. The introduction of inverter controls, integrated into the main power supply of the metal detector ensures that this is carried out accurately, as it enables the reject timing to be automatically determined by the metal detector, even when the line speed is raised or lowered remotely or manually.

The quality assurance of an accurately calibrated metal detector has to be verified through constant calibrated checks. These checks are carried out by qualified product inspection staff. Part of their job is to conduct regular sensitivity tests, the timing of which is guaranteed by a programmable demand from the metal detector. The test involves sensitivity checks with samples of various magnetic, non-magnetic and inoxydable metals, and this testing programme is itself verified. This verification is controlled by the metal detector recognising and confirming that the metal test samples employed are of the correct metal type, dimension and electromagnetic conductivity, demanded by the actual product being inspected.

The latest editions to the codes of practice issued by the supermarkets now demand even stricter quality control practices. These include the request for the various test samples of ferrous, non-ferrous and stainless steel to be passed through the metal detector in consecutive test products, to ensure that the electromagnetic field is totally stable and capable of full recovery from disturbance by one metal contaminant prior to the immediate introduction of another metal contaminant.
Obviously the most important requirement for any reliable metal detector is the ability to generate a stable and perfectly balanced electromagnetic field. The new mechanised production techniques employed by the food industry have contributed significantly to a major transformation in the design and performance of metal detection equipment to ensure field stability.

In recent years, this has led to major investment by companies like Lock Inspection, one of the world’s leading metal detector and product inspection manufacturers, to move away from the traditional hand built methods to automated production techniques, thus ensuring that the metal detector is accurately assembled with reliable repeatability and perfectly formed coil assemblies which do not require pre-balancing during manufacture or re-balancing when installed in the food processing line. The introduction of programmable laser profiling machines, programmable case bending machines to control internal stresses, automated case alignment and programmable welding machines have all enhanced the performance and reliability of modern metal detectors.