In the food production industry, metal is the leading contaminant of food products. Consumer protection is the primary reason why metal detectors are used in the food industry. A metal detector can ensure the integrity of goods at the production/packaging stage and prevent any threat to consumer consumption. It is a feasible and intelligent option for production companies as any reported contamination could lead to damaging consequences ranging from product recalls, expensive law suits to a tarnished brand image.
Metal Detectors for the Food Industry
Metal detectors ensure protection against ferrous and non ferrous metal particles such as aluminium, iron, stainless steel, etc. Stainless steel contaminants are more difficult to detect than ferrous and non ferrous contaminants as they are poor conductors of electricity and are non-magnetic in nature.
Food grade metal detectors can be used for milk and dairy products, snacks and biscuits, ready meals, bakery products, meat, poultry, etc. They can be used at every stage of the production process from raw materials where detectors can identify metal contaminants before they could get broken up into smaller pieces; to critical checkpoints during production to identify machinery failure or damaged utensils and lastly at the packaging stage for a final inspection.
Types of Metal Detectors
1 – Balanced Coil Metal Detectors
There are several types of metal detectors which employ different inspection methods. One of the most popular ones used in the food industry is the General Purpose Metal Detector or Balanced Coil Metal Detector. These detectors are equipped with two receiver coils and a single transmitter coil placed around the aperture from which the product goes through. The transmitter coil produces a consistent stream of electromagnetic field which blocks the metal particle when it passes through the field and signals the receiver coils. The electronic unit in the detector then analyzes and evaluates the particles and excludes them from moving to the next stage of production.
2 – Ferrous-in-Foil Metal Detectors
These detectors have a small passage with a series of coils and a strong magnetic field. When any metal particle with a ferrous element passes through it, it is magnetized and generates a current which then signals the electronic unit of the detector and sets off the alarm. This type of detector can detect aluminium, iron, stainless steel, etc. It is mostly used for products packed in foil such as pies in aluminium foil trays.
Detector sensitivity refers to the aperture size of the metal detector. Simply put, the smaller the aperture of the detector, the better the efficacy to detect tiny pieces of metal. The length and dimension of the aperture determine its sensitivity. The position in the aperture also impacts sensitivity. For example, the centre is the least sensitive area whereas the sides and coils have higher sensitivity. It is imperative to set the sensitivity level for each product under scrutiny depending on its size, packaging, type, shape, etc.
Modern metal detectors have fully integrated user interfaces which communicate with the electronic unit of the detector and also convert signals into functional data. An ideal user interface records test results, provides analytical information, statistics, and maintains historical information. A user interface plays an important role in streamlining and managing metal detectors and also help to track errors in case of a recall.
Food Industry / Retailer’s Guidelines
Some important retailer’s guidelines to bear in mind when using metal detectors in the food industry include:
- Suitability and location – The selection, positioning and design of the metal detector is best determined by a risk assessment and suitability analysis. This analysis is done by reviewing steps involved in the process of production and the likelihood of contamination at each stage.
- Configuration – An automated Reject system will remove any contaminated item directly from production flow. A manual Reject system will trigger an alarm or signal to alert an operator about any deviancy.
- Sensitivity Performance – Sensitivity Performance, as elaborated above, is the aperture size of the metal detector. Sensitivity can be impacted by product, environment, packaging and overall presentation of the product. The metal detector manufacturer or supplier can help to set or test the sensitivity level from time to time.
- Testing – Specific metal detector test samples must be used to test the efficacy and efficiency of the unit. These include spheres in a suitable carrier to be inserted into the product or packaging.
Today, the food industry produces products at a faster rate than ever before. Therefore, it has become more crucial than ever to maintain quality and efficiency standards. Incorporating a modern tech-based metal detection system is the most coherent option compared to the drastic consequences of producing unsafe products.
Photo from Sesotec
Guest Author Bio
Gargi Garach is a Toronto-based writer and editor. She holds experience in writing for healthcare and pharmaceutical companies.