Having effective metal fragment control in food processing lines is extremely important. We often encounter the assumption that by having metal detectors, magnetic separation equipment is not needed.
It is vital to know that this is not the case and that both magnets and metal detectors play a crucial role in food safety.
In years past, magnetic separation and metal detection were mainly for protection of machinery. Today, food safety is paramount. Protection of products, consumers, and brands has never been so important. It can be demonstrated that both high-grade rare earth magnets and efficient metal detectors are essential to satisfying today’s product security requirements in the food industry and greatly complement each other to ensure metal risks are significantly reduced.
Let’s have a look at the differences between metal detectors and magnets and why both are necessary.
A metal detector is important and reliable in indicating the presence of mild steel, stainless-steel, copper or brass nuts and bolts, washers, copper wire, aluminium foil, and other even larger non-ferrous contaminants.
However, stainless-steel fragments and wires of 0.12″/3 mm size and below are usually work hardened, which means such fragments can be extracted magnetically along with other contaminants such as magnetic stone – this is where magnetic separation equipment is essential to ensure maximum product security. Often tiny pieces of non-ferrous material are difficult to detect with a metal detector so adequate upstream magnet protection is often considered essential.
Additionally, certain shapes of stainless-steel pieces or fragments can make them difficult to detect at certain orientations as they pass through the aperture of the metal detectors. In practice, this can sometimes mean detection of only 0.12″/3 mm or larger particle size. This can mean fine wires or other dangerous smaller fragments remain in the outgoing products, and the risk of contamination, complaints and recalls remain high.
Even the most sensitive metal detectors cannot ensure that fine ferrous metal and fine magnetic fragments will be detected – without magnets installed, these contaminants can remain in the product and lead to recalls.
Without efficient magnets, larger pieces will be detected by the metal detectors, but excessive product rejection can occur. The causes of rejection in these circumstances are often difficult to locate in bags or bins of bulk product. Therefore, it is much better to extract ferrous and other magnetics first with efficient rare earth magnets conforming to the current HACCP International Magnet Standard.
In summary, installing high-intensity magnetic separation equipment upstream of high-sensitivity metal detectors and x-ray units is crucial, as both are important and complement each other so that a highly effective final result in risk reduction can be achieved.
Your next steps in ensuring your product is properly covered
- Check if your metal detector conforms to the relevant standards for metal detectors
- Review the current HACCP International Magnet Standard
- Ensure you have correct magnetic separation equipment and procedures in place in order to maintain food safety
- Have your magnets validated now and annually ongoing to ensure management of risk