Metal is one of the most commonly found contaminants in food products. Any metal that is introduced during the production process or is present in raw materials,
can cause production downtime, serious injuries to consumers or damage other production equipment. The consequences can be serious and can include costly
compensation claims and product recalls that damage brand reputation.
The most effective way to eliminate the chances of contamination is to prevent metal from entering the product destined for consumer consumption in the first place.
Metal contamination sources can be numerous, so it is important to implement a well-designed automated inspection program. Before you develop any preventive
measures, it is essential to have an understanding of the ways metal contamination can occur in food product and recognize some of the major sources of contamination.
Raw materials in food production
Typical examples include metal tags and lead shot in meat, wire in wheat, screen wire in powder material, tractor parts in vegetables, hooks in fish, staples and wire
strapping from material containers. Food manufacturers should work with trustworthy raw material suppliers who clearly outline their detection sensitivity standards to
support final product quality.
Introduced by employees
Personal effects such as buttons, pens, jewellery, coins, keys, hair-clips, pins, paper clips, etc. can be accidently added to the process. Operational consumables like rubber
gloves and ear protection also present contamination risks, particularly, if there are ineffective working practices. A good tip is to use only pens, bandages and other
ancillary items that are detectable with a metal detector. That way, a lost item can be found and removed before packaged products leave the facility.
The Introduction of “Good Manufacturing Practices” (GMP) as a set of strategies to reduce the risk of metal contamination is a worthwhile consideration.
Maintenance taking place on or near the production line
Screwdrivers and similar tools, swarf, copper wire off-cuts (following electrical repairs), metal shavings from pipe repair, sieve wire, broken cutting blades, etc. can carry
contamination risks.
This risk is significantly reduced when a manufacturer follows “Good Engineering Practices” (GEP). Examples of GEP include performing engineering work such as
welding and drilling outside the production area and in a separate workshop, whenever possible. When repairs must be made on the production floor, an enclosed
toolbox should be used to hold tools and spare parts. Any piece missing from machinery, such as a nut or bolt, should be accounted for and repairs should be carried out promptly.
In-plant processing
Crushers, mixers, blenders, slicers and transport systems, broken screens, metal slivers from milling machines, and foil from reclaimed products can all act as sources of
metal contamination. The danger of metal contamination exists every time a product is handled or passes through a process.
Follow Good Manufacturing Practices
The above practices are essential to identify the likely source of contamination. Good working practices can help minimize the likelihood of metal contaminants entering
the production flow. However, some food safety problems may be better addressed by a Hazard Analysis and Critical Control Point (HACCP) plan in addition to GMPs.
This becomes a vitally important stage in developing a successful overall metal detection program to support product quality.