For example, wayward golf balls do land in fields where potatoes are being grown causing them to become an unwanted addition to the harvest.
During processing, standard x-ray technology is unable to consistently discern between spherical golf balls and similarly shaped potatoes.
Needless to say food manufacturers need to ensure that there is no risk that golf balls or any other foreign contaminant will make its way into the downstream production process and into the potato products sold to the consumer.
Consumer life style
Consumers are seeking convenience from their food, to make it fit better with increasingly busy and mobile life styles.
This means that consumption of pre-packed fruit and salads and ready-made meals is rising, while snacking products such as packs of nuts and seeds, and breakfast cereals are also very popular.
In food inspection terms, these products provide challenges, due to the complex, variable density of the foodstuffs and also sometimes the innovative packaging they come in.
Stones in potatoes, salads, dry fruit and vegetables are common contaminants; rice products are regularly contaminated by stones and glass.
Conventional x-ray inspection technology is excellent at detecting stainless steel, ferrous and non-ferrous metals, glass, calcified bone, mineral stone, and high density plastics and rubber in a food product and rejected accordingly.
However, conventional x-ray technology has difficulties detecting inorganic contaminants such as glass shards, low density plastics and rubber, or stones and rocks, when present within a complex density product i.e. with high variations in density, such as a pre-packed salad.
Typically, the image produced by conventional x-ray technology is crowded and indecipherable.
Clearly, this is a problem for food manufacturers, even more so in an age when consumers are increasingly conscious of food standards issues.
Brand reputations are at stake and no manufacturer wants to endure the embarrassment, not to mention the short- and long-term costs, of a product recall due to contamination of food by objects that should have been removed before reaching the supermarket shelves.
Eagle explains MDX
It is for this reason, that Eagle Product Inspection has harnessed its Material Discrimination X-ray technology, or MDX, for use by food manufacturers.
MDX is an x-ray technology that can discriminate between high and low x-ray channels. When x-rays are directed onto a food product, a proportion of the x-ray energy is absorbed by the product, depending on the product’s composition, while the rest of the energy passes through to a detector.
Each ingredient in a product has its own atomic number, and the higher the atomic number, the greater proportion of x-ray energy is absorbed.
MDX has a detector array that gives values at two different energies and a relative ratio of energy absorbed can be calculated to determine a material’s composition.
Foreign body detection becomes based on chemical composition i.e. atomic number rather than just density variation or product thickness.
MDX can detect flat glass and stone in mixed nuts, for example, which conventional x-ray finds very challenging.
Innovative packaging designs such as fold-out cardboard sandwich packaging and corrugated card encasements provide challenges in foreign body detection for standard x-ray inspection technology.
The development of MDX for product inspection has followed the demands of food manufacturers that need a reliable solution to detect and remove contaminants irrelevant of product type or packaging format.
Looking to the Future
There are potential future uses for MDX beyond that of the inspection of complex density food products. For instance, the technology might be used to measure ingredients to simplify the classification of products for food labelling.
What is certain is that with modern lifestyles calling for ever greater convenience in food consumption (and indeed you might argue while golf courses are being situated close to potato fields), the issues of contamination and complexity in the food production chain are not going to go away.
The consumer needs to feel confident that every effort is being made to ensure that only high quality produce makes it into the supermarket, and the damage to a brand through failing to meet these exacting standards is something that food manufacturers can ill afford.
- Kyle Thomas, strategic business unit (SBU) manager at Eagle Product Inspection, is responsible for research and development and product portfolio expansion to meet the demands of the food and beverage manufacturing and processing market.