X-ray product inspection machines have evolved greatly over the years. Modern x-ray machines can detect a wide range of contaminants based on their density or chemical makeup. Additionally, x-ray inspection machines can check package weight, seals and fill level to make sure the package is ready for distribution.
However, as useful and powerful as x-ray inspection machines are, they aren’t perfect. Even newer x-ray machines with Dual Energy X-ray Absorptiometry (DEXA) or Material Discrimination (MDX) technology can miss some contaminants.
What Contaminants Are X-Ray Systems Most Likely to Miss?
Generally speaking, exceptionally small or low-density objects are the most likely to be missed by an x-ray inspection machine.
Things like hair, fine string, Band-Aids, insect parts and some organic compounds may be missed by even the most powerful and sophisticated x-ray systems. Super-small low-density metal shards (such as aluminum) may also be missed by an x-ray scan.
Why Might X-Ray Scans Miss These Items
Older x-ray systems may miss most of these items because their density is too low to show up on a grayscale x-ray image.
Newer x-ray systems that use two x-ray emitters are significantly better at identifying low density objects because they use both high and low frequency x-rays. Yet, sufficiently small or low-density objects may still be missed.
Organic compounds are tricky to detect via x-ray. Some compounds may be distinguishable if you’re using an MDX or DEXA system, but compounds with a chemical makeup similar to the food being scanned will be difficult to identify.
Oddly enough, metalized packaging rarely has a significant effect on the accuracy of an x-ray inspection machine—unless the metal is thick enough to completely block out the x-ray, it’s still possible to distinguish between a dense contaminant and the packaging.
Dealing with Easy-to-Miss Contaminants
Thankfully of the most common contaminants that x-ray inspection might miss are easily controllable by you.
Common countermeasures include:
- Hair. Following basic food industry standards regarding the use of hair nets and proper grooming among employees working on the production floor near food and processing equipment is the best way to limit this contaminant.
- Fine string. There are many ways a piece of string may be introduced into your food packages. One possible source is frayed sewing lines in work uniforms. Another would be any equipment in the factory that manipulates string for packaging/food prep purposes. Inspecting work uniforms for wear, keeping work and rest areas clean, and routinely checking processing equipment can help minimize this risk factor.
- Low-density plastics. Newer DEXA and MDX systems can detect most plastics without issue. However, some low-density plastics may escape detection. The best solution is to use detectable plastic components when possible, and to remove low-density plastics from the production area.
As always, running a comprehensive hazard analysis is key for preventing the worst contamination risks.
Keeping your products and customers safe is easier when you have a plan!