Business Drivers for X-ray Inspection – Part 3

By Christy Draus, Marketing Manager at Eagle Product Inspection

22 July 2016

Product packaging, temperature and salinity considerations

There are many effective food inspection methods available for quality control. The decision on whether x-ray inspection is right for your production line is not one to be taken lightly. Eagle experts recognize this fact and have combined their years of experience in this blog series titled “5 Reasons to Invest in X-ray Inspection for Quality Assurance“. Part three of five explores how a product’s packaging material, temperature and salinity are key drivers to choose x-ray machines for food inspection.

Packaging that contains metal

In addition to providing unrivalled physical contamination detection in unpackaged and bulk food products, x-ray machines are available which are specifically designed to inspect packaged products, including those wrapped in foil or metallized film. Tall cartons, loaves of bread with metal ties, and meat chubs with metal clips are all ideal x-ray applications.

Products packed in metallized film packaging can usually be effectively inspected by metal detectors using low-frequency operation (depending on the film thickness), but this can lead to reductions in the level of achievable on-line sensitivity. In some cases, if the metallized film is particularly thick, it is preferable to inspect products prior to packing. By contrast, there is no measurable impact on detection levels using x-ray inspection systems.

Aluminum foil packaging

Aluminium packaging, such as foil wraps and product trays, is a bigger problem for metal detection equipment. Detectors using balanced coil technology are unable to inspect products in aluminium packaging so a different technology, known as ’ferrous-in-foil’ detection, must be used.

X-ray will usually provide the best method of inspection when products are packed in aluminium foil. This is because metal detectors struggle to spot contaminants within aluminium foil packaging, while x-ray inspection can see straight through the low-density foil, ensuring a better view of contaminants such as metal, glass, mineral stone and calcified bone within.

Product temperature and salinity

Product temperature and salinity can both vary during the production process. Variations in temperature have no effect on sensitivity of detection via x-ray inspection. On lines where product temperatures vary, x-ray systems remain stable and maintain a high tolerance on achievable levels of contaminant detection.

Some food inspection systems such as metal detectors are affected by changes in product temperature (and subsequently generate many false rejects). However, x-ray systems with advanced image analysis software generate the absolute minimum of false rejects, which offers increased line efficiencies.

Variations in moisture content also have little or no effect on sensitivity of detection via x-ray inspection. By contrast, this is problematic for other food inspection systems, since they typically work on the principles of conductivity.

Many food products, especially salty or acidic ones, or those with a high moisture content, are conductive. When they pass through a metal detector, they can create a disturbance of the detection field. These signals referred to as a ‘product effect’ can be largely eliminated through the use of software algorithms and selection of the correct operating frequency. X-ray machines are not affected by salinity and can therefore better detect and reject contaminants in your food products before they reach your customers, protecting your business from costly product recalls.