Ensuring safety and quality in glass packaging

©Stepan Popov via 123RF

In Europe, for example, The European Container Glass Federation (FEVE) reported a recycling rate of 73% towards the end of 2015, enabling the container glass industry to reduce its environmental footprint dramatically by saving energy and raw materials.

From a brand perspective, glass gives a premium feel to a product and also allows consumers to get a clear view of the product within – adding considerably to shelf appeal. It is also nonporous and impermeable, so there is no interaction between glass packaging and the product within that will affect the flavour of food and beverages. Glass is the only packaging material that the U.S. Food and Drug Administration labels as GRAS: 'Generally Recognised as Safe', as there is no addition of chemicals during production.

Glass contamination

From a safety and quality perspective, regulations are very strict in the food sector, and legislation such as The Food Safety Modernization Act (FSMA), Hazard Analysis and Critical Control Points (HACCP) and the Global Food Safety Initiative (GFSI) have been implemented to safeguard manufacturers and consumers alike. A single shard of glass in a product could have devastating effects – both on the consumer and the brand reputation of the supplier company – therefore x-ray inspection systems are vital on production lines using glass, to ensure only clean, contaminant-free packages reach the retail supply chain.

Glass contamination can occur accidentally in many ways on a production line. There could be breakages during the cleaning process, breakages on the line because of conveyor vibrations or back pressure, or breakages during the filling process due to misaligned filling heads striking the top of containers. Over tightened containers can also cause breakages.

Glass is the most challenging packaging format to inspect, primarily because the main contaminant associated with it is glass itself – which is the same material density as the packaging. The size and shape of containers can add to the complexity of inspection, as the base, sidewalls and neck of containers can cause blind spots, where the packaging itself has the potential to mask a contaminant.

Unusually shaped containers can present themselves to the x-ray system in different orientations and have no fixed points, which can lead to false rejects as the x-ray image keeps changing. The product within can also cause what is known as ‘product effect’. Products with a high salt content – such as brined items, for example – can affect the level of x-ray absorption and system sensitivity, which may also lead to false rejects.

To overcome these challenges, x-ray systems have been designed and developed specifically for this application. X-ray is the only product inspection solution capable of detecting glass in glass containers and does so by measuring the differences in x-ray absorption throughout the container.

X-ray technology

The latest x-ray technology inspects all areas of a container by sending x-rays through the base area, while simultaneously inspecting through the sides. This provides all-round inspection and the crown of the container appears flat – meaning blind spots are effectively removed. The beam passes level with the shoulder of the container (below the threads and cap) and produces a far less complex image, enhancing detection capability. The angle of inspection also enables exceptional, full-height fill-level inspection at high speeds.

X-ray systems can be adjusted to suit a wide range of container sizes via full length guide rail systems. This ensures smooth product handling and repeatable product changeovers, which is vital to ensure productivity levels are kept to a maximum.

For manufacturers producing products in glass containers, x-ray systems are a must-have on production lines. There are a number of variables to take into consideration to achieve the optimum configuration, and by working with an expert partner it is possible to ensure that glass contaminants are detected and rejected effectively – safeguarding brand reputation and, most importantly, the safety of consumers.