For the detection of foreign bodies in a pack, X-ray inspection systems offer the versatility to identify metal, plastic, glass, stone and hard rubber down to very small sizes. In addition, they have the flexibility to check for quality issues such as missing items or deformed or broken products.
Again, where they are positioned on the line will be important. For many quality checks, the system will need to X-ray the complete pack. However, in some applications, monitoring of individual components can be beneficial. For a retorted ready meal, where various ingredients are added individually, by X-raying the key ingredient streams separately, the cost of any discovered contamination will only affect that single ingredient; if the pack is only inspected after all the ingredients have been added and the meal cooked, the entire contents will be wasted, and there will be further additional costs in the wasted packaging and the energy expended in the cooking.
To minimise food spoilage, a well-packaged product will help to maintain freshness and deliver the longest shelf life, be that for a tray, bag or pouch. The use of gas flushing in tray sealers creates MAP packs (modified atmosphere packs) that help to preserve fresh foods. New technologies are also being introduced, such as skin packing for meat and fish where the tray film is placed tightly around the product to prevent any air getting to it. This delivers extended shelf life without the need for gases.
It is, nevertheless, extremely important that the integrity of these packs is also monitored. This is particularly vital in today’s automated operations with little human intervention to spot a problem, for example if product has been trapped in the seal. In addition, tiny holes in a film will not be visible to the naked eye but are enough to let air in and cause early product deterioration.
For effective inspection of each pack, seal testers ensure the integrity of top sealed, thermoformed, flow-wrapped or lidded trays in different materials and sizes by applying controlled pressure to each pack going across a conveyor in order to detect any unwanted ‘give’. In addition, a recent innovation in the field of in-line leak detection is the use of laser technology which enables leaks of CO2 from holes as small as 0.25mm in MAP packs to be ‘’sniffed out’’ directly on the line, without stopping production and at an impressive speed of 180 packs per minute.
As the testing process is very gentle, both of these technologies further minimise food waste, so that product can be saved and re-packed.
Mis-labelling can be another cause for a product recall. As part of tray sealing checks, vision systems are able to verify the accuracy of a label, ensure that it is positioned correctly and relate the overprinted data to a company’s information systems to check that dates, weights, prices and barcodes are present, correct, legible and in the place they should be.
This information can also form part of a comprehensive traceability system. In the event of a problem, a single number on the pack can identify all the relevant information about the product. Data such as the gas mix, X-ray checks, checkweigher and vision system results, and even the crate it was packed in, can all be easily accessed. This means that any recall can be extremely focused, minimising both costs and the potential damage to brand reputation in the eyes of the retailer and the consumer. Such detailed information also helps to counter and prevent any fraudulent claims.
The key priority for food manufacturers and processors will always be on maximising throughput and efficiencies to help businesses keep ahead in crowded and competitive markets. As part of this, effective quality control is vital to maintain brand reputation and be viewed as a reliable supplier. Investing in the best packaging equipment is critical to achieving this.
At the same time, every 30 minutes 74,000 tonnes of food is being lost. If the use of this equipment can also help to deliver a 1% saving in both consumer and food industry wastage, that would amount to an annual saving in food waste of 13 million tonnes.
That would deliver the perfect win-win situation.