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How x-ray's versatility can protect product quality and brand reputation in the biscuit sector

How x-ray's versatility can protect product quality and brand reputation in the biscuit sector

The market for bakery and biscuits remains buoyant. Even with growing consumer awareness regarding health and diet and the need to limit the intake of sugary items, the occasional ‘treat’ of a delicious biscuit is still something to be savoured and enjoyed!


At the same time, manufacturers are taking note of changing consumer attitudes with the development of healthy and low sugar varieties, alongside other new flavours, tastes and shapes. For these reasons, according to Morder Intelligence, the global biscuits market is expected to reach USD 125 billion by 2022 at a CAGR of 3.7%.

Biscuits are universally popular but different countries and regions have their own favourites, everything from chocolate digestives and custard creams in the UK, to sugar-glazed puff pastry specialities in Belgium, and chocolate-covered sweet cottage cheese bars in Russia. 

However, whatever the brand, whatever the recipe, one of the critical factors in enabling brands to establish and maintain popularity and market share in what are highly competitive markets is the consistent quality of their product. Brand reputation in any market is hard won and easily lost. Consumer trust and confidence can be seriously damaged by just one error or oversight. What’s more, the growth of social media means that consumers now have the opportunity easily and quickly to share any dissatisfaction with a large audience.

Retailers too are very conscious of their reputations with their customers and are setting increasingly high standards for their suppliers. The cost implications of any type of product quality issue can also be significant. Alongside the impact on sales and the loss of brand reputation, there are the practical costs such as large retailer fines and the logistics of any product recall.

For biscuit manufacturers therefore, the need to deliver product of a consistently high quality has never been more important.  At the same time, markets are becoming increasingly competitive, requiring companies to focus just as much on maximising efficiencies and throughput in their operations. Automation of many manufacturing and packing processes is helping them to achieve this but less human intervention on the line means fewer opportunities to pick up on something that has gone wrong.

All of this means the selection of the correct inspection equipment is an increasingly important factor in ensuring companies are able to maintain the highest quality standards. 

In terms of the need to prevent foreign bodies in products, biscuit manufacturing faces some particular challenges. The proliferation of new recipes has seen many biscuit varieties now incorporating a variety of additional ingredients such as dried fruits or nuts, which have an inherent risk of containing foreign bodies. This may require an initial checking of the incoming bulk raw material.

The sieving of flours provides an effective screening of foreign bodies but the sieves themselves can deteriorate over time, and there is always the risk of small components from the processing and packing machinery contaminating the product mix. This highlights the need for finished packs to be thoroughly inspected as well.


While metal detectors will provide a comprehensive screening of unwanted metal items in either bulk or final product, the technology does have some limitations. Many biscuit packs now use metal foil in order to maintain taste and extend shelf life, which limits the effectiveness of metal detection techniques.  Screening is therefore often carried out pre-packaging which does not give the closed pack a final integrity check.

At the same time, the risk of foreign bodies can extend beyond metal parts, particularly at the bulk product stage where, for example, stones or grit could still be present. And the production and packing process may involve product passing through machines that also contain plastic components. In these scenarios, it is the ability of x-ray inspection systems to spot a wider variety of foreign bodies that is leading to the technology being adopted for many biscuit and bakery applications.

X-ray inspection involves the projection of relatively low energy x-rays onto a sensor or detector. As the product or pack passes through the x-ray beam, only the residual energy reaches the sensor. Measurement of the difference in the absorption level of the X-ray energy between the product and a foreign body enables the foreign body to be detected.

It is important to stress the absolute safety of this inspection process. There is no risk of radiation contaminating either the food itself or a machine operator working in close proximity to the machine. In fact, levels of radiation that any line operator is likely to be exposed to are much lower than when flying in a plane.

Another key benefit of x-ray technology is its ability to work undeterred in even the harshest of environments, such as humid and temperature controlled atmospheres. In terms of packaging, a significant benefit is that foreign bodies can be detected through aluminium foil. X-ray inspection systems can also handle a wide variety of pack formats including top sealed and thermoformed trays and flexible bags as well as unpacked and bulk product.

Equally important, high quality biscuit producers are acutely aware that product quality is more than just the prevention of foreign bodies. As a treat or luxury item, the appearance of the product is an essential part of the consumer experience, particularly biscuits with a distinctive shape such as those aimed at children. A chipped or broken biscuit does not only mean a negative consumer experience, but can have a negative impact on brand image.

Here x-ray technology can demonstrate even greater versatility through its ability to spot these types of quality issues. It can detect broken, undersized or missing items in packs, as well as deformed product or packaging, or items with cracks or fissures. 

For missing items, a more traditional detection process might be through checkweighing which often already forms part of the packing line. However, in a variety biscuit box, the often substantial variation of the weights of the different biscuits can mean an entire stack of a very light item could be missing and still not be detectable by checkweighing. This can also apply to smaller packs, again in particular for lighter products such as wafers, if the process is not well controlled.

Similarly, in a pack of chocolate wafers, if one wafer is considerably over weight and the other considerably under, the total weight of the pack may still be correct but the consumer will not be satisfied with the overall pack contents.

Another important benefit of x-ray inspection in a world where consumers are more inclined to complain is its ability to offer full traceability. In the event of a complaint, data management systems linked to x-ray inspection and labelling can enable retrieval of the x-ray image of a particular pack, establishing beyond doubt whether or not there was a problem. The fact that every image is captured means false claims can be quickly rejected.

In selecting an x-ray system from the increasingly wide choice of models available today, it is important for manufacturers to carefully assess their requirements, taking into account areas such as the products to be inspected, the most frequent type of foreign bodies to be searched for, and the length and frequency of production runs.

One of the first considerations will be whether a single or dual energy machine is required.  A single energy inspection system uses one x-ray sensor to scan the product. This means there needs to be a reasonable variation in the density of the product and the foreign body in order for the machine to successfully identify it.

Dual energy systems use two x-ray sensors to generate two images and therefore a much better contrast, which enables them to more easily pick out low density foreign bodies. One area where this is of particular benefit is the ability to identify (low density) porous stones in nuts.

Many x-ray systems are also capable of finding much smaller foreign bodies than metal detection systems, for example down to 0.3mm in some instances. Advanced Genetic Algorithm technologies enable a machine to be trained to better identify specific objects.

However, sensitivity levels need to be applied with care. An over-sensitised x-ray machine may lead to exceptionally small fragments, which are harmless to the consumer, being identified. This can result in unnecessary product or packs being rejected – and potentially wasted – as well as increased line stoppages.

Companies should therefore discuss their specific requirements with a trusted supplier, and assess the equipment available in terms of its performance capabilities and cost of ownership to ensure the selected model can deliver the right levels of sensitivity, performance and efficiency. As part of this process, an element of future-proofing may also be worthwhile with a machine that has the ability to meet higher product quality standards that may be introduced in the future.

Bakery and biscuit manufacturers have long recognised that product quality is a vital element in their continued success. Nevertheless, in today’s highly competitive markets and an environment where problems can be more easily publicised and shared, the need to provide effective inline quality inspection has taken on even greater significance. 

The versatility of x-ray inspection can provide valuable support to companies and brand owners who are intent on maximising quality to enhance and protect their reputations.

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