Overcoming Snack Food Inspection Challenges with X-ray

Food & Beverage
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Sweet and savory snacks are growing in popularity and diversity across the globe. Half of all US consumers now snack at least twice a day[i] and snack foods eaten at main meals are projected to grow five percent over the next five years or to 86.4 billion eatings in 2018[ii].

This article explores why you need to invest in x-ray inspection if you want to increase revenue by expanding your business to international markets or major retailers.

With such an array of snacks on the market, manufacturers are increasingly reliant on food inspection equipment to eliminate the risk of costly product recalls, safeguard their brand reputations and protect consumers from harmful physical contaminants and quality defects.

However, many snack applications can prove challenging for traditional inspection equipment. This article explains how x-ray food inspection systems can overcome such challenges to ensure the safety and consistent quality of a wide range of loose and packaged products, including extruded snacks, crisps, dried fruit, nuts, seeds and popcorn.

The main challenges snack manufacturers face can be summarized as follows:

High Salt Content of Products

Many snack foods, including potato chips and nuts, contain high doses of salt and are therefore conductive. When they pass through a metal detector, they can create a disturbance of the detection field, triggering false rejects.

By contrast, x-ray inspection machines are not affected by salinity, and are capable of detecting a wide range of physical contaminants, including metal, glass, mineral stone, calcified bone and high-density plastic and rubber, as well as enhancing consumer satisfaction by identifying seasoning agglomerates such as flavor or powder lumps.

Additionally, unlike traditional inspection systems, variations in product temperature and moisture content have no effect on sensitivity of detection via x-ray inspection. On snack food lines where product temperatures may vary, x-ray systems remain stable and maintain a high tolerance on achievable levels of detection.

Metalized Film and/or Foil Packaging

Many snack products, such as energy bars, are packaged in metalized film or foil packaging. Although these products can usually be effectively inspected by metal detectors using low-frequency operation, this can lead to reductions in the level of achievable on-line sensitivity. In some cases, if the metalized film is particularly thick, it’s preferable to inspect products prior to packing.

By contrast, there’s no measurable impact on detection levels using x-ray food inspection systems. As well as providing unrivalled detection of physical contaminants in bulk (loose) foods, x-ray inspection machines are available which are specifically designed to inspect a wide range of packaged products, including those wrapped in foil or metalized film.

What’s more, while metal detectors struggle to spot physical contaminants in products packaged in aluminium foil, x-ray inspection can see straight through the low-density foil, ensuring a better view of any metal contaminants within.

Quality Control

Many snack food lines require high throughputs and maintaining optimum inspection levels whilst ensuring products look and perform exactly as consumers expect can be a challenging task for manufacturers. In addition, shrinking profit margins are forcing many food processors to look for process efficiencies.

Market-leading x-ray equipment can provide safety and quality assurance at every stage of production for bulk, packaged and unpackaged applications by carrying out a number of quality checks commonly associated with checkweighers and vision systems.

Mass measurement

X-ray food inspection systems can help snack food manufacturers exert better quality control by measuring overall and zoned mass. X-ray mass measurement is particularly effective for food inspection on high-speed lines where traditional in-line weighing systems may not be practical or offer the same level of accuracy. It’s also useful when space limitations mean manufacturers can’t accommodate separate contaminant detection and checkweighing devices. For products presented in defined compartments, advanced x-ray systems can provide results for each individual zone/compartment.

Unlike checkweighers, which can only measure total weight, x-ray inspection machines are available that are not only capable of determining the total weight of a box of snack bars, but also checking inside sealed products to differentiate the contents from the packaging, and weighing each individual snack bar.

Component counts
Like vision systems, x-ray inspection machines are simultaneously capable of detecting missing, deformed or broken food items.

Market-leadingx-ray systems can look inside final sealed packaging to check that all components are present, for example that the right number of cereal bars are inside each box. They can count products and components that can’t be seen or counted by cameras or human eyesight.

Package integrity

The integrity of air-tight seals is a vital quality control issue for snack food manufacturers. The freshness of many snacks depends on their seals, but these can be easily compromised by bits of food getting trapped or physical contaminants. X-ray inspection systems are capable of preventing food spoilage by identifying particles as small as 1 mm caught in seal areas.

Fill level inspection

Maintaining the correct fill level of a product is a constant challenge in food manufacturing. Overfills and underfills have an effect on costs, as well as consumer satisfaction.

Modern x-ray food inspection systems allow manufacturers to set maximum and minimum fill levels and will reject products that fall outside these. Fill levels can also be adjusted by adding an optional feedback to the filling machine, which is particularly beneficial for staged products, such as cans of crisps. Filler feedback control can also play a key role in reducing product giveaway.

Variations in Product Density

Many snack foods, including bags of trail mix and granola bars, contain high variations in density. Finding physical contaminants in these types of products can prove challenging for traditional x-ray inspection systems as the varying densities create ‘busy’ x-ray images.

X-ray systems equipped with dual energy x-ray technology such as Material Discrimination X-ray (MDX) provide advanced image processing and deliver enhanced contaminant detection based on a material’s atomic number and not on density alone.

MDX enables the detection of historically difficult to detect physical contaminants, such as flat glass or low-density plastics, rubber, stones and rocks, in multiple-textured products. In addition, the technology allows food processors to inspect products in popular packaging designs, such as fold-out cardboard sandwich packaging and corrugated card encasements that plague traditional x-ray inspection tools.

An MDX system installed at a critical control point (CCP) can help snack processors increase production uptime, as well as reduce maintenance and repair costs of downstream processing equipment by removing physical contaminants prior to processing.

In addition, multiple reject lanes that can independently evaluate and remove contaminants in bulk products can help to increase yields and process efficiencies by reducing the amount of rejected products and rework to a fraction of the amount of conventional sweeper rejecters.

Market-leading x-ray food inspection systems are also equipped with barcode readers which, by lifting product data directly from labels, allow products to be identified and x-ray equipment to automatically change its inspection criteria to match individual products. Barcode readers enable manufacturers to inspect multiple types of snacks on the same production line and can increase production uptime by enabling quick product changeovers.

SQF Compliance

Snack manufacturers face increasing pressure to achieve SQF compliance. As well as helping manufacturers meet Hazard Analysis and Critical Control Points (HACCP) regulations, x-ray inspection equipment can help them achieve certification to a number of Global Food Safety Initiative (GFSI)-recognized schemes, including Safe Quality Food (SQF) 2000 Code, which is achieved through a successful third party audit.

Market-leading x-ray food inspection systems can help snack processors meet the rigorous requirements necessary to achieve SQF certification by incorporating features like validation mode for unique login credentials and XML files for data storage that will help to support their audit process.


Snack manufacturers face many challenges, from maximizing output and enhancing production processes, to minimizing the risk of brand-damaging product recalls and complying with strict regulations and industry standards. Installing the right food inspection equipment can help manufacturers overcome these challenges.

Unlike traditional inspection systems, x-ray food inspection systems are not fazed by salty snack foods and can detect a wide range of physical contaminants, irrespective of their size, shape or location, within loose and packaged applications, including products wrapped in metalized film and/or foil.

What’s more, the ability of x-ray inspection machines to perform additional inline quality checks eliminates the need for multiple machines on a production line and can help to save valuable floor space and boost productivity.

For snack foods with high variations in density, such as nuts, dual-energy MDX technology provides unprecedented contamination detection capabilities. And, last but not least, investing in a market-leading x-ray system can help processors achieve SQF compliance, which is vital to keep pace in today’s highly-competitive and diverse snack food industry.

[i] https://blogs.technomic.com/impulse-snacking-across-the-u-s-infographic/ 

[ii] http://www.preparedfoods.com/articles/114427-snack-food-consumption-to-increase

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