Inspection Methods for Snack Foods

Global snack sales totalled $374 billion annually ending March 2014—an increase of 2 percent year-on-year. That’s because more consumers are snacking today than ever before and snacking more frequently. In fact, it’s estimated that on average, 24 percent of our daily calorie intake comes from snacks. With nearly one in four calories consumed outside a meal, the snack is no longer just a treat; it’s become a fourth meal.

As public scrutiny of food manufacturers continues to escalate and consumers increasingly turn to social media to voice complaints, snack processors have become more reliant on food inspection equipment to protect consumers and reduce the risk of brand-damaging product recalls in order to stay ahead of their rivals.

However, many snack applications can prove challenging for traditional product inspection equipment.

Why Are Snacks Such a Challenge to Inspect?
The unique challenges manufacturers face when striving to produce safe and quality-assured snacks can be summarized in the following issues.

Variety of potential contaminants. Often snacks contain a wide variety of ingredients that are all open to different types of contaminants. Fruits, vegetables, and nuts may be contaminated with stones or a piece of wire from the farm, while dairy products can be suspect to metal or plastics from processing.

High salt content of products. Many snacks, such as nuts and potato chips, contain high doses of salt and are conductive. When they pass through a metal detector, they can create a disturbance of the detection field, triggering false rejects. Product temperature and moisture content can also affect a metal detector’s detection sensitivity.

Metal packaging. Metalized film and foil are used to package various snacks, including energy bars and chocolate. Inspecting these products using metal detectors can lead to reductions in the level of achievable sensitivity. In some cases, if the metalized film is especially thick, it’s preferable to inspect products before packing.

Variations in product density. Many snacks, such as bags of trail mix and granola bars, contain high variations in density because of the multitude of ingredients. Finding physical contaminants in these products can prove challenging for traditional X-ray inspection systems as the varying densities create “busy” X-ray images.

Contaminants similar to product. Color and hand sorting are frequently used to remove rocks and other visual defects from loose flow bulk snacks foods, such as almonds, but neither method is entirely accurate as stones are similar in shape and color to the product. Visual inspection methods are also limited to the top layer, which means anything that can’t be seen, won’t be identified or removed.

Quality assurance. Proper portioning and seal integrity are another two major concerns for snack manufacturers. Individual bars and boxes with multiple bars can be underweight, overweight, deformed, or broken. Additionally, during the sealing process, bits of food can get trapped in product seals, creating a faulty seal and causing food spoilage. To overcome such issues, manufacturers have traditionally installed a range of inspection equipment on their production lines, including checkweighers, metal detectors, and vision systems.

Metal Detection vs. X-ray Inspection
Different snacks and packaging types require different product inspection solutions and selecting the right system is crucial to guarantee maximum detection sensitivity and high throughput.

In many cases, there’s only one suitable solution (metal detection or X-ray inspection) and in many others, either technology could be used. Occasions also exist where it may be necessary to install both technologies at different Critical Control Points (CCPs) on the same line.

Metal detection. For cost-effectiveness, metal detectors usually offer the best solution when looking to detect ferrous and non-ferrous metal, stainless steel, and aluminium contaminants. A metal detection search head also takes up less space than an X-ray inspection system. This means that for applications where installation space is limited and metal is the only likely contaminant, a metal detector may be the best option.

X-ray inspection. These systems are just as adept as metal detectors at finding metal and provide detection of non-metallic contaminants too, including glass, mineral stone, calcified bone, and high-density plastics.

In addition, the latest X-ray inspection equipment is simultaneously capable of performing additional quality assurance checks such as measuring mass, checking fill levels, and detecting missing and damaged products, as well as identifying seasoning agglomerates such as flavor or powder lumps.

Unlike with traditional inspection systems, the accuracy of X-ray food inspection equipment isn’t affected by freeze/thaw conditions, moisture, or salinity, and metal packaging has no effect on sensitivity of detection.

In addition, duel energy X-ray technology, Material Discrimination X-ray (MDX) for example, can discriminate materials by their atomic number and not on density alone to enhance traditional X-ray inspection and enable the detection of those historically undetectable inorganic contaminants in multiple-textured products. MDX also allows snack manufacturers to inspect products in corrugated card encasements and foldout cardboard sandwich packaging that plague traditional X-ray inspection tools, and is especially valuable for inspecting snacks with high-density variations, such as cereals, nuts, and confectionery.

Benefits of X-ray Inspection
Advanced X-ray food inspection equipment is capable of providing safety and quality assurance at every stage of production for unpackaged and packaged snack applications, and eliminates the need for multiple inspection machines on one line by performing the following quality checks.

Fill level. Modern X-ray inspection systems allow manufacturers to set maximum and minimum fill levels and will reject products that fall outside these pre-set parameters. 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 reduce product giveaway and customer complaints by assuring the customer receives exactly what they expect every time.

Component counts. X-ray inspection equipment is simultaneously capable of detecting missing, deformed, or broken snacks. Some x-ray food inspection 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. By counting cookies and crackers that can’t be seen or counted by cameras or human eyesight, systems can help to reduce customer complaints.

Seal integrity. The integrity of airtight seals is vital to the quality control of food produce. X-ray machines are capable of preventing food spoilage by identifying obstructions in packaging seals. Ensuring seal integrity is an important step in the prevention of microbiological contamination and any resulting product recall this could cause. Seal integrity checks by X-ray inspection machines can help prevent customers rejecting a spoiled product or sticky packaging.

Mass measurement. X-ray food inspection systems can help snack manufacturers exert better quality control by measuring overall and zoned mass. Mass measurement is particularly effective 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 machines and need all checks to be simultaneously carried out—in one machine. For products in defined compartments, X-ray inspection systems are available that can provide results for individual zones.

Unlike checkweighers, which can only measure the total weight of a box of snack bars, X-ray inspection equipment can measure the weight of a box of snack bars and the weight of each individual snack bar inside the box.

Ever-Increasing Regulations
Following a number of highly-publicized food safety scandals in recent years, global safety regulations are increasingly far-reaching and more stringent. Examples include the Food Safety Modernization Act, or FSMA, which aims to ensure the U.S. food supply is safe by shifting the focus from responding to contamination to preventing it, and China’s revamped food safety law, which took effect in October 2015, and imposes criminal liability for unsafe food.

On top of this, snack manufacturers in the U.S. face increasing pressure to achieve Safe Quality Food (SQF) compliance. Some X-ray food inspection systems can help manufacturers meet the rigorous requirements necessary to achieve SQF certification with features like validation mode for unique login credentials and XML files for data storage that support manufacturers’ audit processes.

Product inspection equipment can also help manufacturers comply with Hazard Analysis and Critical Control Points principles, as well as achieve certification to the following Global Food Safety Initiative-recognized schemes:

• The British Retail Consortium, or BRC, Global Standard for Food Safety;
• International Featured Standard, or IFS; and
• ISO 22000:2005.

Furthermore, systems can assist manufacturers in complying with national food safety regulations and retailers’ own codes of practice.

Data is King—Traceability and Reports
The ability to swiftly identify and isolate unsafe food is crucial to ensure snack safety and avoid product recalls.

The latest X-ray inspection equipment can improve product traceability by recording valuable production data and machine status information, and enabling quick and easy access to it. Systems store images of all rejected packs, which are date and time stamped with the product name and can be taken off the X-ray machine and stored on a manufacturer’s computer in chronological order. These offer traceability on any complaints or returns as the production times/codes can be immediately cross-referenced.

By recording large amounts of useful information, X-ray machines can also help to identify trends and instigate preventive action to reduce the occurrence of contamination.

What’s more, in the event of a legal claim, X-ray food inspection equipment can help manufacturers provide a due diligence defense by demonstrating that they took all reasonable, practicable steps throughout the manufacturing process to avoid the breach of food safety regulations.

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Draus, marketing manager at Eagle Product Inspection, has over 12 years of experience and a diversified skill set in business-to-business environments. Reach her at [email protected].