Inspection Technology: Food For Thought

Sunday, December 15th, 2019

Concerted efforts are being made to reduce food waste throughout the entire supply chain. Mettler-Toledo explains how product inspection technology can be used to support these endeavours, with technology able to maximise yield from raw ingredients, reduce false rejects and ensure correct weight and fill.

Food waste is a global scandal on an astonishing scale. At present, around one third of all food produced for human consumption—approximately 1.3 billion tonnes—is either lost or thrown away every year. And it’s not just a matter of profligacy: food waste also inflicts an enormous environmental toll, creating an unsustainable drain on natural resources such as water, land and energy. Food waste, in short, is a tremendous problem that urgently needs to be addressed.

Politicians are, at last, starting to take note: countries such as Australia, Norway and France, among others, have been investing in food waste reduction strategies, and in some cases, legislating to prevent unsold food from being thrown away. In the UK, meanwhile, the government has announced a £15 million pilot project to understand why surplus food is not redistributed, before implementing a scheme to be launched in 2019/20 aimed at cutting waste in the most effective means possible. Top-level political pressure is mounting to do something about the problem, and fast.

So where does most food waste come from? According to the Food and Agriculture Organisation of the United Nations (FAO), in most medium- and high-income countries food is wasted and lost mainly at later stages in the supply chain, with the behaviour of consumers playing a huge role. At retail level, for instance, large quantities of food are wasted due to quality standards that over-emphasise appearance. The FAO says raising awareness of the beneficial use for food that is presently thrown away is crucial to reducing the amount of loss and waste.

But it’s not just a retail issue. To fully tackle the problem of food waste, companies and organisations at all stages in the supply chain need to play a more active role. Food waste isn’t only about picky consumers—it’s about reducing losses on farms, during the production and packaging process, and along the many points of distribution. It is a problem that requires combined and sustained efforts from everyone across the industry.

Identifying Food Waste

Increasingly, then, many food manufacturers and packagers are looking at ways of reducing food loss and waste. And there’s not just ethical and environmental reasons for doing so: cutting food waste on the production line means reducing costs and increasing profits. It also helps encourage a wider ethos of operational efficiency, as part of lean principles.

So, what are the primary causes of food waste inside food production and packaging plants? Surprisingly, there are numerous ways that it can occur. Perhaps one of the most common sources is false rejection—when a ‘good’ product is erroneously discarded from a production line during safety and quality inspection. Inaccurate weighing can also lead to underfilling, which results in product rejection by the retailer, or over-filling, which results in product giveaway. Contamination detection, meanwhile, may result in the rejection of a whole batch rather than the contaminated product alone, or wastage where a false reading indicates contamination where none is present. In addition, wastage can be caused by inaccurate labelling, damaged packaging, closure errors or missing items, all of which can trigger costly product recalls and disposal.

Process Of Elimination

Fortunately, help is at hand. Food manufacturers and packagers invest in product inspection technologies such as metal detection, x-ray, vision systems and checkweighers to help reduce food loss and waste. Often, it is a combination of these technologies that deliver the highest levels of operational efficiency, ensuring products meet regulatory and brand standards, and thus preventing rejections or recalls.

Even though every food production facility is different, there are some general best-practice approaches to food waste that food manufacturers can apply. Integrating contamination detection technologies early in the production process will remove any ingredients containing unwanted foreign bodies. This protects downline processing equipment and ensures contaminants are removed before additional value is added. Where contaminants are detected early, there is also more potential to re-work ingredients. This can in turn help in minimising food waste and associated costs.

False rejection needs to be reduced or ideally eliminated, but the wide product variation in a typical food production environment means this is no easy task. It is vital that contamination detection technologies such as x-ray and metal detection are adjusted correctly so only non-conforming products are rejected and no ‘good’ product is discarded from the line. This is achieved through regularly testing detection sensitivity levels and by making the most of fully automated product-set up and changeovers, which ensures detection sensitivity is always at optimum level, regardless of whether food is being processed as bulk, pumped or packaged product. Advances in metal detection technology promise to virtually eliminate false rejects from certain production lines, while some x-ray systems now combine fully automated product set-up with an optimum power generator and intelligent proprietary x-ray software to improve uptime, enhance detection sensitivity and minimise false rejection rates. So, it is worth investing in newer equipment to ensure ‘good’ product isn’t wasted.

Also, recent developments in product rejection mechanisms mean non-conforming products can now be removed with greater accuracy, reducing unnecessary waste on the line. Instead of removing a full belt width of product when a contaminant is detected, the latest x-ray systems use multi-lane scoop devices to accurately reject the area of the belt containing the contaminated product. Likewise, multi-lane air blast rejection devices can remove a smaller, more targeted section of product on the belt—limiting waste. In metal detection applications, meanwhile, advanced sealing technology used in gravity fall systems can now offer a dust-tight seal that reduces the chance of high value fine powders escaping into the reject channel.

Precision weighing is also an important technological component of reducing food waste. To comply with Weights & Measures legislation and prevent recalls, each product must be equal to or within tolerance of the weight stated on the label. Any underfilled products detected before leaving the line can be reworked, thereby avoiding waste. The flipside of this is that manufacturers can also prevent costly giveaway. Accuracy is everything, therefore, and inline checkweighers can be calibrated to exacting customer specifications, with automatic feedback to the filler control. If the raw product is very expensive, such as caviar for example, manufacturers want to ensure waste is avoided down to the last gram.

Filling And Labelling Accuracy

Product inspection technologies can also be used for assessing under- and over-filling, depending on the application. For example, x-ray systems can be used to perform zoned mass measurement and fill level inspection, such as highlighting if one compartment is under and another is over-filled in a two-compartment ready meal. Checkweighers, in isolation, can accurately measure the combined weight, but x-ray provides a more specific result for different parts within one packaged product.

Vision inspection technologies can perform numerous quality assurance checks, including inspecting fill levels and closures: such as identifying missing caps, trapped product under the seal or verifying tamper-proof seals.

Verifying the accuracy of the label, including its position and content—such as allergen declarations—will also avoid unnecessary product recalls. Vision systems inspect each label in real-time, based on established parameters such as lot numbers, bar codes, and use-by dates. Accurate use-by dates also help to avoid unnecessary wastage for the manufacturer, retailer and consumer.

Non-conforming packaged or unpackaged food detected during the processing phase can be reworked, which reduces wastage and costs. In addition, integrity inspections such as checking fill levels and seal integrity remove the risk of spoilage occurring during the distribution and storage stages, further reducing unnecessary waste.

Future Developments

Looking to the future, there are some emerging technologies and trends that will play an important role in reducing food waste. Metal detectors, x-ray systems, vision systems and checkweighers are becoming increasingly digital and connected, with increased data collection underpinning even higher accuracy around false rejection and fill levels. And in the longer term, blockchain holds real potential in the food sector as a means of providing greater trust and visibility in the farm-to-fork food chain, allowing specific products to be traced at any given time. This could prove a highly-effective means of helping to reduce food waste. Blockchain is also being trialled as a method of connecting retail businesses with local charities, to facilitate delivery of unsold food.

Whatever the future holds, product inspection companies are ready to support the food industry in its efforts to become more sustainable. Mettler-Toledo is perhaps better placed than most, in being the only manufacturer whose portfolio includes all four inspection technologies: x-ray, metal detection, checkweighing and vision inspection. As all our systems are designed and manufactured in-house, we also have the ability to customise solutions in order to meet specific requirements, making them ideally suited to customer efforts to drive out food waste.


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