X-ray food inspection technology is quality control at the highest level. Using the technology’s packaging-penetrating capabilities, quality controllers can identify the presence of foreign objects inside types of packaging, verify packaging fill levels, and confirm the product integrity of packaging for consumer safety. The technology is a reliable method critical for providing and ensuring food safety compliance, as well as production efficiency, in fast-paced food production lines.

With the ever-growing consumer demand for food products along with tightened food safety and regulatory standards, food manufacturers face significant operational and manufacturing challenges. Food recalls can be financially devastating to the bottom line, incur high operational costs, and tarnish a brand’s reputation. Therefore, food inspection systems must be integrated into the production line to mitigate the risk of contamination. Shortcomings of traditional inspection methods, especially for more modern flexible food packaging, have made X-ray food inspection the perfect solution for these more modern flexible food packages. Destructive testing and physical contact with packaged products are not required with X-ray inspection. This guide will focus on the technology’s X-ray inspection mechanisms, the industry’s X-ray inspection systems, and the X-ray inspection systems for the unique requirements of canned packaging lines.

What is X-Ray Food Inspection and How Does It Work?

Food inspection systems utilizing X-rays are built on the premise of measuring the degree of mass and the density of the product. Three primary elements make up the system: the X-ray generator, a linear diode array sensor, and an industrial computer processor.

A generator sends a low-energy X-ray beam to the conveyor belt, and each X-ray beam is focused on individual packaged products or raw materials. As the packages pass through the X-ray beam, the different materials of the packages absorb the X-ray energy, depending on the composition of the materials. As an example, more energy is absorbed by dense foreign matter, such as steel, glass, and stone, compared to the absorption of less dense materials, such as water, fat, and air.

There is a sensor that measures the energy of the X-ray beam that was able to pass through the package to detect potential contaminants. The computer processes the energy measurement and creates a grayscale image. For more detail, the image is constructed with dense materials displaying a dark coloration. The software implements sophisticated algorithms to evaluate the image within milliseconds to maintain strict quality standards. If the software finds a dark region indicating foreign material that is out of the acceptable baseline range, the software initiates the rejection mechanism to discard the product from the production process.

As opposed to a typical metal detection mechanism, this type of contaminant detection is much more advanced. Metal detectors read their surroundings by using electromagnetic fields. They rely on the foreign body to create a behavioral change in the electromagnetic field by creating a conductive or magnetic field. However, X-ray technology functions independently from electromagnetic fields and uses the presence or absence of foreign bodies to ‘see through’ obstructing materials, identifying a wide range of foreign objects.

X-ray technology can state a wide range of packaging designs, as it is density-driven, unlike other technologies that rely on measures of conductivity for a specific product.

Applications Across Different Food Sectors

Food industry segments demand varying degrees of quality assurance. As a result, line designers have to be precise in the type of inspection equipment needed to address specific potential hazards pertaining to each segment. The versatility of X-ray inspection systems means they work in most processing environments.

Meat and Poultry

Physical hazards are inherent in the processing of meat and poultry. These include the contamination of the meat with calcified bone fragments, broken stainless steel grinder blades, and hypodermic needles. In addition, raw meat has a high moisture and salt content. This results in a very strong “product effect” that causes most metal detectors to reject the meat. X-ray technology, however, ignores moisture and salt and accurately identifies bone and metal fragments.

Bakery and Snacks

To keep products fresh and keep moisture out, the bakery and snack sectors use metalized films and aluminum foils for their packaging. Once products have been packaged in these aluminum foils, conventional metal detectors cannot evaluate them. Energy from X-ray food inspection systems easily passes through metal. Because of this, X-ray detectors can find metal wires and stones (that can be found in nuts) even when the packaging is closed, preventing foreign material contaminants.

Canned and Packaged Goods: The Ultimate Challenge

X-ray technology is of great importance in the meat industry and the bakery industry, but for the canned food industry, it is necessary to uphold product quality. The most difficult goods for quality control engineering to deal with are canned and packaged goods. Quality control engineers encounter an absolute barrier when it comes to metal cans. With a metal cylinder, traditional methods of detection are completely ineffective against foreign contaminants. Therefore, in a canning factory, X-ray food inspection is not an optional add-on; it is a fundamental design imperative to avoid costly recalls. The rest of this guide will highlight the unique problems posed by canned packaging lines and demonstrate that X-ray technology is the ultimate answer to these problems.

X-Ray vs. Metal Detection: A Comparison Table

To examine the different ways the traditional system approach malfunctions on canning lines, an engineer must assess the different ways both systems work on a fundamental level. The following table outlines the operational differences and application limits of metal detection versus X-ray inspection.

Deep Dive: Why Canned Food Requires X-Ray Over Metal Detectors

Canning lines process and move at large, high speeds, and are made out of rigid, non -transparent material. These conditions necessitate a detection system that can ignore the container and work with the contents.

Overcoming the Metal Packaging Blind Spot

Metal detectors work by setting an electromagnetic field. When a metal object moves through that field, it triggers an interruption, and the object is removed from the line. The metal packaging used, which is often tinplate and aluminum, is a conductor. When a metal can is transported to the metal detector, that metal can will create an extremely large interruption (or many interruptions) to the field. This is known as the Faraday cage effect. The detector will have no visibility of anything that is packaged inside the metal can.

Line architects cannot use metal detectors as part of the sealed can inspection process. If a facility uses metal detectors, they must be positioned before the filling and sealing processes. This creates a huge blind spot. If a machine malfunctions during filling or sealing, the can in question is sent down the supply chain as a can containing dangerous materials. This is where X-ray technology is useful. X-rays depend on an entirely different principle than metal detectors, which use magnetic fields. The x-ray software uses the density of the metal can wall as a baseline and subtracts that to inspect the contents of the sealed container.

Detecting Glass, Bones, and High-Density Plastics

Canning facilities often use disjunctive machinery that is susceptible to non-metallic wear parts. Also, some agricultural products can contain debris from the field. Consequently, metal cans are known to conceal broken glass, small stones, or bones coming from the harvested vegetables, and broken guide rails made from high-density plastics (PTFE or Acetal) and plastics in the conveyor system.

Metal detectors will never be able to identify glass, stones, or plastics. However, X-ray systems will. Glass and stones will appear on the X-ray grayscale image as darker spots due to the higher density values they possess. Likewise, high-density plastics and rubber gaskets (often industrial-grade) will be able to be detected due to their density. Production engineers are able to identify and remove both metal and non-metal non-hazardous contaminants before the product is sealed, thanks to the X-ray systems.

Beyond Contaminants: Unlocking Value in Canning Production

Modern production machines need to be able to provide the most value for investment. X-ray systems are able to provide multiple quality control services and are therefore more than simple safety tools. They are complete systems for the control of product safety, even checking for missing product components.

Accurate Fill-Level Inspection

Consumer protection laws impose severe fines for underfilled cans as well as risk prosecution for the entire business. An overfilled can is also a waste of product (giveaway) and can adversely affect the closing head on the double seam by compromising the integrity of the seam.

X-ray systems carry out highly detailed inspections and check for contaminants at the same time. While the X-ray examines the can, the software analyzes the liquid or solid content and maps a horizontal line. Engineers set the zone parameters in the software. If the content line falls below or above the set parameters, the system will indicate a rejection. This way, plant managers can immediately adjust dosing equipment and reduce product giveaway, all while keeping the production line running.

Identifying Dented Cans and Seal Defects

The can’s hermetic seal and geometry are vital for the product’s safety and integrity. Damaged cans can be more than cosmetic—severe dents on the can’s seam can break the internal lining or vacuum seal, creating the risk of botulism and spoiling the product.

The software comes equipped with edge-detection algorithms. When a can moves past the sensors, the software analyzes the geometry of the structure. It examines the double seam profile and the walls for defects. If the system finds a dented wall, a missing lid, or a dented flank, it will eliminate the can. This ensures that no dangerous or unsellable products end up being offered for sale in stores.

Ensuring HACCP Compliance & Data Logging

B2B procurement focuses on compliance. Food safety audits with GFSI, BRC, or IFS certifications require extensive documentation. Auditors look for more than just the hardware. They want to see that the plants are capable of active, system-supported monitoring and recording of quality events.

Industrial X-ray machines are advanced data logging devices. The system software logs the time, date, and product code for every unit that passes through the machine. More critically, the machine captures and logs an image of any unit that is rejected. This image constitutes evidence of the defect or contamination. Logged data is utilized by QA teams to trace the problem to specific upstream equipment, demonstrating full compliance with HACCP during unannounced audits.

Integrating X-Ray Systems into High-Speed Canning Lines

Choosing the right X-ray technology is the first of many steps. Integrating the system into the actual production setup is of high importance. Canning lines can be difficult. They require specific mechanical solutions for their combination of high speed and heavy products in rigid containers.

Strategic Placement on the Line

Line architects have to figure out the best spot to put the X-ray machine on the line. Canned goods can be deployed at two main locations: directly after the seamer, or at the end of the line just prior to the case packer.

If the X-ray is placed after the seamer, it will be able to detect problems first. This means that if the filler or seamer starts shedding metal, the X-ray will detect it, and the plant will be able to stop the line and control the amount of contaminated product. However, these locations tend to have a lot of washdown moisture, and they fluctuate in speed.

If the X-ray is placed right before the case packer, it will be able to make sure the product is in its final state prior to inspection. This will allow the X-ray to inspect the product for any defects that may have occurred during the cooking (retorting) or label application. This location usually has more consistent speeds. However, if this location is the case for a recurring drop in product contamination, it means that a lot of cans will already have to be destroyed at this endpoint. This means that the line architects must make a decision based on analyzing the specific failure risks of upstream equipment.

Managing High Throughput and Rejection Mechanisms

When it comes to modern canning technology, canning speeds can go as fast as 1000 cans per minute, to even 300 cans per minute. At this rate, it is imperative that the product is presented to the X-ray sensor and the precise mechanical synchronization is actually removing the defects.

Cans need to enter the X-ray beam at a specific, customizable pitch. Otherwise, if they touch, the image processing software will determine false rejects. To avoid this, engineers use timing screws and/or transfer screws, where custom spacing is required prior to the inspection zone.

At high speeds, particularly with heavy metal cans, the rejection mechanism can be extremely critical. High-energy cans can cause serious injury. For instance, standard mechanical pushers can indent, dent, rupture, and/or spill the rejected can and cause nearby acceptable cans to be pushed over. As such, engineers will specify high-speed air blast rejecters and servo-driven diverters. Moreover, the compliance standards require a reject confirmation sensor. This lockable reject sensor provides confirmation that the reject target did not just continue down the line beyond the reject system.

Addressing Radiation Concerns in Food Inspection

Plant managers are frequently met with questions regarding the safety of industrial X-ray systems. To ensure the confidence of the buyer and the operator, the systems must permit an understanding of the physics of X-ray inspection.

• Alimentación Seguridad: For industrial food inspection, low-dose ionizing radiation is used. The X-rays pass through the product without affecting the nutritional value, texture, or taste of the food. The food does not and will never be radioactive or have any radioactive contamination.
• Operator Seguridad: Modern systems have an extremely thick stainless steel cabinet, lead-free radiation curtains, and thick curtains at the entrance and exit. The X-ray energy is contained within the structure. The radiation levels outside are below the radiation levels due to human exposure to the natural background. The interlock system shuts down the X-ray generator when the cabinet doors are opened.
• Compliance: X-ray inspection systems are fully compliant with the FDA, WHO, and your local atomic energy authorities.

With all safety and technical concerns resolved, the ultimate success of your quality control relies on seamless line integration. Ready to build an ‘X-ray-ready’ canning process? Contact our engineering experts today to design a high-speed packaging line that perfectly synchronizes with top-tier inspection systems.