How to Select X-Ray, Metal Detection Systems
Here’s what you need to know about X-ray inspection systems, as well as metal detectors and checkweighing equipment.
When dairy processors attend tradeshows, they come loaded with questions for makers of X-ray, metal detection and checkweighing equipment. Exhibitors at the International Dairy Show, PackExpo and Process Expo say that plant managers typically ask:
• Can X-ray systems be used to verify contents as well as detect contaminants?
• Can X-ray be applied to pipeline application involved in aseptic processing?
• How easy is it to clean the equipment?
• Can the equipment detect plastic liners and plastic gloves?
• Can I get data from the equipment that will allow me to analyze my production?
• What type of environment can your metal detectors withstand?
• Why use X-ray detection instead of conventional metal detection?
For the answers, Dairy Foodsinterviewed nine vendors of X-ray inspection systems, metal detectors and checkweighing equipment. Here’s what they had to say.
Generally speaking, fluid milk, ice cream, cheese and yogurt call for the use of specific inspection technologies. Notes Christopher Young, a product manager at Anritsu Industrial Solutions USA, “Any fluid or slurries or pumped products can be inspected with a pipeline X-ray system. Performance in a pipeline is typically even a little better due to the product being thin in profile and quite uniform.”
Yogurt lends itself to X-ray systems because processors use metalized films and foils in the packaging, he says.
But, as Steve Gidman of Fortress Technologynotes, “A metal detector can be used in any conceivable configuration (providing the packaging does not contain metal). X-ray technology is limited to either conveyor or pipe-line applications. Metal detectors are by far the industry standard for contaminant detection equipment in the dairy industry. Understanding the advantages and limitations of each technology is essential.”
“For fluid milk, we recommend the use of [our company’s] side view X-ray system that can confirm contents and detect contaminants,” says Allan Anderson of InspX LLC. A pipeline inspection system can be used prior to packaging to inspect flowing milk products for contaminants such as metal, glass, many plastics and stones.
Side view X-ray systems are also used to confirm contents and to detect product voids, or air pockets, in ice cream, Anderson adds.
“With the addition of metal foil seals, X-ray systems are highly recommended for content verification, as well as contaminant inspection,” Anderson says.
Packaged products can be metal detected and X-ray inspected using conveyor-based systems.
“With regards to X-ray technology, it can be used on packaging lines after a foil safety seal has been placed on the container (for example, on yogurt cups) without compromising the detection of metal foreign objects,” says Ray Spurgeon of Eriez.
He says that historically, processors used liquid line metal detectors on filler heads, which left products vulnerable to other process equipment introducing metal prior to the capper or sealing machines.
“Another shortcoming of metal detection equipment is it operates using a balanced electrical field that is subject to substandard detection of stainless steel compared to X-ray’s. This is unavoidable, as the phase angle (meaning how something looks to a metal detector) of stainless steel and conductive products are nearly identical. What this means is that the metal detector actually masks out stainless steel, making it difficult to detect.”
Because of high levels of product effect (such as salt and moisture in cheese products), traditional metal detectors are somewhat limited in performance, says Gary Wilson of Bizerba N.A.X-ray equipment is not affected by these elements and provides a much higher level of foreign body detection, he says. X-ray can also monitor weight issues, size issues, and can even monitor the level of holes (eyes) in Swiss cheese with specific software programs.
Spurgeon makes the point that X-ray technology cannot detect everything. “More often than not, processors believe this technology is a panacea and will detect everything,” he says. They mistakenly believe X-rays can detect plastic, insects, rubber, rodents, wood and paper.
“In the final analysis, an X-ray system will not detect these foreign objects as there is no density difference between them and their product. That said, X-ray technology is superior to metal detection when scanning most conductive products.”
He adds that another “misconception” is that X-ray technology is not affordable. “In fact, the price point of a packaging system is very close in price to a comparable metal detector/checkweigher combination system.”
A role for checkweighers
“Ice cream and cheese are typically good candidates for both metal detection and X-ray inspection, depending on the application, and any packaged product can be a good candidate for checkweigher usage,” Young says.
“Checkweighing should be used to assure packaged dairy products are not under or overfilled,” says Bob Ries of Thermo Fisher Scientific.
Young also makes the point that checkweighers can provide real-world cost savings because they allow tighter portion controls and/or dynamic filling controls automatically sending adjustments to the fillers.
“There are high-quality screening and filtration systems available which can provide removal of any possible contamination,” notes Wilson.
“However on the cream, cheese and yogurt products, there are typically issues with (desired) particulate that prohibits filtration. Metal detectors, X-ray inspection and checkweighers are all commonly used on these sorts of products.”
Updates to equipment
Dairy Foods asked vendors about technology improvements or new features added to their equipment, and how they apply to dairy foods processing or packaging. With metal detectors, the main emphasis has been finding ways to improve detection levels that is acceptable to food safety standards, says Wayne E. Eide of Advanced Detection Systems.
“For example, five years ago, many dairy processors didn’t have metal detectors. Today, due to HACCP and dairy processor quality improvement initiatives, metal detectors are playing a key role towards ensuring the food is safe when it reaches the grocery shelf.”
Creating reports and analyzing the results helps dairy processors.
“Options such as USB data retrieval systems make it simple to retrieve reports from metal detectors and X-ray systems, helping to comply with regulations,” says Robert Rogers of Mettler-Toledo.
He says that systems incorporating “condition monitoring” features help to promote proactive behaviors instead of reactive behaviors.
“The system continuously monitors the condition of critical settings within the system and provides warning if they begin to fall outside of optimums. Another feature is the due diligence feature that helps to verify a contaminated package was properly removed from the production flow and alert when it was not,” he says.
Anderson’s company has a new triple-beam system for high-resolution glass inspection and enhanced systems for both pipeline applications and high-speed side-view systems for rigid packages. The equipment has the ability to detect “glass in glass” as well as contents verification. It is used for dairy-based coffee drinks packaged in glass.
Heat and Controlsells CEIAin the United States. Todd Grube says CEIA “has developed technology that uses multiple frequencies simultaneously to detect metal while compensating for errors caused by product effect conditions.”
The advantage of this process, he says, is that “it maintains the highest-possible level of metal detection sensitivity while preventing false detection signals caused by product effect conditions, such as salt and moisture content in products, and changes in ambient air and product temperature.”
CEIA’s multifrequency metal detector has proven particularly effective with high product effect foods, like cheese, and wet or frozen products. An “auto-learn” system continuously tracks product effect during production and automatically adjusts to maintain optimal detection sensitivity.
Grube says CEIA has taken the lead in providing inspection data security, traceability and integrity by complying with FDA Title 21 CFR110 requirements for food safety. Data from each inspection and rejection are stored in CEIA’s events memory to certify production quality, the inspection activity, programming operations and periodic functional test phases.
Young says that Anritsu released a new X-ray system to better inspect products with significant product variation and still look for smaller or hard to find contaminants such as wire, stones, glass and bone.
“Most dairy products don’t have bone issues. However the DUAL X system was designed as an enhancement to existing X-ray technology and can offer significant improvements in detection levels in certain applications.”
New metal detectors from Eriez have a patent-applied-for capability that can replace traditional phasing to ignore product signals and find smaller metal contaminants in wet, salty dairy products.
“It works by learning and cancelling the conductive and magnetic product signals on a real time basis. The result is 20-50% smaller metal contaminants can be detected in high product effect foods, such as sliced cheese and yogurt cups. It was developed by working closely with a large cheese packaging company,” Spurgeon says.
Thermo Fisher Scientific’s X-ray system not only finds small contaminants but can also utilize the X-ray image to estimate mass. Although this is not as accurate as a checkweigher, this software function can be used for “free” to check for things like fill level and gross weight, says Ries. “It is particularly effective with homogeneous products like chunk/block cheese.”
Compared to two years ago, Fortress Technology’s metal detectors offer “significantly higher performance” in sensitivity and data collection, says Gidman. “Our newer models incorporate ethernet, USB and wireless connectivity for easy data collection and adhere to HACCP compliance. Our latest technology can be installed in a detector built 15 years ago.”
Too many features?
With all the bells, whistles and improvements to equipment, Dairy Foodswanted to know if dairy processors are making the most of all of these new features and functions.
“Most features are utilized as they are usually discussed and purchased at point of sale, however some services are often under utilized such as a service agreement,” says Rogers. He adds that a documented, routine visit from a factory-authorized representative is “a great way” not only to comply with on-going maintenance provisions within food safety law and regulation but it also a way to identify problems before they impact safety or production.
Ries says he finds that because the Intellitrack XR on his company’s equipment is a new approach in metal detection, it is not well understood by long-time metal detector users. So the company wrote a whitepaper to explain the concept, use and benefits.
“We also have included it as a standard option in all our APEX metal detectors so it can be easily used at any time on any product,” he says.
“For difficult to audit pipeline metal detectors we offer an option called Auditcheck. Again this is a very unique capability that could be better understood by metal detector customers. It is particularly valuable in piped liquid applications because it provides a way to pass a piece of metal through the detectors’ fields to verify it is working correctly. Many times this is impossible to do in any other way because a test ball/piece inserted in the product stream could be lost.”
Gidman says that processors should regularly use testing procedures and record keeping.
“It is important to not overlook the advantage of installing metal detectors at specific check points along the manufacturing process and not just at the end of the production line.” He says that to obtain the maximum performance of a metal detector, it is important that the guidelines of a proper installation are adhered to and an area survey is performed prior to installation.
Bizerba provides a high level data management system, called Stats.Brain.
“This extremely powerful tool allows the user to monitor not only the equipment performance, but it provides a full statistical analysis of their production,” Wilson says. The data that is generated from the software program becomes a “valuable tool” to help improve line efficiencies and lower production waste, he says.
Dealing with the FSMA
The Food Safety Modernization Act has been law for nearly a year. In response, some equipment vendors have altered their machinery or software.
Advanced Detection Systems responded by introducing three new technologies with a concerted effort to ensure better sensitivity and improved management communication, such as ethernet and USB accessibility, says Eide.
“It is important to note that most of the Act is specific towards food processors improving their record-keeping procedures and ensuring a level of food safety exists in the facility. Most processors are trying to understand what their new standards mean to their production.”
He says he finds a significant amount of time is needed to walk through a processor’s inspection requirements, educate them on the capabilities and demonstrate the sensitivity through product testing and a written guarantee statement.
“By providing comprehensive training classes to operators, QC and maintenance personnel, we have noticed that the processor begins to integrate these steps into their process immediately and brings real life meaning to the Safety Act intent.”
Andersoncalls the Food Safety Act “part of a continuing process that is accelerating the consideration and adoption of improved and extended inspection systems in the industry. Although changes in GMP and CCP standards move at an unpredictable pace, the move towards X-ray inspection as an augmentation and enhancement to current contaminant inspection programs is accelerating.”
Ries adds that Thermo Fisher Scientific is starting to see the effects of the law from offshore producers who import products to the United States. “They know they must improve their food safety standards and processes to stay competitive and address heightened awareness of food safety related issues,” he says.
Notes Gidman, “Some of the testing requirements are getting very complicated and having developed technology and features that assist in testing, we can help ensure proper functionality and avoid mistakes while reducing costs all without the user requiring an engineering degree.”
One of the biggest changes the FSMA has brought about is a change in the culture of a facility, says Rogers.
“No longer are we simply installing a piece of equipment into a production line, but we are helping to build a complete foreign-body prevention program. This includes ensuring the correct equipment is properly installed and the users of the system are fully trained in the operation and utilization in order to identify hazards and implement corrective actions to prevent the contamination from happening in the first place,” he says.
Focus on automation, service
Equipment vendors are adapting to changes in the dairy industry, including consolidations, processing innovations and packaging requirements.
Says Eide: “The advent of smarter, easier-to-use and greater sensitivity technology has replaced older technology. Also removing as much of the ambient conditions that adversely affect the detector has also gained wide support and is evident in the conveyor designs and the birth of patented technology such as the patented ProScan Max that cancels the negative sensitivity effect caused by vibration noise.”
“All inspection systems benefit from the basics of industry attention to automation,” says Anderson. “Automation implicitly means faster speeds, longer hours and fewer people. Each strongly encourages use of inspection systems as necessary adjuncts to any automation program.”
Pointing to the use of metallized films and foil elements to extend shelf life and control product quality, Anderson adds that many packaging changes encourage (or even dictate) the use of X-ray.
Says Gidman, “The primary changes over the last few years have been a focus on service response time and cost. As more and more customers are using metal detectors as critical control points (HACCP), the response time (and cost) for service is a key factor in determining suppliers. With local service covering key areas of the dairy industry, Fortress has a great advantage in response time and service cost.”
Changes in regulations, new packaging technologies and updates to equipment are just some of the reasons plant managers need to stay current with the equipment used in processing. Use the Dairy Foodsbuyers’ guide (available at www.dairyfoods.com) to find equipment vendors. Trade shows give managers the chance to see the machinery first hand and to learn the technical specifications.
Meet the Panel
Allan Anderson, InspX LLC, Fremont, Calif.
Wayne E. Eide, Advanced Detection Systems, Milwaukee
Steve Gidman, Fortress Technology, Toronto
Todd Grube, Heat and Control, Hayward, Calif.
Bob Ries, Thermo Fisher Scientific, Minneapolis
Robert Rogers, Mettler-Toledo, Tampa, Fla.
Ray Spurgeon Jr., Eriez, Erie, Pa.
Gary S. Wilson, Bizerba N.A., Sandston, Va.
Christopher Young, Anritsu Industrial Solutions USA, Elk Grove Village, Ill.
Tips for Plant Managers
•Maintain records of sensitivity tests, and the results for each product during technical, operational and sanitary audits.
•Express sensitivity standards as the minimum detectable ball size and indicated by the nominal spherical diameter and material (e.g. 2.3 millimeter diameter type 316 stainless steel).
•Properly document the sensitivity standard and effectively communicate it throughout the organization. Make it readily available to appropriately trained verification personnel.
•At least three tests per material type and aperture position are generally considered realistic for most testing purposes. When good detection capability has been established during implementation, fewer tests may be required as acceptable practice.
•Access to sensitivity adjustment controls should be limited to properly trained employees. Prevent access by others through password protection or lockout of the appropriate controls.
•Use factory-trained personnel to properly train your employees. Train, train and retrain to assure all your procedures are being followed at all times.
•It is essential that workable procedures and processes be implemented for each application. Start-up assistance and training for new equipment purchases is critical to implementing proper operation and procedures.
•Have a person in the plant who can answer many of the questions that may arise after the initial installation.
•Customizable service agreements can provide another level of assurance that the equipment is functioning correctly and meeting the customer’s requirements.
•Look at “end of line inspection” or closed-package inspection since it provides assurance the product can no longer gain contamination prior to reaching a customer.
Source: Respondents to Dairy Foods’ questionnaire
What Processors Need To Know
Dairy Foods asked: What key points are important for a dairy processor to know about X-ray, metal detection and checkweighing equipment in general, and your products in particular?
•Wayne E. Eide: Removing external factors is crucial from any perspective. Detecting very small pieces of metal requires the correct sized detector and internal electronics that have the capability of completely removing the product effect and enhancing the detection levels, especially in cheese applications. Having two channels of detection, one for product and one for metals greatly improves the sensitivity.
•Allan Anderson: Speaking for X-ray systems in particular, I would emphasize that all X-ray systems are not the same. X-ray systems should be appraised in terms of what they should be able to do: detect glass in glass, bone in meat, metal in metal cans, and such things as stones in beans.
•Bob Ries: Many processors underestimate the value of proper maintenance of these systems from trained technicians. This can result in expensive downtime, failed customer audits and scrap/recalls.
•Steve Gidman: It is important to understand that X-ray systems, metal detectors and checkweighers are for the most part complimentary technologies. The proper use of each type of system and understanding the capabilities and limitations of the technology is essential for proper implementation of each type of system. Key points dairy processors should understand before implementing a specific technology are the cost versus benefits ratio.
•Gary S. Wilson: Of special interest is the machine’s ability to deal with the typical harsh wash down and sanitation environment.
Advanced Detection Systems........ www.adsdetection.com
Anritsu Industrial Solutions USA....www.detectionperfection.com
Bizerba N.A........................................ www.bizerba-na.com
Fortress Technology............. www.fortresstechnology.com
CEIA (available from Heat and Control).......... www.ceia.net
InspX LLC.................................................... www.inspx.com
Thermo Fisher Scientific............ www.thermoscientific.com/productinspection