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View additional product information for Sentinel Multiscan and Selectscan Metal Detectors - FAQs (SENTINEL1000, SENTINEL3000, SENTINEL5000)
27 product FAQs found
Metal detection works very well with dry/kibble pet food and treats that do not have a product effect that wet or moist pet foods do. Metal detection equipment provides reliable, cost-effective protection from even the smallest metal contaminants found in pet food production anywhere in a process. If the packaging material contains metal, X-ray inspection would be the right choice. In addition, if there are other contaminant concerns such as stone, high density plastic or glass, X-ray inspection systems will detect these contaminants as well.
There are several points in the baked goods/snack foods production process that benefit from food safety inspection using metal detectors (https://www.thermofisher.com/us/en/home/industrial/food-beverage/food-weighing-inspection/metal-detectors.html), X-ray inspection (https://www.thermofisher.com/us/en/home/industrial/food-beverage/food-weighing-inspection/x-ray-detection-inspection-systems.html), or checkweighing (https://www.thermofisher.com/us/en/home/industrial/food-beverage/food-weighing-inspection/checkweighers.html)technology. They are listed below:
1. Incoming ingredients. Most of the larger bakers demand that their vendors meet specific HACCP objectives. They may require that metal detectors be used, provide proof of inspection, etc. Even with those methodologies in place, some will also inspect incoming ingredients. Typical incoming inspection consists of drop through and bulk flow metal detectors.
2. Dough stage. Before the product is baked or otherwise processed, this is an ideal location to conduct upstream inspection. Metal detectors are the equipment of choice because metal-based packaging is not part of the process at this stage. Bar products are another example. They can be examined right after sheeting, or after the individual bars are cut, or before the product goes into the wrapper. Alternatively, they can also be inspected after packaging.
3. After baking/before packaging. The inspection equipment type will depend on the product type and whether or not its formulation creates a “product effect”. Warm, moist, high salt content products such as breads are more suited toward X-ray equipment, while metal detectors perform well with typically-inert snack foods. Checkweighers can also be located at this stage to make sure that the product weight falls within the min/max specifications and will not create problems (such as line stoppages due to oversize) at the packaging stage. Checkweighers can also be used to confirm that all of the late-stage filling components, such as icing and other toppings, have been properly dispensed.
4. After packaging. The recommended inspection equipment type is dependent on the packaging material or combination of materials that have been selected for this product. Metal components such as aluminum foil trays or metalized firm structures are much more suited to X-ray inspection. Flexible materials without a metal component, paperboard folding cartons and/or a combination of the two, work very well with metal detectors. Checkweighers are frequently located at this stage of the operation.
5. After case packing. Some bakers or processors prefer to inspect after the final packaging stage: case packing. This is typically done via X-ray inspection, provided that the unit is large enough to accompany a case. In addition to inspection, the X-ray system's ability to detect missing pieces will help ensure that the specified count has been loaded into the case. In certain situations, especially when X-ray inspection is not included at the end of the line, checkweighers are placed here to ensure that the proper number of packages are contained inside the case.
Every detection system has a probability of an escape.The type of metal, its shape, position, product effect, etc., all are factors in detecting a metal contaminant. Multiscan technology (https://www.thermofisher.com/order/catalog/product/SENTINEL5000?SID=srch-srp-SENTINEL5000) provides unmatched sensitivity and the highest probability of finding ferrous, non-ferrous, and stainless steel metal contaminants in challenging applications such as dairy, meat, poultry, bread, and other applications with high product effect. Multiscan technology reduces the number of escapes significantly, because it's like having five metal detectors back to back running the same package at different frequencies.
Food metal detectors (https://www.thermofisher.com/us/en/home/industrial/food-beverage/food-weighing-inspection/metal-detectors.html) work extremely well with frozen baked goods which no longer have a product effect that “just out of the oven” versions do. The challenge is to make sure that the freezer is efficient and is holding the product at the correct temperature. If a product isn't completely frozen, its unfrozen center will have a tendency to look like a piece of metal to the detector.
In addition, many cake and pie products are frozen immediately after production, so some bakers choose to inspect after the items are case packed using food X-ray inspection (https://www.thermofisher.com/us/en/home/industrial/food-beverage/food-weighing-inspection/x-ray-detection-inspection-systems.html) equipment that can accommodate the case size.
The recommended food safety inspection machinery type for cakes and pies is dependent on the packaging materials used. Since most pies are in aluminum foil pans, food metal detectors (https://www.thermofisher.com/us/en/home/industrial/food-beverage/food-weighing-inspection/metal-detectors.html) can be useful to examine ingredients and dough. However, after the pie has been placed into the pan and/or folding carton, X-ray inspection (https://www.thermofisher.com/us/en/home/industrial/food-beverage/food-weighing-inspection/x-ray-detection-inspection-systems.html) should be used. Cakes also sometimes rely on aluminum foil pans, folding cartons, and metalized film, so the inspection solution recommended is also X-ray.
“Product effect” occurs when a product has a conductive property which affects the magnetic field generated by the food metal detector (https://www.thermofisher.com/us/en/home/industrial/food-beverage/food-weighing-inspection/metal-detectors.html). This is typically found in high salt, high moisture product environments. For example, warm bread coming out of the oven, coupled with its salt content, tends to have a high product effect. This negatively impacts the metal detector's ability to distinguish between actual non-ferrous metal contaminants and the false signal given by the combination of typical product attributes. This is further complicated by the varying densities, air bubbles, and other physical characteristics of each loaf, since no two loaves are exactly the same (there also are variations between bread types). In these situations, food X-ray inspection equipment will produce significantly better results since product effect is not a factor.
These are the four best places in the dairy production process that benefit from inspection using metal detectors, X-ray equipment, or checkweighing technology:
- Incoming ingredients. Drop-through and bulk-flow metal detectors are ideal choices for dairies wanting to inspect incoming ingredients such as powders, fruits, or nuts before incorporating them into the finished product.
- Liquid flow. Metal detectors work in pipeline applications for novelties and other liquid-fill products.
- After filling/packaging. The dairy product inspection equipment type will depend on the product type and its potential for product effect. Since many dairy products have high moisture content, they are more suited for X-ray inspection at this stage. Checkweighers can be located here to make sure that the product weight is within minimum/maximum specifications with an option for electronic real-time feedback to the filler to adjust production on the fly.
- After case packing. Some dairies can benefit from inspection after final packaging: in-case packing. This is typically done via X-ray inspection if the case is less than 8 inches high and the machine's aperture is large enough to accommodate a case. The X-ray system can be used to confirm that the specified count is loaded into the case. In certain situations, checkweighers can perform this latter function.
Small metal foreign objects have very small signals, and the food metal detector is operating in a factory that has many possible noise sources that can confuse the metal detector electronics and software. Make sure you address some of these sources that can interfere with your testing:
- Large motors turning on and off
- Electronics boxes broadcasting wide spectrums of radiated noise
- Production equipment vibrating and causing the antenna in the metal detector to move ever so slightly
- Electrical power surging and dropping
- Temperatures going from freezing to boiling and back again
Every detection system has a probability of an escape. The type of metal, its shape, position, product effect, etc., all are factors in detecting a metal contaminant. Assume that in the past, you have found that 1 out of 1 million packs (1 ppm) incurs an escape. At the rate of a pack/second, 16 hours a day, 5 days a week, that is an escape about every 3-4 weeks. That escape could cost thousands to millions of dollars. Multiscan technology reduces that number significantly, because it's like having five metal detectors back to back running the same package at different frequencies.
It is widely understood that ferrous metals are the easiest to detect due to their magnetic properties. An electromagnetic field reacts most to ferrous metal, and the lower the frequency, the greater the reaction. Conversely, stainless steel, which contains only a small amount of ferrous metal, has little or no magnetic property. Metal detectors must run at a high frequency to find stainless steel because the high frequency field induces a current in the stainless steel which creates a new field that interacts with the original field in the metal detector to create a signal.
Using up to five frequencies does not mean that Multiscan technology will create five times the number of false rejects. If you discover that any of rejects were false, you can quickly jump to the controls that need adjustment.
The best frequency is the one that catches the metal, but unfortunately, different sizes of the same metal have different magnetic and conductive reactions. And the shape, orientation, and position of the metal can change the resulting signals in a metal detector. The best metal detector technology is the one with the ability to scan multiple frequencies at once. The more frequencies it can scan, the better.
“Product effect” occurs when a product has a conductive property which affects the magnetic field generated by the metal detector. This is typically found in high-salt, high-moisture products. And it can be a challenge to food safety. The best way to overcome this challenge is to utilize additional frequencies. Food metal detectors (https://www.thermofisher.com/us/en/home/industrial/food-beverage/food-weighing-inspection/metal-detectors.html) that are equipped with Multiscan technology (https://assets.thermofisher.com/TFS-Assets/CAD/Product-Information/Sentinel%20White%20Paper.pdf) enable operators to pick a set of up to five frequencies from 50 kHz to 1000 kHz. The technology then scans through each frequency at a very rapid rate. Running five frequencies helps to get the machine close to ideal for any type of metal you might encounter. Sensitivity is optimized, as you also have the optimal frequency running for each type of metal of concern. The result is that the probability of detection goes up exponentially and escapes disappear.
The Multiscan food metal detector automatically balances frequencies electrically. While it takes a few minutes the first time, it has a big impact on performance. To save time, the last balance data is used unless a new frequency is added. The software also runs an autobalance process continuously to remove the final errors caused by very small imbalances. There is even a balance diagnostic screen for advanced users to make sure balance is correct and there isn't an internal problem with the metal detector.
You get immediate feedback. When running, Multiscan technology allows you to view all the selected frequencies in real time and pull up a report of the last 20 rejects to see what caused them.
While metal detection can be challenging even with five frequencies, Multiscan technology can be easy to use. Multiscan metal detectors utilize wizards, graphical displays, and reports to help with set-up, use, and adjusting performance.
Multiscan food metal detectors (https://www.thermofisher.com/order/catalog/product/SENTINEL5000) utilize a true spectrum of frequencies along with new signal processing, thus reducing the probability of an escape to near zero. The critical control point (CCP) scans up to five completely adjustable frequencies to find metal types and sizes previously undetectable. It's like having up to five metal detectors back to back in a production line. It reduces the probability of an escape by many orders of magnitude.
Small metal foreign objects have very small signals, and the food metal detector is operating in a factory that has many possible noise sources that can confuse the metal detector electronics and software. Make sure you address some of these sources that can interfere with your testing:
- Large motors turning on and off
- Electronics boxes broadcasting wide spectrums of radiated noise
- Production equipment vibrating and causing the antenna in the metal detector to move ever so slightly
- Electrical power surging and dropping
- Temperatures going from freezing to boiling and back again
It is widely understood that ferrous metals are the easiest to detect due to their magnetic properties. An electromagnetic field reacts most to ferrous metal, and the lower the frequency, the greater the reaction. Conversely, stainless steel, which contains only a small amount of ferrous metal, has little or no magnetic property. Metal detectors must run at a high frequency to find stainless steel because the high frequency field induces a current in the stainless steel which creates a new field that interacts with the original field in the metal detector to create a signal.
When metal is missed on the leading or trailing edges of a standard food grade metal detector, adjust sensitivity per the manufacturer's recommendation and when required, increase metal size until it is detected.
Place metal spheres in multiple locations on the food package, always trying to keep the metal at the midline of the head height and middle of the package. Test the leading and trailing ends, both sides, the absolute center of package (whenever possible), and the top. Specify the smallest metal detected in ALL locations.
For all food grade metal detectors, eliminate as much background noise as possible. Then start with the manufacturer's default settings. Ensure that production samples are used for setup.
The default sensitivity setting is 6 dB (or 50%) below the peak signals encountered during the learn process. If the product has an inconsistent signal, this generally is a safe setting. If the signal is very consistent, you may be able to increase sensitivity to 3 dB (or 30%) below the peak signals. For standard metal detectors, set the detect thresholds to about 1.2 to 1.5X the maximum product signal. For Multiscan food metal detectors, the equipment testing best practice is to set both in and out of phase at 3 dB less (1.4X) than the reject signal (36 dB).
“Frozen” is a general term. For metal detection, it is critical that the actual product temperature and state are fully understood as results will change drastically. Products that are completely frozen to the core will often “learn” as a dry product does with little to no product effect. In contrast, a partially frozen product will respond much differently passing through a metal detector and can cause excessive false rejects as production conditions vary throughout the day. Ideally, it is best to set up the metal detector for frozen food industry in the production environment at the correct temperature and state.
For wet and conductive food products, center the package vertically in the head, ensuring the same amount of distance is above and below the package. Often this means that the head height will be larger than the standard sizing recommendation. This helps reduce the product signal by moving the product away from the electromagnetic coils.
For most applications, size of the aperture is 2 inches wider and 2 inches taller than the largest package intended to pass through the food grade metal detector.
The size of the food metal detector head is based on the dimensions of the food package. Always simulate production conditions as closely as possible, including speed, temperature, and orientation of the product.