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Key Tips on Improving Contaminant Detection in the Dairy Industry

Key Tips on Improving Contaminant Detection in the Dairy IndustryS+S Inspection Inc.

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Fluid milk is pasteurized and packaged without a lot of processing. The greatest risk is likely contami-nants from filling equipment landing in the packaging. Typically, rare-earth magnets are used on the pipe-lines as a primary check for contaminants. While this strategy does not address inspection after packaging, regular maintenance checks of the filling machinery can reduce the risk of parts falling into containers. However, the need for end-of-line inspection has in-creased for retail fluid milk products due to quality programs such as HACCP, BRC, IFS and as a result of the new Food Safety Management Act (FSMA). Employing metal detection at this stage is becoming common, since these technologies will detect the lar-ger pieces that can end up in the container. But, when aluminum foil seals or me-talized materials are incor-porated into the packaging, x-ray systems/technologies need to be incorporated to achieve acceptable perfor-mance for end-of-line in-spection.

Butter is packaged for retail and for industrial use. It is pumped to packaging machinery; therefore, ty-pically rare-earth liquid magnets and pipeline metal detectors are employed. These devices are excel-lent for eliminating metals from the product. In fact, their performance is better than would be achieved from most end-of-line inspection systems, and they are much less expensive than x-ray systems. The highest risk of metal conta-mination in butter occurs in the processing area. The-refore, inspection within the pipe addresses this risk the best, when considering per-formance versus cost.

To inspect butter packaged for retail in aluminum foil, X-ray is required. Nevertheless, since most of the risk of detecting metal contaminants is addres-sed with inline magnets and pipeline metal detectors, x-ray is not a common solution for foil-wrapped butter. To comply with some food safety protocols, then you must have some kind of end-of-line inspection sys-tem. If the packaging is paper, then metal detection is usually acceptable, if the packaging contains foil, then x-ray is the solution. The type of packaging ma-terials used; governs tvhe technology chosen for the solution. Metal detection – without foils, x-ray - with foils.

Butter for industrial use is shipped in 50 pound cubes or larger vessels. Metal detection on the 50 pound cubes is relatively common, however metal detectors large enough for this application typically only detect larger contaminants such as “nuts and bolts”. The inline pipeline solution described above is the best for industrial butter.

The Dairy Industry presents its own set of chal-lenges regarding reducing the risk of foreign materi-als in fluid milk, butter, cheese, yogurt, ice cream and powders. While each process starts with the same primary ingredient — milk — the end product, pro-cesses and packaging vary, making each of these products similar, but different, in terms of the best so-lutions for contaminant detection.

The further the milk is pro-cessed, the higher the risk is of contaminants entering the production stream, either from machinery or additional ingredients. Milk products are shipped from the dairy to retail sales outlets and to industrial facilities further processing. The detection sensitivities on retail milk products need to be much higher than products destined for industrial use. Milk products destined for industrial use will ultimately have retail-level inspection when these materials are combined to make retail products.

Ice cream production takes milk products and adds many other ingredients such as sugar, fruits, choco-late and other inclusions. Each of these ingredients adds an increased risk for foreign materials, in ad-dition to risks of metal fragments coming from the further-processing machinery. Fresh ice cream is ty-pically packaged at about 24-26°F, when it is soft. At this temperature, ice cream has a significant product affect or can be said to be highly conductive to a me-tal detector.

Key Tips on Improving Contaminant Detection in the Dairy IndustryS+S Inspection Inc.

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There are some metals used in the construction of the ice cream freezer barrels such as ni-chrome and 316 stainless steel that are very difficult to detect. These factors make inspection of retail-size fresh ice cream with metal detection difficult, because the performan-ce for non-ferrous and stainless metals is reduced due to the product conductivity. After the ice cream has been through the hardening process, the ice cre-am is hard frozen, hence the product is significantly less conductive, so better performance is possible. The challenge at this part of the process is that often retail products are bundled, so inspecting the bund-led product through a metal detector requires a larger aperture, so the performance gain may be lost in the larger aperture with a frozen product as compared to a smaller aperture on a conductive product.

X-ray is a practical solution for retail ice cream becau-se, unlike a metal detector, its performance is not af-fected by the conductivity of the product. Stainless steel, the highest risk material, is easily detected with an x-ray but very difficult in a metal detector. Howe-ver, the performance of x-ray may be diminished if dense inclusions such as candies or chocolate chips are part of the ice cream (due to their density). Ano-ther criteria when considering x-ray, is that detection of aluminum is not typically as good as that of a con-ventional metal detector. X-ray will find other contami-nants such as, glass or natural rubber gasket material and is by far the best solution for fresh ice cream. Pipeline metal detection and rare-earth magnets used together address the highest risk of metal con-taminants that occur during processing of ice cream and are the best solution given the cost/performance equation. They should be used in conjunction with end-of-the-line metal detection or x-ray to achieve the best overall protection.

Cheese inspection presents its own list of challen-ges. Cheese shipped for industrial use sometimes does not have any end-of-line inspection, simply because the size of the block may be too large. Th-erefore, most cheese inspection is done on retail products. Rare-earth magnets and sometimes in-pro-cess metal detectors are used on the cheese curd. However, depending on the process, it is sometimes not practical to install these systems, which means each site requires its own review.

Almost always, an x-ray system for inspecting chee-se will provide better metal performance than a metal detector with the exception of detecting aluminum. The metal detector will provide better aluminum per-formance. The decision process on which technolo-gy to employ often depends upon the requirements of the end retail customer or the company corporate standard. Cheese is often cut with wire. These wires can be difficult to detect with both technologies de-pending on the orientation of a wire fragment in the product. Sizing the aperture and operating frequency cor-rectly makes the difference between an effective and inef-fective cheese metal detecti-on system. Thus, when choo-sing between x-ray and metal detection on a cheese retail line, you must always factor in cost, performance, and risk.

Yogurt has the same criteria for pipeline metal de-tection and rare-earth magnets as ice cream or but-ter, since the product is pumped to the filling stations. The best performance is obtained with these tech-nologies, but to accomplish finish-pack inspection, they are often used with end-of-the-line systems, as well. Many yogurt cups are sealed with me-talized film or aluminum foil. The metalized film sealed cups can be inspected in a conventional metal detector with reduced per-formance. If the seal is aluminum foil, then x-ray must be used. X-ray tends to be the better solution for yo-gurt cup inspection.

Key Tips on Improving Contaminant Detection in the Dairy IndustryS+S Inspection Inc.

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Milk and Cheese Powders are also by-pro-ducts of fluid milk. Generally intended for industrial processing, these products are ingredients for pro-cessed foods. Packaged in super-sacks or in 10 to 50 pound bags, in-process rare-earth magnets and metal detectors tend to be the technology of choice in these applications. Metal detection is typically car-ried out on bags up to 50 pounds with performance that is acceptable for industrial products. Often grid magnets and freefall metal detectors are used to ob-tain finer detection levels as the powder exits a sifter. When the product is pneumatically conveyed there are metal detection technologies that also can be used in these lines that reject the contaminants wi-thout interrupting the product flow.

Product Purity is best obtained with strong pre-ventative maintenance on process machinery and several steps of contaminant detection in the process and after packaging. Often, more than one technolo-gy is used, since each type of the most common sys-tems — magnetic separation, metal detection, x-ray — each have their unique weaknesses and strengths. An understanding of the process and the location of the risk points helps ensure that these systems are specified optimally and placed in the best location.

Assigning a person to be the product champion for inspection equipment and equipping them with thorough training allows him/her to integrate the in-spection knowledge into the everyday SOPs used by production. Line operator positions typically have high turnover rates therefore, continuous training is important to the success of an inspection system. Develop a cul-ture where inspection to a given standard includes challenges and documentation that is as integral as any other step in the manu-facturing process. Empower the product champion with the ability stop the process if inspection is incomplete, only this will ensure the system’s integrity and increa-se the overall product quality and food safety.

About S+S

S+S is one of the world‘s leading manufacturers and developers of inspection, separation and sorting systems.

S+S systems are used in process, packaging and production lines throughout industry and in the spe-cialized preparation of materials for recycling. Our goal is to support our customers in achieving their goals. We have developed a range of products un-equalled in versatility and quality. Our machines are employed in various industries for quality assurance, to increase productivity, to protect the consumers, to comply with industry standards and regulations and to protect machinery and plant equipment. We put the customer first; each project is given individual attention to ensure the best solution possible.

S+S Inspection Inc. is the wholly owned subsidiary of S+S Separation and Sorting Technology GmbH based in Schoenberg, Bavaria. We are responsible for all of the S+S business in the US and provide sa-les, service and support capability for the complete range of S+S metal detectors, X-ray product inspec-tion, separation and sorting systems.

Contact: Doug PedersenSales Manager Fooddoug.pedersen@sesotec.usTel. +1 224-208-1900

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