Baked snack food product safety and quality can benefit from the use of food x-ray inspection, metal detection, and checkweighing equipment. There are multiple places on the processing and packaging line where installing these systems can positively impact the quality, accuracy and safety of the food item being marketed. Here are some of the most frequently asked questions and answers to help you choose the best food safety inspection systems for your application.
A: Product effect occurs when a product has a conductive property which affects the magnetic field generated by the food metal detector. 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 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.
A: The ideal time to run the loaf of bread through the X-ray equipment is prior to bagging. Bread is typically conveyed through the X-ray machine with its longest dimension leading. At the point of entry, there is a lead shielding curtain, which sometimes causes the loaf to roll on its side as it passes through. This is not problematic for the X-ray machine; however, incorrect orientation can negatively impact the bagging operation that immediately follows. On specialty bread lines, where volumes and production speeds are slower, loaves can be positioned so that the short dimension leads. Entering the machine that way minimizes the curtain’s contact with the bread, thereby preventing loaf roll over.
A: Since bagel and pretzel products are typically sold in multiples, the objective is both contamination detection and ability to verify count. Additionally, pieces can break off during the production process. Food X-ray inspection is the best technology because it can be deployed to spot broken pieces of pretzels or missing components (multipack counts).
A: 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 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 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.
A: Food metal detectors 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 that can accommodate the case size.
A: Although most snack foods don’t have the product effect issues found in baked items, spotting contaminants is challenged by the packaging material of choice. The majority of snack foods marketed today are packaged in metalized film which is formed into a bag via a form-fill-seal (f/f/s) machine or flow wrapper. This means that these packages are not good candidates for metal detectors. Rejection of products in the food metal detector equipment is also challenging because packages tend to be small. With these process and material obstacles in place, food X-ray inspection equipment is the ideal solution to address snack food inspection challenges.
A: 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 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 reduces that number of escapes significantly, because it’s like having five metal detectors back to back running the same package at different frequencies.
A: Checkweighers are a critical component of most packaging lines. Making the weight specified on the label is an important issue with regulatory and brand equity implications. However, it is also critical that expensive ingredients are not being given away in the form of overfills. Additionally, with products that have tight packaging tolerances, such as bars that need to fit in a wrapper with specific dimensions, products that exceed size tolerances can very quickly shut down a production line. Food checkweighers can signal production on the fly to make a fast adjustment to make sure that the specifications are being met.
A: There are several points in the baked goods/snack foods production process that benefit from food safety inspection (metal detectors, X-ray inspection) and checkweighing technology. Here are some examples.
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.
Checkweighers are a critical component to any baking or snack foods operation. Close tolerances need to be kept to avoid giving away costly ingredients—or on the opposite end of the spectrum—under filling, thereby not meeting legal requirements and negatively impacting customer trust.
Read the white paper: Market insights and solutions: packaged baked goods & snack products
Read A Practical Guide to Metal Detection and X-ray Inspection of Food, a newly updated and expanded foreign object detection ebook for the food industry, to: