Foreign Object Detection

Because of the environments in which food originates and travels through the supply chain, and the handling and equipment along the way, there will always be potential for foreign objects to be introduced at some point. But following the 5 W’s of foreign object detection and control can help prevent and protect against the risks and dangers of such contamination.

WHO is responsible? It is the responsibility of every person through every step of the food chain to guard against contamination by foreign objects. But, in the final reckoning, it comes down to the food processor or manufacturer to ensure that incoming supplies and outgoing products are foreign-object free. At the bare minimum, said Jeff Kaveney, manager of product marketing and administration for Eriez, many customers require that processors have a metal detector on the line.

Within the plant, some level of responsibility falls across the board to every online operator, said Robert Rogers, senior advisor for food safety and registration for Mettler-Toledo. For example, maintenance has the task of ensuring the equipment is easy to use and repair, while production managers and supervisors are responsible for setting up the system so as to not have false positives and to reduce product waste. “Everyone within the facility has some input and impact,” Rogers said.

WHAT is of greatest risk? “Anything that is removed from its purest state would eventually need some inspection,” said Wayne Eide, marketing manager for Advanced Detection Systems A tomato that is picked off the vine and placed directly on the table would have little chance of foreign object contamination. However, as soon as that same tomato is sliced, the potential exists. And the further processed the object is, the more it is handled—diced, sauced, pureed, etc.—the greater the potential for the introduction of a foreign object. “The further you remove product from its original state, the more it would require inspection,” Eide said.

Thus, the question to ask, according to Eide, is: “Is there a point at which metal [or another foreign object] could have been introduced?” And the answer will be different in every plant and with every product.

Every part of the process and plant can have a potential impact. For example, in addition to potential contaminants introduced with supplies or from equipment or handling, the construction of the facility itself can cause risk. “Every processing plant is constructed a bit differently,” Kaveney said. “It really depends on how the plant is constructed and what type of materials were used when the facility was built.”

As such, Rogers said, it is essential for processors to conduct a robust hazard analysis and implement corrective action. In this way, he said, plants should not simply install equipment to detect contaminants, but should put preventive measures in place to prevent them. “Equipment should not necessarily be considered a contaminant-elimination device but more of a notification device,” he said. If a contaminant is detected, the next step should be to investigate the source and put in preventive measures.

“Hopefully, you get to the point where the device never registers a contaminant,” he said. “Ideally, that’s the goal: for the device to never go off.”

WHERE should equipment be placed? For many processors, detection at packaging—the last step prior to being shipped for consumption—is considered to be a critical control point. While this is important for consumer food safety, adding equipment prior to this point can provide benefits for the processor as well.

“You need something at the very front of the line,” Kaveney said. Many companies put equipment at the end of the line, but if you want to find out where contaminants are coming from, it is important to also inspect incoming supplies, and if there is potential for any line or equipment failure, a detector should be placed at a mid-point as well.

Recent years have seen an increase in general food safety, defense, and product purity, but “even with all that, there is still a big push to have inspection done at several points in the process,” Eide said. This not only increases the ability to detect contaminants but can keep the contaminant from subjecting the process to greater damage and costs and additional risk liabilities.

For example, a piece of metal that started out the size of a nut or washer could get ground or chopped into smaller and smaller fragments causing more extensive contamination as well as potential equipment damage. “If something is breaking down at the beginning of the process, you can catch it so it is caught before it gets further in the process,” Eide said.

Rogers agreed that end-of-line placement is preferred to ensure there is no further threat to the consumer, and beginning is important, depending on the robustness of one’s supplier program. However, “equipment is just a small part of it. It’s having a real robust program designed around it,” he said. “It’s really evaluating the entire process and determining where potential hazards exist and what damage could be caused to the product or equipment.”

WHEN should equipment be checked? Detection equipment, said Eide, “needs to be working every millisecond of the day.” However, the frequency at which inspection equipment is and should be validated varies as much as do the products that are run on the line.

Some plants validate equipment every half hour, some every hour, and some only test equipment at the beginning and end of shifts. But the most common frequency, Eide said, is once every hour. Testing at that level helps to ensure that if a process is breaking down, it will be caught quickly and can be corrected before causing further damage or contamination.

Ideally, Rogers said, a plant should test as frequently as it can maintain the inventory, keeping all product processed since the last test in the facility so a recall does not have to be conducted if something is detected. However, he said, frequency is not as important as proper testing. Many people improperly test detectors by placing the sample on the belt by itself. Rather than “testing for the sake of testing,” he said, “place the sample with product so it goes through the weakest point, and make sure the package is removed from the line.”

In addition to this regular testing, many plants opt for annual or semi-annual third-party or manufacturer equipment audits, Eide said. This provides documentation as well as validation that the process and equipment are working properly. It can also be a quality check to ensure or return the equipment’s capabilities to its original standards.

A validation test should also include checks of the equipment itself, such as ensuring installation of and settings on the equipment have not been changed, and that nothing is leaning against it that could impact its workings, Kaveney said.

WHY is it important? Because there is a high likelihood that a contaminant can be introduced into the food chain, the industry is responsible for removing it. And this removal requires the assistance of equipment, Eide said. Some contaminants are so small they are virtually impossible to see with the naked eye or even be able to be felt if one were to sift through product by hand. Additionally, even if a contaminant were large enough to see or feel, most line speeds are so fast, a person could not keep up with it. Thus, detection equipment is critical for safety of any processed food product, and can be considered, Eide said, “as a low-cost insurance policy when it gets to that level.”

Besides protecting consumers against consumption of non-food objects, foreign-object inspection can protect the processor’s brand reputation, provide peace of mind that contaminated product is not being shipped from the plant, and protect equipment from damage. “It’s not only product purity, it’s protecting downstream equipment,” Kaveney said.

In fact, even having a recall because of foreign-object detection is not necessarily a bad thing, Rogers said. Rather, “it means the system is working, and we are identifying them and getting them out of the system,” he said, adding, “Utilizing devices more as information sources than elimination devices helps the facility highlight where it has problems and use that information to prevent those problems from happening again.”

The author is Editor of QA magazine. She can be reached at llupo@gie.net.