From Detection to Deterrence

Foreign object detection is a long-standing practice for food safety, but, like all food safety practices, its focus is shifting from reaction to prevention: from detection to deterrence.

“It’s a changing world as far as physical contamination,” said Robert Rogers, senior advisor, food safety and regulation for Safeline. In the past, food processors had X-ray or metal detectors because they were told to, but with the trend toward prevention, it’s no longer simply about detection, it’s about using the equipment to set best practices for deterrence.

In the case of foreign material in packaged food, there are four general sources; that is, what Allan Anderson, president of InspX, calls “the four Ps: product, package, process, people.”

And when the detection equipment on a line kicks in—rejecting an item or setting off an alarm signal, it means that something in the product that passed through that equipment is materially different than normal.

Although detection and rejection of a physical contamination is made by the equipment, the deterrence is established through the setting of a four-step program focused on:

1. Who is responsible for taking action?
2. What is the contaminant that was detected in the rejected product(s)?
3. How is the root cause of the contaminant found?
4. What is done to fix the issue and prevent its occurrence?

1. Who is responsible for taking action?
Most companies have systems that reject contaminated product into a locked receptacle to ensure that no one is able to simply place product back on the line or throw it away without full review. Thus, it is important that it be determined who has the authority to open the receptacle, said Doug Pederson, sales manager of S+S Inspection. “The first thing I tell people to do is to designate who is responsible when that detector activates,” he said. “When it rejects, it rejects for a reason.”

When this is the case, said David Smith, sales manager for Advanced Detection Systems, “Typically, the person responsible for QC would have a key, and policy would say that when a detection is made, that person is notified.”

Detection policy should also dictate when or who determines if a line is to be shut down, with the number of items rejected often being a determining factor. “Some will stop production until it is determined where the [contaminant] came from, others will quarantine the product to determine why it was rejected,” Smith said.

2. What is the contaminant that was detected in the rejected product(s)?
The determination of the contamination may begin on the floor or the contaminated product may be taken immediately to the lab for inspection. On the floor, a QC person may review the images of an X-ray machine or rerun product through a metal detector.

“One thing customers really like about X-ray is that you get an image,” said Bob Ries, lead product manager, metal detection and X-ray inspection for Thermo Scientific. The viewer can zoom in on the item and sometimes identify the object right in the picture, then move on to determining the root cause. For metal detectors, floor action may be that of “divide and conquer”; that is, breaking down the item and passing smaller and smaller pieces of it through the detector until the contaminant can be visually detected.

In the old days, Ries said, people would take product out of the rejection bin, pass it through a couple more times, than assume a false rejection if the system doesn’t go off. “But with tighter HACCP policies and FSMA, they are going away from that,” he said. Additionally, he added, “Most good customers will scrap any rejects; they will assume that everything is real.”

Although a production line is generally not shut down unless there are extenuating circumstances, such as multiple items rejected in a row (which may also set off an alarm or automatic stop), a lot may be quarantined until the contaminant is determined and decision made on what should be done with the product—again, a decision often made by the QA/QC manager.

“When there is a catastrophic failure on something, you will see just that; you will see multiple hits, said Ray Spurgeon, account manager, inspection systems for Eriez. “That’s a red flag.” Contaminants can get into product by coming in with raw materials or by being introduced in the production stream. And if a hard contaminant, such as stone or metal, is carried in with raw material, it can impact equipment and/or product all the way down the line.

Sometimes product rejection will be a quality rather than a safety issue. When the equipment is calibrated, the composition and density of the product is taken into consideration. If the product changes, the equipment can automatically reject it. For example, Pederson said, an extra clump of raisins in bread, extra pepperoni on a pizza, or a soft spot in frozen food could all cause the equipment to detect a difference and reject the product. The decision then needs to be made as to whether this is enough of a quality issue to deem the product unshippable, he said.

3. How is the root cause of the contaminant found?
Once the contaminant is found, determination needs to be made as to exactly what it is. “In most cases, it will be a metal sliver, not a sphere,” Spurgeon said. So it then may be necessary to use a magnet to determine the type of metal it is, such as stainless, ferrous, etc. “That helps to narrow down the source,” he said. Once the type is known, the source needs to be determined. “It’s time to do some forensics on it,” he said.

In some cases, the contaminant will be large enough to determine what it was or was part of (e.g., a screw, a colored utensil, a stone, etc.). So the next step is determining where it came from. This could be a matter of taking apart any equipment that uses that type of screw, checking that all utensils are whole and accounted for, determining if the contaminant came in with the raw material, etc. If you can identify it, you will have a clue as to the cause, Ries said. “You can then start going upstream to look for the source.”

Subsequent action will be determined by the nature of the foreign material, Anderson said. If the source is of the product itself, such as a bone in meat or stone in beans, “comparison should be made against acceptable standards in terms of either size or frequency,” he said. “There is a high probability that some of each will be in the product, as even the best de-boning and de-stoning operations will yield to the numbers.” If it’s the package, he continued, immediate action should be taken to isolate the product stream, as the likelihood of the contaminant extending into other items is high; if process, it’s likely that it is a machine part and the source must be identified immediately; and if people, “then you have a long-term educational program to review.”

“The end goal is to identify those root causes,” Rogers said. The equipment simply provides the information and data that a contaminant was found. “It’s what we do around it that really makes the difference in the process.”

4. What is done to fix the issue and prevent its occurrence?
Knowing the contaminant and the cause will lead to a means of corrective action and prevention. This is not only replacing and tightening a bolt that fell into the process or checking the rest of a delivery for contaminants, it means taking steps to better maintain and inspect equipment to ensure against other failures, and working with the raw material supplier and/or receiving to better protect against incoming contaminants.

Prevention also requires ongoing equipment maintenance and validation to protect against false negatives. “It’s one thing for a company to have inspection equipment, it’s another thing to prove that it’s working well,” Spurgeon said.

“It’s important to confirm on a very consistent and scheduled basis over the course of a day and week that the [equipment] is performing as expected,” Smith said. To validate this, test wands, cards, or strips are run through the machine at regular intervals, based primarily on the amount of product a company is able and willing to hold. If the system does not detect and reject the card, then every product since the last validation would go into quarantine.

Such validation is not conducted because the equipment is unreliable, but to verify that it is, Pederson said. “For me, the biggest thing is to believe in your device. Have enough confidence in the device that you believe it.”

Validating equipment not only helps to ensure against contaminants and recalls, it provides for documentation should a consumer contact your company saying he or she ingested metal. “It will be your lot to trace back and show that the equipment that was there to protect against that was operational,” Spurgeon said.

A full program. “Physical contamination is one of those things that you can throw a little investment at and solve the problem,” Rogers said. “Having a good system, and a program in place around that system, is one of the things we can have a real impact on today.” But, he added, the real key is identifying the root cause, then determining how to prevent it from happening again.

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