How These Technological Advancements in Detection of Foreign and Extraneous Material in Food Can Help You

Gary C. Smith, Colorado State University

USDA’s FR, HACCPS began with the intent of identifying and then controlling three kinds of hazards. Physical hazards took a third seat because we were told that, of all foodborne illness incidents/outbreaks, 94% of the causes were biological, 4% were chemical, and 2% were physical.¹

Justifiably, food safety professionals focused on microbiological and chemical contamination because of the severity of those hazards on private and public health.² The focus has shifted dramatically over the past decade, largely because of the frequency with which presence of foreign and extraneous material (FEM) causes recalls, product withdrawals, safety alerts, consumer complaints, and economic losses.²

A 2017 analysis of combined FDA and USDA recalls revealed that the Top 3 causes were: (1) undeclared allergens, (2) wrong ingredients, and (3) FEM.³ By 2019, it was reported that: (a) FEM had surged to become the No.1 cause of recalls in recent years,⁴ and (b) FEM contamination accounted for 75% of the total volume of food recalled by FSIS.⁵

Why Have FEM Recalls Increased So Dramatically?

It’s a combination of:

1. FDA mandated the listing of FEM Recalls in a Reportable Food Registry.⁶
2. An FSIS Rule requiring 24-hour notification of FEM contamination.⁷
3. The requirement to notify FSIS if the company received consumer complaints about FEM.⁸
4. Lower tolerance for FEM by customers and consumers.²
5. The litigious nature of FEM.²

FEM Contamination the Leading Cause of USDA Recalls in Q1-2019

Plastics were the most common contaminate, being found in 40% of recalled products; millions of pounds of food became landfill or was rendered.⁹ For the expanded period of November 2018 to April 2020, there were at least 23 USDA or FDA FEM recalls. Six of those recalls originated from consumer complaints, including the three largest ones:

1. Tyson Foods™, 11,829,517 pounds of chicken strips;¹⁰
2. Con Agra™, 276,872 pounds of chicken and turkey bowls;¹¹
3. Johnsonville™, 95,393 pounds of sausage.¹²

For 16 of the 23 recalls, a specific FEM was called-out; 7 said “plastic,” 5 said “rubber,” 2 said “metal,” and 2 said “choking hazard.”¹³ (Both FDA and USDA allow front-of-packaging labeling, warning that a bottle-cap or product-size poses a choking hazard.)

What Foreign and Extraneous Matter is Contaminating Food the Most?

FEM recalls of USDA-regulated product (2017 through 2020) were identified as follows:

1. Foreign matter
2. Extraneous material
3. Glass; glass fragments
4. Metal; metal fragments
5. Small rocks
6. Wood
7. Pieces of bone material
8. Rubber; rubber pieces; flexible pink rubber
9. Plastic; soft purple plastic; thin blue plastic pieces; hard green plastic; clear pliable plastic, hard plastic; styrofoam^{13, 14}

Tools to Prevent Foreign and Extraneous Matter from Contaminating Food

With all these recalls and economic losses, we must admit that we’re doing something wrong – or not doing enough. Too many fish are slipping through the net.

There’s no question that “Prevention” (i.e. keeping FEM out)^{15, 16}, “Best Practices”⁴, FMPP/FMCPP^2,17 and developing the right “culture”^{18, 19, 20} are essential, but “Detection And Removal” prevents entry of FEM-contaminated products into commerce.

Ways to “Sort or Remove” FEMs

A compilation of “Things That Sort Or Remove” FEMs by FDA, USDA, BRC, and SQF^{1, 6, 21, 22, 23} lists the following:

• Visual inspection
• Magnet
• Screen
• Sifter
• Riffle board
• Bone separator
• Filter
• Sieve
• Stone trap
• Gravity separation
• Fluid bed technology
• Floatation chamber
• Washing steps
• Small parts test fixture used for toys

“Things That Detect” Foreign and Extraneous Matter

A compilation by FDA, USDA, BRC, and SQF^{1, 6, 21, 22, 23} lists the following:

• Metal detector
• X-ray equipment
• UV-light equipment
• Laser equipment
• Optical sorting equipment

As FEM has surged to become the No. 1 cause of recalls, equipment manufacturers have reacted by increasing the precision and accuracy of detection and/or removal of FEM by their x-ray, magnetic, sensor, vision, and imaging instruments.⁴

Tips for Developing a Foreign Material Prevention Program (FMPP)

When you develop a Foreign Material Prevention Program (FMPP), start by determining whether you are purchasing FEM (in the raw materials) or creating FEM (during manufacturing); this will determine where you should place technology-based detection systems.²

Most customers require location of a detection instrument (usually a metal detector or x-ray instrument) at the last point in the processing or manufacturing chain – just before it is finally prepared for shipment to the retailer.

Determine the Origin of the Foreign or Extraneous Matter

In-plant inspection to determine the origin of FEM includes the following:

1. Examine FEMs using appropriate forensic tools like microscopes and x-ray fluorescence.
2. Establish whether the source is internal or external to the plant.
3. Determine where the FEM enters product flow.
4. Identify the means by which the FEM entered the contaminated products.
5. Redesign the process to eliminate the root cause and implement systems to manage the risk.²⁴

Identify the Type of FEM

Identifying the type of FEM is the first step; the Reading Scientific Services Ltd. (RSSL) in the United Kingdom uses the following:

• Light microscopy (for general morphology).
• X-ray microfluorescence (for types of glass, steels, and other alloys).
• Scanning electron microscopy (SEM) with energy dispersive x-ray spectroscopy (EDS) (for even the smallest FEMs).
• Fourier transform infrared spectrometry (FTIR) (for organic materials like fibers and polymers).^{7, 25}

The Food Industry Needs Next-Generation Detection Equipment

The food industry has used visual inspection, sieves, screens, magnets, and metal detectors for decades; but it is low-density FEM (e.g. blue gloves, combo liners, belting, ear plugs, hair nets, labels) that now so often elude detection. So, next-generation detection equipment (using high-definition color-based technology and x-ray technology) are now being used to augment our ability to detect FEM in our food.²⁶

Most food processing facilities use one or more of the five primary detection methods:

1. X-ray
2. Metal detection
3. Optical sorting
4. Magnets
5. Sieve or screen separation systems

The biggest problem? Plastic – especially soft, rather than hard, plastics because none of those five detection methods is really very reliable for detecting small pieces of it.¹⁸

Risk is not a “Yes” or “No” question.²⁷ Certain FEMs present more of a problem than others; some can be found readily through technology, while for others, like thin clear plastics, it’s going to be very difficult.²⁷ The 2019 Tyson™ recall of almost 12 million pounds of chicken strips was a result of the use of metal detectors that were unable to detect tiny particles of stainless steel that originated from wire conveyor belts.²⁸

These Companies are Using New Tools with Great Success

Sorters, filters, sieves, and magnets are typically used with fruits, vegetables, liquids, and powders.⁷ A second, more sophisticated sorting level uses cameras, lasers, plus infrared (IR) and ultraviolet (UV) radiation; cameras look at color and shape, while lasers, IR, and UV analyze reflections (e.g., UV detects the chlorophyll in feces).⁷

Although it occurs very rarely, line-workers have been known to “get even” with supervisors or the company by intentionally putting FEM in food products.²⁹ Company culture should encourage employees to be vigilant – “if you see something, say something.”

Cognex Corporation™, using as few as five images and the In-Sight 2800^® series vision system as a classifying tool, can quickly be trained to identify and sort defects into different categories.³⁰ Cantrell•Gainco™ has introduced a new Foreign Material Inspection System^® that uses color-based inspection technology to find low density FEM like blue gloves; combo liners; plastic and polymer belting material; O-ring ear plugs; as well as beard and hair nets.³¹ P&P Optica™ Vision-Based Detection Systems^® use multi-spectral vision to see 15 colors – including white paper, white cotton gloves, or clear plastic; it’s hyperspectral can be taught “what to look for” using artificial intelligence, operating on the production-line in real time.⁵

The Top FEM-Control Technologies

In an article entitled “Getting Rid of Just Enough,” Pan Demetrakakes said, “In-line inspection systems have to reliably weed out FEM contamination and defective product without being too finicky. The goals of quality-control inspection systems are simple; find stuff in the product that’s not supposed to be there, and get rid of it – while getting rid of as little product as possible.³²

Top technologies for FEM control identified by two experts are the following:

(a) Sorters, filters, and magnets

(b) Cameras, lasers, and IR/UV radiations

(c) Metal detectors and x-ray systems

(d) Updated versions of metal detectors (e.g., use of 5-voltage frequencies at once) and x-ray systems (e.g., using multiple beams and imaging software)⁷

The Limitations of Metal Detectors for Identifying FEMs

Metal detectors can be flummoxed by “product effects” and odd shapes (e.g., long, thin ones or very tiny particles).³² Metal objects change the electromagnetic field and generate a voltage signal in FEMs. In x-rays, foreign objects with higher density will attenuate more energy, producing a darker area in the image.⁷ The detection capability of both systems is limited by the so-called “product effect”, which can cause false positives or negatives.⁷ In metal detectors, “product effect” is the phenomenon whereby the product and the contaminate generate a similar signal at the same frequency.⁷

These Improved Metal-Detection Technologies are Helping Food Safety Professionals

Improved technologies for metal detection include the following:

• Fortress™ Interceptor Divergent Field^® inspects low profile (e.g., slices of cheese and deli meats) vertically and horizontally to achieve the highest possible sensitivity. It is especially sensitive to small, very thin metal contaminant flakes and foils that are very difficult to detect on low profile foods.^{33, 34}
• Mettler-Toledo Safeline™ Signature^® systems find ferrous and non-ferrous tramp metal, non-magnetic stainless steel, non-spherical fine-wire fragments, plus it creates a memory storage bank. On production lines where multiple different kinds of food are produced, the memory storage bank rapidly accounts for differences in “product effect.”³⁵
• Eriez Manufacturing™ produces magnetic separators (for tubes, grates, traps, etc.) and Xtreme Metal Detectors™ that use “rare earth magnets” to generate the greatest known “pull strength” to remove micron-sized ferrous material particles, rust, fine stainless steel, aluminum, and brass from food products.^{34,36, 38, 39} The Xtreme Metal Detector™ incorporates Enhanced Platform technology, which allows it to account for “product effect.”³⁷
• ABM Equipment™ is using new hardware and software from Eagle™ to detect FEM in food products half the size previously possible; it can detect FEM fragments as small as 0.3mm (0.117 inch).⁴⁰
• ThermoFisher Scientific™ Selectscan® can find metal objects that are 25% smaller than previous technology. Autolearn™ in Selectscan® rapidly identifies the ideal frequency (from 50 to 1,000 kHz) to maximize probability of detection, tunes out “product effect”, and adapts results to account for temperature changes and electromagnetic interference.⁴¹

Improved Technologies for Non-Metallic FEM Detection

Technologies for non-metallic FEM defects include the following:

• Eagle Product Inspection™ offers RMI 400®, an advanced x-ray inspection machine that detects contaminants that include bone, stainless steel, aluminum, glass, and stone.⁴²
• Sesotec™ offers RAYCON® x-ray scanners that detect magnetic and non-magnetic metals, glass, ceramic, stone, raw bones, and several types of plastics. ⁴²
• Mettler-Toledo™ offers an x-ray Reinspection Program® that allows food companies to reinspect quarantined product without shutting down ongoing production; after initial detection, the x-ray system can be configured to maximize detection for that particular contaminant.⁴³
• Colorado State University researchers and JBS-USA are conducting trials on an OXOS™ hand-held, radioactive imaging detection apparatus that is portable and can be used to identify sources of FEM anywhere and everywhere food travels during processing.⁴⁴
• Eagle Product Inspection™ has developed Pack 400 HC with PXT®, which detects bone fragments down to 1mm.⁴⁵
• Mettler-Toledo™ Safeline® now has Model X33 and Model X36 x-ray scanners that multi-task for manufacturers of packaged goods; metal detectors just detect metal (and reject packages wrapped in foil). These x-ray scanners detect all FEMs, don’t reject packages that have a foil component, and check each package for fill volume.⁴⁶

Of interest is that most manufacturers of dairy novelties use x-ray scanners rather than metal detectors because, over the years, fruit pits and nut shells remain the most prevalent consumer complaints, insects are second, and glass and stones are common.⁴⁷

“Elastomers” (i.e., springy, resilient, flexible rubber or plastic materials used to close or connect crevices or connections in a series of pipes or tubes) and rubber that provide elasticity to gaskets, O-rings, screens, sheets, and scrapers, degrade over time. As a result, rubber/elastomer fragments often enter food streams and are missed by metal detectors and x-ray inspections. Rubber Fab™ makes Detectomer Products® which, as “Detectomer fragments”, can be blended into the other components used to manufacture gaskets, O-rings, etc., thereby making the fragments detectable by x-ray and metal detectors.⁴⁸

Prepare for Pre-Pandemic Recall Levels

There was a pronounced decline in recalls in 2020 and 2021 due to the COVID-19 pandemic. FDA recalls averaged 607 between 2015 and 2020, 389 in 2020 and 342 in 2021.⁴⁹ USDA recalls averaged 130 between 2015 and 2020, 31 in 2020, and 45 in 2021.⁴⁹

With regulatory scrutiny set to increase in 2022 and beyond, food processors should anticipate a return to pre-pandemic recall volumes.⁴⁹ On average, the cost of a food safety recall is going to be anywhere from $10 to $30 million; some exceed hundreds of millions of dollars.⁵⁰ There is also the potential harm to the consumer in the form of illness or possibly even death.⁵⁰

Food companies like Sysco™ factor into their earnings projections, Reputational Risk (damage to their brand), Legal Risk (litigation costs), and Shareholder Risk (declines in publicly traded stock value) of potential recalls.⁵⁰ In today’s food processing environment we’re also seeing individuals being held criminally liable for food safety recalls.⁵⁰

FSNS offers a full range of analysis for foreign and extraneous matter in food, while Certified Laboratories, our partner company under the Certified Group umbrella, specializes in food forensics and filth testing.

References

1. Pawluczyk, Olga. 2021. Food Quality & Safety. July Edition.
2. FSPC Alliance. 2016. Preventive Controls For Human Foods. First Edition.
3. Tolu, Andrea. 2020. Food Quality & Safety. November Edition.
4. Belk, Keith. 2022. Colorado State University. August 24 Issue.
5. McCarthy, Ryan. 2019. Meat + Poultry. June 6 Issue.
6. McCarthy, Ryan. 2019. Meat + Poultry. May 6 Issue.
7. Keefe, Lisa. 2020. Meatingplace. May 25 Issue.
8. McCarthy, Ryan. 2019. Meat + Poultry. June 3 Issue.
9. Smith, Gary. 2021. Texas A & M University. May 16 Issue.
10. Smith, Gary. 2021. Texas A & M University. February 8 Issue.
11. Butts, John. 2018. Food Safety Magazine. September Edition.
12. Seyfert, Mark. 2021. Food Safety Magazine. June 17 Issue.
13. Sims, Bob. 2021. Meat + Poultry. September 16 Issue.
14. Williamson, Sherry. 2020. Food Safety Magazine. November Edition.
15. Jesperson et al. 2020. Food Safety Magazine. March Edition.
16. Sharman, Nic. 2021. Food Safety Magazine. August 22 Issue.
17. BRC.2017. Implementing BRC Standards. August Edition.
18. SQF. 2014. Implementing SQF Standards. May Edition.
19. Smith, Gary. 2018. FSNS: HACCP Compared To PCHF Class. March Edition.
20. Henderson, Matt. 2020. Meatingplace. June Edition.
21. Wright, David. 2020. Food Quality & Safety. November Edition.
22. Cantrell•Gainco.2020. National Provisioner. September Edition.
23. Davis, De Ann. 2020. Food Quality & Safety. November Edition.
24. Finstad, Suzanne. 2022. MeatingPod. July 20 Issue.
25. Gibson, Kate. 2022. Meatingplace. August 29 Issue.
26. Food Quality & Safety. 2022. July Edition.
27. Gibson, Kate. 2021. Meatingplace. August 13 Issue.
28. Demetrakakes, Pan. 2020. Food Processing. May Edition.
29. Johnston, Tom. 2021. Meatingplace. August 4 Issue.
30. Food Quality & Safety. 2022. July Edition.
31. Bissell, Hadley. 2022. Food Processing. August Edition.
32. Laughman, Casey. 2020. Food Engineering. August 27 Issue.
33. Stevens Strategic Communications. 2021. October 12 Issue.
34. Laughman, Casey. 2021. Food Engineering. September 21 Issue.
35. Food Processing. 2022. July 26 Issue.
36. Cassa, John. 2021. Dairy Processing. June 1 Issue.
37. Food Engineering. 2020. November 6 Issue.
38. Food Safety Magazine. 2018. March Edition.
39. Food Safety Magazine. 2020. September Edition.
40. Belk, Keith. 2022. Colorado State University. August 17 Issue.
41. Food Processing. 2022. July Edition.
42. Food Processing. 2020. February Edition.
43. Putch, Kristen. 2021. Dairy Processing. July 1 Issue.
44. Food Safety Magazine. 2018. September Edition.
45. Ricci, Peter. 2022. Meatingplace. February Edition.
46. Barr, Brian. 2022. Food Processing. August Edition.