Kong as a Detection Odor: Are We Thinking Critically?

The use of Kong as a detection odor has become almost a standard in many training programs. It’s copied, repeated, and promoted—often without trainers truly questioning what they’re doing and why. But if we take a deep dive into this discussion, we can quickly identify the pitfalls of this method. As trainers, our job isn’t to blindly follow trends, but to think critically about our goals and choose the best approach to achieve them—efficiently and effectively. This means questioning what we’ve been taught, adapting when needed, and staying true to our integrity. I’ve used Kong. I’ve used many different approaches. And through real-world experience, I’ve found that Direct Odor Imprint (DOI) is the most effective way to train detection dogs. But my goal here isn’t to tell you to follow my method—it’s to encourage you to think. What is your goal? And is your method truly the best way to get there?

The K9 industry needs honest conversations, not marketing gimmicks

Real progress doesn’t come from social media hype, clever branding, or recycled training theories wrapped in a new name. It comes from honest conversations, real-world experience, and trainers who dare to think outside the box. But here’s the problem: too many so-called “big names” in the K9 world aren’t interested in improving training. They’re interested in clicks, controversy, and profit. They tell you what you want to hear, fake results, and build their brands on personality—not principles. They sell you on methods as if they just invented them. Instead of helping trainers solve real challenges, they focus on creating loyalty to their brand. They don’t want you to think—they want you to follow.

Follow principles, not personalities

One of the biggest problems in the K9 training world right now is that trainers are following people instead of principles. Just because someone has a big name doesn’t mean they have big knowledge. The best trainers aren’t the loudest voices in the room—they’re the ones who keep learning, keep questioning, and keep improving for the sake of the dogs and the industry. So here’s my challenge to you: think critically. Don’t follow methods just because they’re popular. Don’t trust trainers just because they have a big following. Ask yourself: does this method truly serve my dog, my goals, and my integrity? That’s how we move forward—not by following trends, but by thinking for ourselves.

Where did the Kong method come from?

The Kong training approach is a perfect example of how a method can be repackaged and sold as something “revolutionary”—even when it wasn’t new at all. Let’s be clear: this was never an original invention of the trainers now promoting it. Long before they put their name on it and started selling courses, the Norwegian People’s Aid (NPA) and the Norwegian military had already been using this method. They developed it for practical reasons, not because it was the “best” detection method, but because it fit their operational needs. Yet, instead of analyzing its strengths and weaknesses, some trainers later took this existing idea, repackaged it, and marketed it as a groundbreaking scientific discovery. But here’s the reality: the Kong method started in 1992, when the NPA launched its demining program in Cambodia. Over the past three decades, they have worked in 45 countries, clearing explosive remnants and training detection dogs. They chose to imprint their dogs on Kong odor for very specific operational reasons:

• Availability – Kong toys are easy to obtain.
• No legal restrictions – Unlike explosives or narcotics, Kong doesn’t require a license to use.
• Travel flexibility – Kong odor can be transported freely, even on airplanes.

For their environment, this choice made sense. But was it the best detection training method overall? That’s a different question—one that many trainers failed to ask before blindly adopting it.

I saw this method firsthand when I visited the Norwegian Army K9 school in 1997. I was curious, so I trained some dogs with this approach, studied the mechanics, and conducted my own experiments. Then, I brought the idea back to the Dutch K9 police school in Nunspeet. Their response? Laughter and resistance. And why? Because the Dutch police had access to real operational odors, so using a piece of Kong made no sense to them. They didn’t need a synthetic or placeholder odor—they could work directly with what the dogs would actually encounter in the field. This is exactly why we, as trainers, must think critically instead of just following trends. What works in one context isn’t necessarily the best solution for another. Good training starts with understanding the “why”—not just copying what everyone else is doing.

Stainless steel pipes as a training method

The method used in the Dutch police at that time was nothing new—it had already been in use for over 50 years. The approach was simple but effective: select dogs with extreme drive—so strong that they were willing to chase and retrieve stainless steel pipes with enthusiasm. Once this drive was conditioned, imprinted the metal pipes with the target odor by placing them in a sealed glass jar with, for example, explosives. The training followed a clear progression:

• Initial Association – Dogs were first rewarded for chasing and retrieving the metal pipes.
• Odor Imprinting – The pipes were stored with the target odor, allowing them to absorb scent molecules.
• Simple Searches – The scented pipes were placed in sight for the dog to find.
• Advanced Searches – Pipes were hidden out of sight, reinforcing the dog’s need to detect the odor to locate its reward.

The advantage of using stainless steel pipes was that they easily attracted and held onto odor molecules. Plus, they could be thoroughly cleaned and reused, and they could introduce non-scented pipes to teach the dog that only the correct odor triggered play. While this method produced highly effective detection dogs, it required skilled handlers and trainers who understood the mechanics of drive-building and precise odor imprinting. And, especially today, there’s a bigger challenge: finding enough high-drive dogs that are crazy enough to chase and play with stainless steel pipes.

Did the Dutch police change their training approach?

It took the Dutch police nearly 20 years to reconsider the Kong method. The turning point came in 2017, when I introduced them to the FBI’s electronic detection dog program. I had visited Special Agent Calandra at the FBI Academy in Quantico, Virginia, where I saw firsthand how they trained dogs to detect electronics. Back in the Netherlands, I was working as a trainer/operator in a covert unit and quickly realized that we didn’t have this skill in our own Dutch K9 program. So, I arranged a management meeting with the Dutch police K9 school, proposing we work together to develop this capability. Graham Attwood from UK, who was working with Calandra, was invited by Adee Schoon in a second meeting with a lot of trainers to explain all the details. We designed a training plan based on Calandra’s and Graham's ideas, but one thing surprised me: the new generation of Dutch police trainers wanted to start with pieces of Kong, pairing them with electronic odors. Something had clearly changed in the last 20 years. The experienced trainers still held on to the metal pipe method, relying on their operational experience and the logic of “if it works, why change it?” But the new generation of trainers had fully embraced Kong—without being able to explain exactly why. Was it because they wanted recognition for introducing a new approach? Were they influenced by YouTube videos and trends? Or was it simply because the Kong method is easier to understand and apply than the metal pipe method?

There are some undeniable practical advantages to using Kong:

• More dogs are willing to play with a Kong than a metal pipe.
• The training concept is easier to teach and replicate.
• There’s no need to handle real illicit substances, reducing risks and paperwork.
• No cleaning, no impregnation process, no strict record-keeping.

With Kong, everything is simpler. And maybe that’s exactly why it became popular. But does simpler always mean better? That’s the real question trainers should ask themselves.

Why I stopped using Kong as a detection odor

Whatever the reason for the shift to Kong was, it happened gradually over 20 years. But what surprised me most was that no one in the Dutch police ever talked to me about the problems with this method. I had encountered numerous issues with Kong that made me question its effectiveness as a detection odor. Some of the biggest challenges included:

• Longer training time – The pairing process added unnecessary steps.
• Overshadowing issues – Dogs could focus more on the Kong than the actual target odor.
• Proofing difficulties – Once conditioned, removing Kong odor from a dog’s search behavior was nearly impossible.
• False alerts – My dogs alerted on pieces of Kong left behind by other trainers.
• Odor inconsistency – Old and new Kong toys had noticeable odor differences.
• Operational risks – A Kong-trained dog could cause major security incidents in real-world settings like airports by falsely alerting on harmless Kong toys.
• -Overpowering odor – Kong’s strong scent made training too easy, spoiling dogs and reducing their ability to detect more subtle odors.
  

These issues led me, 20 years ago, to develop the Direct Odor Imprint (DOI) method—a system where dogs are imprinted on the target odor from the very beginning. DOI provides a clear, structured, and effective way to train detection dogs to identify and discriminate between specific odors without unnecessary distractions. The results? Thousands of trainers and dogs trained, real-world operational success, and stunning outcomes. For me, that was more than enough reason to leave Kong behind.

What is your goal?

In detection dog training, keeping your goal in focus is everything. When designing a training plan, you need to think critically—not just about what works, but also about what could go wrong. Murphy’s Law applies here: if something can go wrong, it eventually will. Are you following the crowd, or are you thinking critically? Are you building a rock-solid detection dog that can handle real-world challenges? For me, training an operational detection dog on Kong odor is a risk I’m not willing to take. Why? Because in real-world scenarios—like working at an airport—there’s a high chance that a traveler will have a Kong toy in their luggage. A false alert in that situation could cause unnecessary delays, security concerns, or even legal issues. But in other contexts, using Kong might not be a problem at all. If you’re training in a post-war zone like with NPA, the chances of encountering Kong toys are minimal, so it’s not an issue. In fields like wildlife detection, medical detection, sport scent work, or nosework, a false alert on Kong is inconsequential—you can simply move on. But now, think about a law enforcement scenario. Imagine standing in court, raising your hand, and swearing under oath that your dog has never been trained on any odor other than narcotics, explosives, or whatever substance it alerted on as evidence. Could you say that with 100% certainty? If your training history includes Kong, would you be willing to bet your reputation, the case, or someone’s future on it? That’s why your goal matters. And that’s why choosing your training methods wisely is critical.

I don’t mind what odor you use—but I do mind if you can’t explain It

Whether you train your detection dog with a Kong, a tennis ball, a towel, or any other item, that’s your choice. But if you are a professional detection dog handler, you should be able to explain why you use a specific item and fully understand the risks involved. And if you can’t convince me—or better yet, show me—that your dog will completely ignore these items in an operational double-blind setting, then I do mind.

Quality, testing, and science

Beyond setting clear training goals, we also need to test our dogs, trainers, and handlers properly. While we have strict calibration and testing protocols for mechanical and electronic detection equipment, the standards for deploying detection dogs are often far less rigorous. So how do we truly determine if a dog is ready for operational work? And how can we collect data in an objective way? Much of the testing in the K9 world is biased. Take Kong, for example. We know that one piece of Kong is not the same as another. Some trainers cut them to specific weights and sizes, others boil them before use. Some handle them with gloves, while others don’t. Some add specific human scents. Odor off-gassing varies depending on environmental conditions. There are countless variations in how trainers handle odor materials, and even more questions that scientists would demand answers to. If we want to move forward as an industry, we need to ask these questions before blindly following trends.

Sniffing frequency: science vs. operational reality

Some of the biggest names in the K9 industry advocating for the Kong method have never actually worked in real-world operations. And let’s be honest—the operational world is nothing like a controlled backyard brick wall setup or a neatly arranged lineup of objects. One of the arguments I often hear in favor of using small pieces of Kong is that it increases the dog’s sniffing frequency. Yes, a high sniffing rate is important because that’s how dogs bring odor to their nose and into their olfactory system. But let’s be real about what that means in practice. This concept might work well in a laboratory setting, but in real operations, it’s simply not sustainable. Sniffing at a high rate for extended periods is exhausting for a dog. A detection dog working in a real-world environment—whether searching a vehicle, a cargo hold, or a large building—needs to pace itself to last an entire shift, not just a few minutes.

Real operations last hours, not minutes

My missions lasted for hours, not minutes. When I worked with top trainers and scientists in the U.S. military, we discussed the need for training programs that produced dogs capable of working for extended periods—not dogs that burned out after a few short searches. Military working dogs protecting soldiers on eight-hour missions are trained in a way that aligns more with their natural hunting instincts. This is where I believe trainers sometimes lose sight of the bigger picture. We focus so much on learning theory like classical and operant conditioning that we forget to look at natural animal behavior.

Have you ever seen a hunting dog sniffing at high frequency on a tiny section of a bush? Of course not. If a dog used that strategy in the wild, it would take ages to find prey. Instead, dogs use a more efficient, natural searching pattern that balances energy and effectiveness. Now imagine applying the “high-frequency sniffing only” approach to operational detection work. If a dog needs 20 to 30 minutes just to search two suitcases, how is that practical? It simply isn’t. That’s not an effective detection dog—it’s an inefficient one.

Training must be goal-oriented

Detection training should always be designed with the end goal in mind. A detection dog isn’t a science experiment—it’s a working partner. The real question isn’t just whether a method increases sniffing frequency. The question is: does it build a dog that can work reliably, efficiently, and effectively in real-world conditions? If the answer is no, then we need to rethink the method.

Primary and secondary reinforcers

If we go back to the root of why dogs work for us and truly understand the difference between primary and secondary reinforcers, it becomes clear why keeping them separate is important. I believe a dog works for me because of our relationship and the fact that I provide the primary reinforcer in exchange for their work. But when the target odor itself becomes a primary reinforcer, I lose a critical tool in my training. When everything is going smoothly, I don’t need a lot of different techniques. But when I encounter distractions, false alerts, or training challenges, I need the ability to break the process down into small steps. If I can separate the reward from the target odor, I have more flexibility to shape behavior and correct issues.

Mental state and expectation

There has been extensive research on the cognitive abilities of dogs. Take, for example, the famous dog Chaser, who demonstrated an ability to form mental imagery when hearing words. While this concept hasn’t been fully explored in relation to odor detection, I am certain that mental processes play a key role in how dogs perceive scent. This is where Matching Law and mental imagery become important. If a dog is conditioned to associate Kong odor with reward, what happens when they receive a search cue? Instead of focusing on the actual target odor, the dog may mentally fixate on Kong, essentially “seeing” a flying Kong in its mind. If the dog has been exposed to thousands of Kong repetitions during training, this mental image may overpower the actual target odor—whether that be explosives, narcotics, or another operational scent. That’s a serious problem.

Science vs. anecdotal claims

Despite what some claim, there is no solid scientific research proving that Kong is the best training method. What we mostly see is anecdotal evidence—trainers saying it works without backing it up with controlled studies. At the same time, there is a significant body of research on odor carriers, scent soaks, and the differences between real and pseudo-odors—all aimed at improving the K9 community. That is the science I follow. The Norwegian People’s Aid (NPA) started using Kong in 1992 for practical, operational reasons, not because it was the most scientifically sound training method. That distinction is important. I choose to follow scientific research and real-world experience, rather than getting caught up in a trend that lacks true validation.

A Scientifically Grounded Alternative: TraceOdor™

TraceOdor™ is a standardized training odor system developed to bring greater consistency, control, and objectivity to detection dog training. It is built on a simple but important principle: before we ask a dog to detect explosives, narcotics, firearms, wildlife, or any other operational target odor, we should first teach the dog how to detect.

Over more than 25 years of operational K9 work, I have learned that reliable detection is about much more than recognizing a particular odor. It involves independent searching, discrimination, concentration, motivation, and the ability to communicate a clear and reliable indication. These are behaviors we can train, measure, and improve before introducing operational target odors.

That is exactly why I developed TraceOdor™.

Unlike traditional training odors such as Kong, which contain complex mixtures of natural and synthetic rubber compounds that may vary between products and manufacturing batches, TraceOdor™ provides a controlled and standardized odor reference specifically designed for detection training.

The system consists of six carefully defined concentration levels, allowing trainers to develop a dog's detection performance progressively. We can start with relatively accessible concentrations and systematically introduce more challenging detection tasks as the dog's skills develop.

But TraceOdor™ is about much more than odor concentration.

It provides a common reference for training, testing, and evaluating detection dogs. By combining standardized odor materials with structured training protocols, objective observations, and data collection, we can begin to answer important questions. Is the dog actually detecting the target odor? Is the indication reliable? Can the dog discriminate between target and non target odors? How does performance change when odor availability decreases? And perhaps most importantly, are we measuring the dog's detection ability or unintentionally measuring the handler's influence?

These are the questions that should drive professional detection dog training.

TraceOdor™ is produced through a controlled system with batch traceability. Through our Certified Exchange Program, certified bottles are replaced with new bottles from controlled production batches rather than being refilled under uncontrolled conditions. This helps maintain consistency and accountability throughout the system.

For me, TraceOdor™ represents an important step toward a more transparent, measurable, and scientifically grounded approach to K9 detection training.

Real Target Odor or TraceOdor™?

When starting a detection dog, I believe there are two excellent options. We can introduce the operational target odor directly, using a structured approach such as Direct Odor Imprint (DOI), or we can begin with TraceOdor™ to establish the fundamental detection behaviors before introducing operational odors.

Both approaches have their place. The right choice depends on the dog's future role, the trainer's experience, and the objectives of the training program. One important consideration is that odors can acquire emotional and behavioral significance through learning. Just think about how the smell of a dentist's office can immediately trigger a particular feeling or memory. Dogs also develop associations through their training experiences. When we introduce a young dog to narcotics or explosives, we are not simply teaching odor recognition. We are establishing a learning history associated with those particular odors. This becomes especially relevant for organizations that train and evaluate dogs before knowing their final operational destination. What happens when a dog trained on narcotics does not complete the program? Or when a dog originally selected for explosives detection turns out to be better suited for another discipline?

With TraceOdor™, we can avoid introducing operational target odors too early while still developing and evaluating the dog's detection skills. The dog learns the principles of detection, develops confidence, and establishes reliable search and indication behaviors. Once its future operational role has been determined, the training can progress to the actual target odors. Of course, successful performance with TraceOdor™ does not automatically mean a dog will recognize explosives, narcotics, or other operational substances. Those odors must still be introduced, trained, generalized, and validated independently. And that distinction is essential. TraceOdor™ is not intended to replace operational target odor training. It is designed to provide a reliable foundation before that stage begins.

Pretraining: A Game Changer for Professional K9 Organizations

For companies and organizations that select, develop, and supply detection dogs, TraceOdor™ offers a different way of approaching pretraining.

Instead of immediately imprinting dogs on specific operational odors, we can first build the behaviors that every detection dog needs, regardless of its eventual specialization. Independent searching, odor discrimination, systematic problem solving, reliable indication, and the ability to work under increasingly challenging conditions can all be developed within a structured TraceOdor™ training program. Because the system uses a dedicated standardized training odor, we can also reduce unnecessary exposure to operational substances during the early stages of training.

Imagine a company developing twenty young detection dogs for different clients around the world. Some may eventually work in explosives detection, others in narcotics, firearms, electronics, conservation, or medical detection. Rather than making those decisions at the beginning, the company can use TraceOdor™ to develop and evaluate the dogs against a common training reference. This creates opportunities to compare performance, identify individual strengths and weaknesses, and make better informed decisions about each dog's future.

The same principle applies to government agencies and operational K9 units. When a replacement detection dog is needed, an animal that has already developed reliable search and indication behaviors can begin training on the required operational target odors without having to learn every fundamental detection behavior from the beginning.

That does not eliminate the need for operational training or certification. But it can make the transition more structured and potentially more efficient.

Six Concentrations, One Common Reference

One of the most important features of TraceOdor™ is the availability of six standardized concentration levels.

This allows us to introduce progressively more challenging odor detection tasks while collecting meaningful performance data. But I want to emphasize something here. Lower odor concentration does not automatically mean better detection training. Odor availability is influenced by many variables, including temperature, airflow, humidity, containment, surface interaction, and presentation. That is why protocols matter. The real value of TraceOdor™ lies in combining controlled odor materials with consistent presentation methods, careful observation, and objective evaluation. By using blind and double blind testing, we can reduce the risk of unconscious handler cues, sometimes referred to as the Clever Hans effect.

We can measure correct indications, misses, false alerts, response latency, and performance across different training conditions. And instead of relying on statements such as "I think this dog has a great nose," we can begin to build an actual performance profile based on observable behavior. This also makes TraceOdor™ valuable for evaluating handlers and training programs. If different trainers use the same standardized odor reference and comparable protocols, their results become easier to interpret and discuss. Of course, meaningful comparisons still require appropriate control of the many other variables involved.

From Training Equipment to a Complete Learning System

TraceOdor™ is not simply another bottle of training odor that I want to sell.

It is part of a broader approach to detection training that I have been developing throughout my career. The system integrates with our ACT! training equipment, including Odor Delivery Devices, ACT! Stands, and other tools designed to improve odor presentation, training consistency, and objective observation. Every TraceOdor™ purchase also includes access to our online training course, where I explain how to work with the system and develop detection behaviors through structured exercises. In addition, TraceOdor™ users can become part of the TraceOdor™ Community, where trainers can exchange experiences, discuss protocols, share results, and continue learning from one another.

Through the TraceOdor™ Certified Exchange Program, users can exchange an empty certified bottle for a new bottle from a controlled production batch. This supports product traceability and helps prevent the inconsistencies associated with uncontrolled refilling. My ambition is not to convince everyone to use one particular training method. I have never believed in one universal method that works for every dog, trainer, or operational situation. My ambition is to give trainers better tools to understand what they are doing, why they are doing it, and whether it actually works.

The Future of Detection Training

I believe the future of professional detection dog training should be built on transparency, scientific principles, reliable training materials, objective testing, and measurable performance.

Not assumptions. Not traditions that nobody questions. And certainly not impressive demonstrations that tell us very little about what the dog has actually learned. TraceOdor™ is my contribution to that development. A standardized training system designed to help us teach, observe, measure, and compare detection behaviors before moving into specific operational applications. It does not replace real target odors. It does not eliminate the importance of experience, good timing, careful observation, or professional judgment. And like any training system, its effectiveness must ultimately be demonstrated through reliable performance data and independent validation. But it gives us something valuable: a common starting point. Because in the end, I am not interested in simply training dogs to find odors. I am interested in understanding how dogs learn, how we can improve their performance, and how we can make detection training more reliable, efficient, and honest. That is the philosophy behind TraceOdor™.

And that is why I developed it.