Tuesday, April 22, 2014

National Park Service Proposes New Service Animal Rules

The National Park Service within the Department of the Interior is proposing to define service animals for purposes of specifying when they may be allowed in no-pet sections of national parks. The proposed rules follow the definitions and most of the general requirements of the Department of Justice in public accommodation regulations issued by that agency in 2010.  There have been some interesting refinements, such as allowing a park ranger to require the user of a service dog that is off leash to demonstrate the animal’s recall.  If a supposed service dog is causing difficulties with other visitors to a national park, or with wildlife in the park, the ranger can ask the user of the dog to articulate its function or even demonstrate its work or tasks.  Although there are some difficulties with the demonstration requirement as it might be applied to certain types of trained dogs, the idea that a user should be able to demonstrate control over a supposed service animal is an important development. 

Department of the Interior, National Park Service, Areas of the National Park System; General Provisions, Resource Protection, Public Use and Recreation, Pets and Service Animals; Special Regulations of the National Park System, Olympic National Park, Isle Royale National Park, RIN 1024-AE06, 79 Fed. Reg. 21876 (April 18, 2014).   The Department of the Interior is seeking comments on its proposal, which should be submitted by June 17, 2014. Comments may be easily made on the proposal on the regulations.gov website.  The Department will undoubtedly value the opinions of service dog users who regularly visit national parks.  Comments Dr. J. Lawrence Thomas and I submitted regarding the proposed rules have been posted on the regulations.gov site (Doc. # 2014-08563).

National Park Service Covered by Rehab Act but Not by ADA

The reason for the proposal, according to the April 18 release in the Federal Register, is due the fact that the agency’s regulations on pets have remained unaltered since 1983 despite significant changes in the “federal statutes governing accessibility for persons with disabilities, as well as the use of service animals.”  In other words, it is time for the National Park Service and the Department of the Interior to catch up with other federal agencies that have considered the rights of users of service animals, most particularly the Department of Justice.  The preamble to the proposal states:

“Although the NPS is not governed by the ADA, NPS policy, as expressed in NPS Director’s Order #42, is to align its regulations with the ADA and make NPS facilities, programs, and services accessible to and usable by as many people as possible, including those with disabilities. It is also NPS policy to follow, as appropriate, the DOJ regulations that implement title II and III of the ADA.” 

Despite not being covered by the ADA, the Department accepted in interim guidance issued in 2002 that it was required to admit service animals under the Rehabilitation Act of 1973:

“After careful review of the issues related to the use of service animals in the national parks, and based on the advice provided by the Solicitor's Office, we conclude that we are legally required by Section 504 of the Rehabilitation Act to allow all types of service animals into the parks. The NPS will revise the regulations to adopt a broader interpretation of what a service animal is, and where service animals should be allowed. The NPS will use the same definition of service animal currently found in DOJ regulations (28 CFR36.104). Service animals will not be considered pets and, in general, when accompanying a person with a disability (as defined by Federal law and DOJ regulations), must be allowed wherever visitors or employees are allowed.”

The Department is to be commended, because unlike the Army and the Department of Veterans Affairs, which have given lip service to the ADA while issuing regulations and policies directly contrary to positions taken on the ADA by the Department of Justice, the Department of the Interior has appropriately adapted DOJ definitions for purposes of assuring that individuals with service animals can take maximum advantage of national parks. 

Current Rules on Pets and Guide Dogs

The National Park Service currently defines a pet as “a dog, cat or any animal that has been domesticated.” (36 CFR 1.4)  A series of restrictions apply to pets, including that possessing one “in a public building, public transportation vehicle, or location designated as a swimming beach, or any structure or area closed to the possession of pets by the superintendent” is prohibited. A “superintendent” is someone in charge of a park or an authorized representative of such an official. 

The particular prohibition on pets in a public building, etc., does “not apply to guide dogs accompanying visually impaired persons or hearing ear dogs accompanying hearing-impaired persons.”  (36 CFR 2.15(a)(1)) The phrase concerning guide dogs for the visual or hearing impaired was introduced in the regulations in 1983 (48 Fed. Reg. 30285, June 30, 1983), replacing a reference to “Seeing Eye dogs.” The original 1966 rule had stated:

“Pets are prohibited in public eating places, food stores and on designated swimming beaches at all times.  The Superintendent may also designate the posting of appropriate signs other portions of the park area where pets are not permitted.  This paragraph shall not apply to Seeing Eye dogs.”  (36 CFR 2.8, 31 Fed. Reg. 16652, December 29, 1966).  

This indicates that the burden was originally on a park superintendent to put up signs around a park where dogs were not to be allowed, but that if there were no sign, the pet owner could take the animal into the area.  The original rule also did not provide exceptions for excluding Seeing Eye dogs.  Guide dogs are also specifically mentioned in current rules regarding the Olympic National Park and the Jean Lafitte National Historical Park, where the prohibition of dogs and cats on park lands and trails does not apply to them.  (36 CFR 7.28(c); 36 CFR 7.37(c)). 

As already noted, however, the current regulations do not fully define national park policy as interim guidance issued in 2002 stated that service animals were to be allowed wherever visitors could go in national parks.  The guidance stated:

“[O]ur current regulation (36 CFR 2.15), which recognizes only guide dogs for the blind and signal dogs for the hearing impaired, is unenforceable against persons with disabilities who rely upon service animals for other purposes. Therefore, all park units must immediately expand the definition of service animals to be consistent with the DOJ definition and allow all service animals accompanying persons with disabilities the same privileges currently provided to guide dogs and hearing assistance dogs.”

Nevertheless, the Department wanted to give park superintendents authority to keep even service animals out of areas where their presence might be a risk to visitors or wildlife.  The interim guidance stated:

"[A] superintendent may close an area to all service animals upon an individualized assessment and a written determination that allowance of any domestic animal would pose a direct threat to the health and safety of people or wildlife. This determination must also follow the requirements of36 CFR 1.5/1.7. However, the legal burden is on the superintendent to justify closing an area of the park to service animals accompanying persons with disabilities.”

This is somewhat analogous to Arizona and California laws that allow exclusion of service dogs where they might come in direct contact with zoo animals.  (See Service and Therapy Dogs in American Society, pp. 48-9.)

Golden Access Passports

A special procedure was provided by the interim guidance for individuals seeking a Golden Access Passport, which is an access card “available to United States citizens of any age who have a disability that impairs any life function.”  The 2002 guidance stated:

“In some very limited situations the NPS may require additional procedures to verify that the animal is providing a service for a qualified person with a disability. The NPS already utilizes a procedure to determine if an individual is a qualified individual with a disability for purposes of receiving a Golden Access Passport. That procedure requires either written documentation of a disability or the signing of a statement attesting to having a disability as defined by Federal law. A similar procedure could be utilized with regard to service animals in cases where a superintendent believes it is necessary.”

Any documentation requirement regarding service animals would appear to be inconsistent with the rules now being proposed, as will be discussed further below.

Proposed Modification to National Park Service Rules

In prior rules that referred to Seeing Eye dogs (1966) and “guide dogs accompanying visually impaired persons or hearing ear dogs accompanying hearing-impaired persons” (1983), the terms for specialized dogs were considered self-explanatory and received no listing in the definitional section of the regulations (36 CFR 1.4).  Now, the Department of the Interior proposes to define a service animal as follows:

Service animal means any dog that has been individually trained to do work or perform tasks for the benefit of an individual with a disability, including a physical, sensory, psychiatric, intellectual, or other mental disability. Other species of animals, whether wild or domestic, trained or untrained, are not service animals for purposes of this definition.”  (Proposed 36 CFR 1.4(a))

This follows (except for replacing “is” with “has been”) the definition of the Department of Justice in 28 CFR 35.104 and 28 CFR 36.104. The reference to mental disabilities establishes that the Department of the Interior is following the Department of Justice in recognizing that service animals include psychiatric service animals, though this term for a specific type of service dog is not used in the proposal.   As to the work or tasks of the animal, proposed 36 CFR 2.15(b)(1)(i) elaborates:

“The work or tasks the service animal is trained to perform must be directly related to the individual’s disability. In making this determination, an authorized person may observe the animal and ask if the animal is required because of a disability and what work or task the animal has been trained to perform. Authorized persons must not ask about the nature or extent of a person’s disability, nor may they require documentation of the disability or proof that the animal has been certified, trained, or licensed as a service animal.”

Specifically regarding access, proposed 36 CFR 2.15(b)(1) states:

“A service animal may accompany an individual with a disability in a park area where members of the public are allowed or may accompany an employee with a disability in a park area where employees are allowed.”

The latter clause indicates that the new access policy will apply in the workplace for an NPS employee.  

Emotional Support Animals Are Not Included

Like the Department of Justice, but unlike the Department of Transportation regarding air carrier access, emotional support is not an adequate status to get an animal into a national park:

“The crime-deterrent effects of an animal’s presence and the provision of emotional support, well-being, comfort, or companionship do not constitute work or tasks for the purposes of this provision.”

Again, this follows language in the DOJ definition of a service animal. (28 CFR 35.104) As already noted, a psychiatric service animal is a type of service animal—doing work or performing tasks specifically related to an individual’s mental disability—and is not precluded from entry as an emotional support animal.  Unlike the preamble to the DOJ regulations issued in 2010, however, which included numerous references to psychiatric service animals (75 Fed. Reg. 56267, 56268, 56269, 56271, 56272, September 15, 2010), the preamble to the national park service regulations makes no mention of psychiatric service animals.  Since employees of the National Park Service may not all find the time to read the original releases of the current DOJ regulations, it would be advisable for the Department, when it finalizes the regulations, to distinguish psychiatric service animals from emotional support animals.  This is a distinction that is often confusing to the public—and sometimes even to people who work with service and therapy animals—and there is no reason to expect that NPS employees will not be equally confused unless they are given clear guidance on the matter. 

Service Dogs in Training Do Not Qualify as Service Animals

Service animals in training are, according to the proposed rules, “regulated as pets,” and would thus not have access reserved for service animals. (Proposed 36 CFR 2.15(c))  While this might on occasion exclude an animal that is almost fully trained, it is probably intended to reduce false claims of service animal status.  This would also mean that a trainer of service animals should not consider bringing a service animal to a national park and expect to have the same rights as a person with a disability.  Of course, since there is no certification or training requirement, a service animal that is nearly fully trained should be under the user's control at a sufficient level to provide a demonstration of its function or its obedience level.  

Miniature Horses Sometimes Treated Identically to Service Animals

As did the Department of Justice in 2010, the Department of the Interior now acknowledges that some miniature horses are being trained as guide animals.  Consequently, the superintendent of a park “may allow the use of a miniature horse by an individual with a disability if the miniature horse has been trained to do work or perform tasks for the benefit of the individual with a disability and after observing and assessing the following factors:  (i) The type, size, and weight of the miniature horse and whether the facility can accommodate these features; (ii) Whether the handler has sufficient control of the miniature horse; (iii) Whether the miniature horse is housebroken; and (iv) Whether the miniature horse’s presence in a specific facility compromises legitimate safety requirements that are necessary for safe operation.”

Proof of Certification, Training, or Licensing

As quoted earlier, under 36 CFR 2.15(b)(1)(i) an NPS employee may not require proof that a dog "has been certified, trained, or licensed as a service animal." This language is taken from a provision in the Department of Justice regulations entitled "Inquiries" (28 CFR 36.302(c)(6)).  The Department of Justice elaborated on the reason for this language in the preamble to the final rule (75 Fed. Reg. 56272), stating:

"Certain commenters recommended the adoption of formal training requirements for service animals. The Department has rejected this approach and will not impose any type of formal training requirements or certification process, but will continue to require that service animals be individually trained to do work or perform tasks for the benefit of an individual with a disability. While some groups have urged the Department to modify this position, the Department has determined that such a modification would not serve the full array of individuals with disabilities who use service animals, since individuals with disabilities may be capable of training, and some have trained, their service animal to perform tasks or do work to accommodate their disability. A training and certification requirement would increase the expense of acquiring a service animal and might limit access to service animals for individuals with limited financial resources."

Nevertheless, neither the Department of Justice in its 2010 regulations nor the National Park Service in its current proposal preclude an authorized individual from examining certification, training, or licensing documents if they are proffered by the user of a service animal. This is appropriate, but a caution regarding the significance of such documentation is in order.  Although there are many legitimate training organizations that provide certification documents for dogs they train and sell, it is by now clear that many people are obtaining bogus documents for their pets, generally from websites that sell harnesses, badges, and laminated certification cards.  In 2010, when I was researching Service and Therapy Dogs in American Society, I generally found that bogus documents cost at least $100. A recent search indicates that they can now be obtained for as little as $25.

It is to be hoped that in issuing final regulations, the National Park Service will make mention of the limited value of certification documents in verifying actual service animal status. The National Park Service should also assure that in issuing Golden Access Passports, applicants are not using such bogus documentation to establish that their dogs are service animals. 

Leash or Harness for a Service Animal

Service animals are generally presumed to have to remain beside the person with the disability:

“A service animal must be controlled at all times with a harness, leash, or other tether, unless the restraint device would interfere with the service animal’s safe, effective performance of work or tasks or the individual’s disability prevents using these devices. In those cases, the disabled individual must be able to recall the service animal to his or her side promptly using voice, signals, or other effective means of control. This must be demonstrated when requested by an authorized person.”  (36 CFR 2.15(b)(2))

This is a sensible regulation, and one that should be considered by the Department of Justice, which only specifies that a harness, leash, or other tether is not required if it “would interfere with the service animal’s safe, effective performance of work or tasks, in which case the service animal must be otherwise under the handler’s control (e.g., voice control, signals, or other effective means).”  (28 CFR 35.136(d)) The Department of the Interior’s reference to “recall” is in some ways superior to the DOJ’s wording since it requires that the dog follow a standard command that any animal with a minimal level of obedience training, and certainly a service dog, should instantly be able to demonstrate.  A demonstration that the dog can stay at the user’s side with a “heel” command could show even better that the dog will keep in an appropriate position when off leash.

The preamble also specifies:

“Service animals may not be left unattended, may not make unreasonable noise or exhibit aggressive behavior, and handlers must comply with excrement disposal conditions established by the superintendent. Service animals must be under control at all times while in the park.”  Again, this is a sensible perspective that should generally not present any problem to the user of a true service animal. 

Requirement to Remove an Uncontrolled or Unvaccinated Service Animal

As with the DOJ regulations, there are circumstances when an individual may be required to remove a service animal from a park area:

“An individual may be asked to remove a service animal from an area closed to pets if: (i) The animal is out of control and the animal’s handler does not take effective action to control it; (ii) The animal is not housebroken; or (iii) It is not readily apparent and the individual with a disability is unwilling or unable to articulate or demonstrate the work or task the animal has been trained to perform, consistent with paragraph (b)(1)(i) of this section.”  (proposed 36 CFR 2.15(b)(3)

This generally follows the DOJ requirements (28 CFR 36.136(b)) but, by adding a demonstration requirement, could present certain problems.  For instance, a medical alert or response dog, such as one that alerts and/or responds with tasks to seizures or low-blood-sugar conditions, may be trained to react to a chemical or behavioral change in the owner that the owner would be unable to replicate at will.  For such service animals, it might be preferable to have a somewhat broader requirement allowing the owner to demonstrate the dog’s ability at recall and perhaps one or two other obedience commands, which should make a description of what the dog does during a seizure or episode credible.  The same might be said of autism service dogs that work with children, who may be trained to interfere with certain behaviors of the child which the parents should not have to demonstrate. 

Owners may also be required to remove service animals from specific areas if they cannot provide proof of vaccinations.  (Proposed 36 CFR 2.15(b)(5))  This also is a sensible.  I do not know anyone with a service animal who does not make an effort to keep vaccination records in a wallet or purse.  The preamble states that vaccination records can include, but are not limited to, “rabies, distemper, parvovirus, and adenovirus, and proof of current treatment for intestinal parasites and heart worms.”  Similar proof may be required for miniature horses, which may also be required to show a “negative Coggins test for equine infectious anemia.”  For all these vaccinations and tests, the preamble states:

“An individual could demonstrate proof by showing a copy of a veterinarian bill for the required vaccines and treatments, a state-issued rabies tag, and/or a state health certificate, provided that the state vaccination requirements for the state health certificate mirror those established by the superintendent.”

Closing Areas to Service Animals

Superintendents of parks can make determinations to close areas to service animals for the health or safety of people or wildlife.  Such areas must, obviously, be also closed to pets.  In making such a determination, proposed 36 CFR 2.15(b)(5) states:

“In determining whether the use of service animals poses a threat under this paragraph, the superintendent must: (i) Make a written determination based on objective evidence evaluating the nature, probability, duration, and severity of the threat; and (ii) Explain in the written determination why less restrictive measures will not suffice.”


The National Park Service has clearly labored over the proposed rule changes, and is to be commended for adhering to the approach of the Department of Justice with regard to service animals.  The Service has attempted to provide national park employees with reasonable criteria by which they can distinguish true service animals from pets that aggressive owners want to claim as service animals.  The idea of allowing a demonstration of a response to a recall command for a service animal that is not tethered should be considered by the Department of Justice.  Nevertheless, the possibility of excluding a service animal because the owner cannot demonstrate the animal performing its function should be modified to take into account the fact that some service animals—seizure and hypoglycemia alert and response dogs, and some autism service dogs—may not easily demonstrate what they do when the changes or actions of the owner, or the owner’s child, are not occurring at the moment the request for the demonstration is made. 

Thanks to Leigh Anne Novak and L.E. Papet for comments.  

Additional Note:  The proposed modification of the National Park Service regulations was anticipated by the end of 2015, according to the docket folder on the regulations.gov website, and has not happened. With 68 comments having been submitted, it cannot be argued that public interest was negligible.  That the concept of testing verbal control could be practical is indicated by the Voice and Sight Tag program of Boulder, Colorado, which allows dogs to access "designated trails off leash if they display special participation tags and they are under 'voice and sigh control' of their guardians at all times."  One-hour classes are offered frequently, eight alone in the month of January 2016.  Thanks to Alice Layton for bringing this program to my attention. 

Wednesday, April 16, 2014

Central Police Canine Training Unit in Poland Used for Large-Scale Study of Drug Dogs

Shepherd Working in Unfamiliar Location (courtesy T. Jezierski)
Scientific research is frequently constrained by a laboratory’s funding level and available personnel, as well as such factors as the time limit within which a graduate student must gather data for a thesis.  This often means that the number of animals that can be evaluated is severely restricted to only a few, as can be noted in many studies involving the ability of dogs to detect chemicals, diseases, contaminants, wildlife, etc. 

Instead of bringing a few dogs into the laboratory, Dr. Tadeusz Jezierski and colleagues at the Polish Academy of Sciences were given access to the central canine training unit of the Polish police and gathered an immense amount of data from tightly controlled trials of dogs that had already been deemed fit for field work.  Statistics were gathered concerning 68 dogs and over 1,200 experimental searching tests (517 with Labrador retrievers, 440 with German shepherds, 203 with terriers, and 59 with English Cocker spaniels).

Vehicle Sniff (courtesy T. Jezierski)
This allowed an analysis of the relative effectiveness of specific breeds used by the Polish police (most effective to least: German shepherds, English Cocker spaniels, Labrador retrievers, terriers), and established which drugs are most accurately indicated by the dogs (in order from most easily detected to most difficult: marijuana, hashish, amphetamine, cocaine, heroin).  The trials were run at training centers where the rooms were familiar to the dogs and in stables and storerooms that were not familiar to them.

Many new aspects of working canines came to light while others have been known for years. As an example, contrary to the belief of many police dog handlers, the dogs performed equally efficiently in both known and unknown locations.  It was also possible to determine how long residual drug odors were detectible by dogs working at different types of sites.  As contributors to the study, we are constrained by the Journal’s author agreement in how much we can say here, but the article is now posted on the website of Forensic Science International.   

Jezierski, T., Adamkiewicz, E., Walczak, M., Sobczynska, M., Gorecka-Bruzda, A., Ensminger, J., and Papet, E.  Efficacy of Drug Detection by Fully-Trained Police Dogs Varies by Breed, Training Level, Type of Drug, and Search Environment.  Forensic Science International, 237, 112-118.   

This blog was written by L.E. Papet and John Ensminger.

Thursday, April 3, 2014

Detecting Fecal Contaminants on Produce, a New Occupation for Sniffer Dogs

My wife and I recently flew from Paris to Atlanta.   While we were waiting to pick up our luggage to go through customs, a handler with a beagle began to walk beside the carousel, sniffing bags that had been removed from it by passengers.  I assumed at first the beagle was a drug dog, then noticed the screen suspended above the carousel, which actually showed a short film about the beagle. There was no sound, but the film was subtitled, like a silent movie.  “What is the beagle doing?” the screen asked.  Then there were pictures of various food items—a head of lettuce, a bunch of radishes, a package of meat.  Then X’s crossed out each item to let anyone watching know that these items were forbidden.  The dog was shown sniffing a suitcase and sitting down in front of it and looking at the handler.  The suitcase was then opened by the overly willing passenger (probably an ICE officer in civilian clothes), revealing a bunch of radishes. (Think twice before you try to smuggle radishes from France.) 

Another agricultural use of dogs was recently described in the Journal of Food Protection, and quite likely foreshadows a new industry for dog trainers and handlers. 

Fecal Contamination of Produce

Microbes, such as Escherichia coli, Salmonella, and Listeria, can get onto fresh produce through feces of rodents, birds, and other animals.  The feces can be put directly on the produce by the animals or can be brought into a field or factory through irrigation or processing water.  A group of researchers from the School of Veterinary Medicine at UC Davis and from various facilities of the U.S. Food and Drug Administration have published a paper analyzing how effective dogs might be in detecting fecal contamination of produce.  

The team had three dogs trained for the experiments, all mixed-breed females.  Dog 1 and Dog 2 were given what was called “indirect detection training,” under which the target scent was a sterile gauze pad saturated with a mixture of feces and water.  The feces were collected from vertebrate species commonly found in or near agricultural fields, specifically dog, cow, horse, black-tailed deer, feral pig, coyote, Canada goose, sheep, and human. Dog 1 and Dog 3 were given “direct detection training,” under which dogs were trained to recognize fecal contamination of romaine lettuce, spinach, cilantro, and whole Roma tomatoes placed in specimen storage containers.  Thus, Dog 1 received both types of training, but Dogs 2 and 3 only received one or the other. 

Indirect Detection Trial Procedures

In the indirect detection trials, lettuce, spinach, cilantro, or tomatoes were put into 30 bags, and 8 of those bags were filed with either 0.025, 0.25, 2.5, or 25 grams of feces (two bags at each amount).  Gauze pads were suspended were suspended by strings were suspended inside the bags but not in contact with the produce for 24 hours.  The gauze pads, which were 4-ply cotton pads, were removed after a day and separated to create separate samples. The samples included gauze pads from bags in which there was no fecal contamination.  Samples were placed in special holders in three rows of 10, with contaminated samples distributed randomly. Trials were double blind as the dogs, the handler, and the data recorder did not know which samples had pads with fecal contamination.  The handler made sure the dog examined each holder.  For each alert, the dog was rewarded with some time with a chew toy.  Care was taken to remove secretions—at least obvious secretions—by dogs sniffing close to holders. 

Direct Detection Trial Procedures

For direct detection trials, 8 of 30 bags of produce had feces added, but in amounts of 0.0025, 0.025, 0.25, or 2.5 grams.  After the first trial, the largest amount was dropped and an even smaller amount, 0.00025 grams was added.  Instead of three rows of ten, as in the indirect detection trials, there was one row of 12 containers, which were different than those used in the indirect detection trials and had holes drilled in the top shortly before a trial began.  To avoid rewarding the dogs for an incorrect response (which had been possible in the indirect detection trials), the dog was praised verbally for an alert during the direct detection trials.  

Indirect Detection Results

In the indirect detection trials, Dogs 1 and 2, the ones used in these trials, missed detecting fecal contamination in most samples where the gauze had been exposed to fecal contamination.  Dog 1 was nearly twice as effective as Dog 2 in alerting to pads from samples that had fecal contamination, but also alerted more often to pads that had not been in bags with fecal contamination.  Both dogs were more likely to detect fecal contamination on Roma tomatoes than on cilantro or spinach.  When the produce in a bag was contaminated with 2.5 grams of feces, the highest possible amount, both were considerably more accurate.  However, the results indicated that this procedure, as conducted in the experiment, was not effective.  

Direct Detection Results

When dogs were able to sniff the produce itself, as opposed to a gauze pad that had been kept near the produce for 24 hours, they were much more accurate.  This is not surprising as there was presumably a higher odor concentration using this approach.  Here, each dog sniffed 720 containers, 156 of which contained some amount of feces.  The researchers found that “Dogs 1 and 3 had 11.1 and 23.6 higher odds of alerting, respectively, when encountering treatment samples compared with control samples.”  Dog 1 was significantly more likely to incorrectly alert in the presence of a control sample than was Dog 3. 

The amount of fecal contamination proved to be crucial.  When the amount of contamination was greater than 0.025 grams, the probability of detection achieved 75%, and reached almost 100% at 2.5 grams: 

“In other words, for samples with ≥0.025 g fecal contamination, the probability of collecting samples of produce with fecal contamination is 5- to 30-fold higher (500 to 3,000%) when using a dog than when randomly selecting produce samples across a field, as is sometimes done during investigations.”

Implications for Agricultural Inspections

The advantage of the indirect detection approach was that vegetables were not exposed to the dog, which prevented cross-contamination between the dog and the sample.  The researchers note that unfortunately this approach “did not result in acceptable levels of sensitivity for any but the highest levels of fecal contamination.”  The direct approach was more successful, in that the dogs exhibited 76% and 86% sensitivity, respectively, in detecting more than 0.25 grams of fecal contamination.  (For an explanation of the terms “sensitivity” and “specificity,” see a prior blog on the use of dogs to detect lung cancer.)

California Ground Squirrel
Ground squirrels, common in produce fields, defecate between 2% and 8% of their body weight per day.  The researchers state that, based on their results, “scent detection dogs might be able to detect as little as 1% of a ground squirrel’s daily fecal load if deposited on, for example, spinach or cilantro or after foliar irrigation when feces or scat are deposited in furrows and along beds of leafy greens.” 

The broader implication of this is stated as follows:   “A protocol that uses a fecal scent detection dog to first screen all produce samples and then test only those to which the dog alerted can increase the probability of detecting contaminated produce by up to 3,000%, depending on the background prevalence of fecal contamination in the field.”

The researchers conclude that “the use of scent detection dogs will allow us to prioritize produce samples for analytical testing and thereby optimize the detection of both feces and the associated microbial pathogens that so often accompany fecal contamination.” 


The results achieved with the dogs might be improved by different training regimens, or the use of different breeds, possibilities that the researchers concede may be true. Using dogs over longer periods than was the case with these experiments might also improve accuracy. 

The dogs were not as accurate as some prior research found in other contexts, but context is important.  Researchers looking to use dogs in cancer detection have insisted on consistently high success rates before this application can move into clinical environments, but the same levels of success should not be required for using dogs in detecting fecal contamination of produce.  If it can be verified that a protocol involving canine screening of samples, in order to prioritize which truckloads or other units of vegetables should receive further testing, would increase the probability of detecting contaminated produce by up to 30 times over the present approach, this makes a strong case for implementation despite the fact that some contaminated lots would still be missed.   

It is to be hoped, therefore, that if these results are verified, detection dogs may soon be put into service in real-world commercial agricultural operations.  Another example of such a use of dogs might be in detecting oil in fish hauls after a spill.  A new canine industry may be in the offing.

Partyka, Melissa L., Bond, Ronald F., Farrar, Jeff, Falco, Andy, Cassens, Barbara, Cruse, Alonza, and Atwill, Edward R.  (2014).  Quantifying the Sensitivity of Scent Detection Dogs to Identify Fecal Contamination on Raw Produce.  Journal of Food Protection, 77(1), 6014.  

This blog was written by John Ensminger and L.E. Papet.