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REVIEW
Raw diets for dogs and cats: a
review, with particular reference to
microbiological hazards
R. H. D,* J. R. L† A. D. W1,‡
*Department of Bacteriology and Food Safety, Animal and Plant Health Agency (APHA – Weybridge), Addlestone, KT15 3NB, UK
†Department of Epidemiological Sciences, Animal and Plant Health Agency (APHA – Weybridge), Addlestone, KT15 3NB, UK
‡Department of Pathology and Infectious Diseases, School of Veterinary Medicine, Faculty of Health and Medical Sciences, University
of Surrey, Guildford, GU2 7AL, UK
1Corresponding author email: a.wales@surrey.ac.uk
There is a recent trend to feed pet dogs and cats in Britain and other developed countries on raw meat
and animal by-products using either commercial preparations or home recipes. This shift from heat-
treated processed food has been driven by perceived health benefits to pets and a suspicion of indus-
trially produced pet food. The diets of wild-living related species have been used as a rationale for raw
feeding, but differences in biology and lifestyle impose limitations on such comparisons. Formal evi-
dence does exist for claims by raw-feeding proponents of an altered intestinal microbiome and (subjec-
tively) improved stool quality. However, there is currently neither robust evidence nor identified
plausible mechanisms for many of the wide range of other claimed benefits. There are documented
risks associated with raw feeding, principally malnutrition (inexpert formulation and testing of diets)
and infection affecting pets and/or household members. Surveys in Europe and North America have
consistently found Salmonella species in a proportion of samples, typically of fresh-frozen commercial
diets. Another emerging issue concerns the risk of introducing antimicrobial-resistant bacteria. Raw
pet food commonly exceeds hygiene thresholds for counts of Enterobacteriaceae. These bacteria often
encode resistance to critically important antibiotics such as extended-spectrum cephalosporins, and
raw-fed pets create an elevated risk of shedding such resistant bacteria. Other infectious organisms
that may be of concern include Listeria, shiga toxigenic Escherichia coli, parasites such as Toxoplasma
gondii and exotic agents such as the zoonotic livestock pathogen Brucella suis, recently identified in
European Union and UK raw pet meat imported from Argentina.
Journal of Small Animal Practice (2019)
DOI: 10.1111/jsap.12300
Accepted: 8 March 2019
PRACTICE, RATIONALE AND MOTIVATION FOR
RAW FEEDING
Feeding products containing raw meat to dogs and cats has
become markedly more popular in recent years among pet own-
ers in many developed countries. A large, structured, 2016 sur-
vey in the USA indicated that 3% of dog and 4% of cat owners
reported purchasing raw pet food, and raw or cooked human
food was purchased for pets by 17% of dog owners (APPA 2018).
Objective survey data for Europe is lacking, but business and
expert opinion indicates similar substantial and growing raw-
feeding practices in the UK (Waters 2017).
Raw meat-based diets (RMBDs), sometimes marketed as
“Biologically Appropriate Raw Food” or “Bones and Raw Food”
(BARF) diets, include uncooked ingredients from either livestock
or wild animals and may be home-prepared or commercial, with
the latter being supplied as fresh, frozen or freeze-dried complete
diets or as premixes intended to be complemented by raw meat
(Freeman et al. 2013). Raw feeding was given momentum by
non-specialist publications in the 1990s and early 2000s (Bill-
inghurst 1993, Freeman & Michel 2001, Towell 2008) that
http://www.bsava.com/
R. H. Davies et al.
2 © 2019 Crown Copyright. Journal of Small Animal Practice published by John Wiley & Sons Ltd on behalf of British Small Animal Veterinary Association.
advanced the idea of a more “natural” diet for pet dogs and cats.
Claimed benefits, compared with conventional processed diets,
are wide-ranging and include improved dental and skin health,
prevention or control of disorders affecting any of the major body
systems, and behavioural improvements (Towell 2008, Freeman
et al. 2013, Natures:menu 2017, BARF World 2018).
It has been proposed (Freeman et al. 2013) that feeding
RMBDs answers a psychological desire among owners to care
for and improve their pet’s health, using a route that is simple
and understandable, compared with more challenging and con-
fusing interventions associated with health professionals. There
is also an anti-establishment tone to some articles promoting
RMBDs, including sentiment directed against “conventional”
pet food manufacturers and the veterinary mainstream (BARF
World 2018). Recent survey work comparing attitudes between
RMBD- and conventional-feeding pet owners supports the idea
that RMBD-feeding owners are less engaged with health special-
ists (Morgan et al. 2017).
EVIDENCE CONCERNING THE BENEFITS OF
RAW FEEDING
The wolf has been used as a model by proponents of raw feed-
ing, and much has been made of its limited capacity to digest
the carbohydrate that forms a substantial part of conventional
dog food. However, the domestic dog is genetically altered from
its wild ancestors, with increased starch-digesting capacity owing
to different patterns of gene expression (Freeman et al. 2013).
Other differences between domestic and wild canids include the
balance between energy and other nutrient needs, plus longevity
(Kölle & Schmidt 2015). These further highlight the limitations
of attempting to closely model domestic carnivore diets on those
of their ancestral wild counterparts. Furthermore, the relevance
of diets eaten in the wild to the health and longevity of domestic
and captive mammals may be challenged more broadly. Indeed,
contemporary expertise in feeding zoo-kept canids, including
wolves, emphasises the benefit of using conventional processed
dog food for the majority of the diet (AZA Canid TAG 2012).
A small number of studies have been conducted in an endeavour
to provide a verifiable evidence base for some claims made for raw
feeding. Faecal bacterial diversity appeared to be higher among six
raw-fed dogs compared with five fed conventionally processed food
in a metagenomic study (Kim et al. 2017). A small feeding trial
of boxer dogs comparing raw high-quality beef plus supplement
with a commercial dry diet and including metagenomic analysis
reported smaller, firmer stools and changes (of unclear signifi-
cance) in the faecal bacterial community (Sandri et al. 2017). Kit-
tens raised on a rabbit-based raw diet also had better stool quality,
assessed with a visual grading system, than their commercial diet-
fed peers, but both groups grew similarly (Glasgow et al. 2002).
Another cat-feeding trial compared a commercial raw diet, a
supplemented raw chicken diet and a tinned diet (Hamper et al.
2017). Kittens of sequential litters from the same two parents grew
similarly on any of the diets, clinical pathology analyses showed
minor variations, and diarrhoea was encountered with both raw
and cooked diets. Similarly, diarrhoea was neither positively nor
negatively associated with raw feeding among dogs used to assist
health care (Lefebvre et al. 2008). This same, year- long, study
noted significantly fewer episodes of extra-intestinal infectious
disease among raw-fed dogs, but this was a secondary focus, using
owner-reported data and with a modest number (38) of cases. No
significant difference was seen for non-infectious disease.
A critical review by Schlesinger & Joffe (2011) concluded that
the evidence advanced for the many claimed health benefits of
raw feeding amounted to opinions and claims that were, at best,
supported by data that was of low relevance. Claims for improved
oral health in diets with raw bones find support in studies show-
ing less calculus among feral or wild dogs and cats yet, on bal-
ance, the limited published evidence does not support claims
of reduced periodontal disease with raw feeding (Steenkamp &
Gorrel 1999, Fascetti 2015).
Therefore, aside from some plausible claims for better digest-
ibility and stool quality, the various health claims made for raw
feeding remain a mixture of anecdote and opinion, not backed by
highly relevant data. This situation is reflected in critical reviews
and in advice provided by professional bodies (Schlesinger & Joffe
2011, American Veterinary Medical Association 2012, Freeman
et al. 2013, World Small Animal Veterinary Association 2015).
CONTROLS ON SOURCE MATERIALS AND
PROCESSORS
Source animal species for raw pet foods appear to be diverse
(Weese et al. 2005, Mehlenbacher et al. 2012, van Bree et al.
2018). Commercial compounders and suppliers of raw pet food
in the European Union (EU) are subject to regulations governing
(among other things) animal products not intended for human
consumption, principally Regulation (EC) No 1069/2009. Types
of these by-products that are permitted in pet food fall into the
“Category 3” classification and include those that are fit for, but
not intended for, human consumption. Human food containing
animal products but removed from the food chain for various
reasons (from which no risk to public or animal health arises) can
also be classified as Category 3 material (European Commission
2018). In addition, certain by-products that are unfit for human
consumption are permitted, provided that the animal was slaugh-
tered in a slaughterhouse and was considered fit for slaughter for
human consumption following an ante mortem inspection (or the
animal was a game species killed for human consumption) and
that post mortem examination did not find evidence of communi-
cable disease (Regulation (EC) No 1069/2009; PFMA 2017). In
practice, many producers restrict their animal by-product sources
to those fit for human consumption.
EU Animal by-product regulations require commercial pro-
ducers to perform sampling for Salmonella and Enterobacteria-
ceae according to a site-specific protocol based on batch size and
throughput; in the UK, this is in agreement with the Animal
and Plant Health Agency (APHA). Detection of any Salmo-
nella in samples of product means that it cannot be placed on
the market. In the UK, such a finding necessitates notification
Raw feeding dogs and cats
© 2019 Crown Copyright. Journal of Small Animal Practice published by John Wiley & Sons Ltd on behalf of British Small Animal Veterinary Association. 3
of the Local Authority and APHA, with the latter supervising
the recall and disposal of any affected product, a clean-down of
facilities, investigation of the cause and increased frequency of
testing (PFMA 2017). In England, there is a derogation allow-
ing animal by-product producers to supply unprocessed material
(fit but not intended for human consumption, suitably handled
and recorded) direct to individual consumers without being reg-
istered or regulated as pet food establishments.
As an example of controls in a major territory outside the EU,
microbiologically contaminated animal food is prohibited in
interstate commerce in the USA, and Food and Drug Admin-
istration advice is for meat ingredients for raw pet food to have
been passed for human consumption (Center for Veterinary
Medicine 2004). It has been asserted by the American Veterinary
Medical Association (2012) that “Raw pet foods are produced
with little to no regulatory oversight by the state or federal gov-
ernments,” although the Food Safety Modernization Act of 2011
has gradually introduced further regulation of the pet food sec-
tor, with an emphasis on hazard identification and prevention.
Nonetheless, derogations exist for small businesses allowing for
self-declaration of hazard analysis and preventive controls, with-
out mandatory verification of effectiveness by testing (Center for
Veterinary Medicine 2016).
RISKS OF RAW FEEDING
Nutrition
Investigations of both home- and commercially prepared raw diets
commonly have identified nutritional problems, such as calcium/
phosphorous imbalances and specific vitamin deficiencies (Free-
man & Michel 2001, Freeman et al. 2013). Moreover, homemade
diets are inherently susceptible to nutritional imbalances and defi-
ciencies (Towell 2008). Such diets may be constructed from reci-
pes that do not have verifiable origins in nutritional expertise and
feeding studies. Indeed, commercially available raw diets are com-
monly formulated without the benefit of feeding studies (Mehlen-
bacher et al. 2012). Owners can also be tempted to simplify recipes
(Kölle & Schmidt 2015), and ingredients may be poorly defined
in the recipe, locally unavailable or of varying quality. There are
a few case report studies of clinical nutritional disease associated
with raw feeding (Schlesinger & Joffe 2011, Lenox et al. 2015).
In the absence of feeding studies for many (if not most) raw
diets compounded to be nutritionally balanced, issues of bio-
availability pose a further risk of deficiency (Fascetti 2015). This
was illustrated starkly in a study using a whole-rabbit raw diet
that contained adequate taurine on analysis yet still resulted in
taurine-deficiency cardiomyopathy (causing a fatality) among
young cats after some months of feeding (Glasgow et al. 2002).
Bacterial pathogens
The bacteriological quality of raw commercial pet foods, assessed
by total bacterial, coliform or E. coli counts, has been noted to fail
threshold levels for raw human meat products in a high proportion
of sampled foods in both Europe and North America (Freeman &
Michel 2001, Weese et al. 2005, Kölle & Schmidt 2015, Nilsson
2015, van Bree et al. 2018). This, combined with the presence of
certain pathogens or antimicrobial-resistant bacteria (summarised
in Table 1), poses risks of colonisation and disease for owners and
pets alike. It has been noted by researchers sampling raw pet foods
from commercial outlets that package warnings about preparation
and hygienic handling of these pet foods are commonly absent
(Finley et al. 2006, Strohmeyer et al. 2006, Mehlenbacher et al.
2012, Bojanic et al. 2017, van Bree et al. 2018) and that packag-
ing may be defective and leaky (Bojanic et al. 2017).
Salmonella
The transmission of Salmonella to dogs and their owners via
contaminated treats, conventionally processed dry food and raw
diets has been observed in a small number of well-investigated
incidents (American Veterinary Medical Association 2012; Beh-
ravesh et al. 2010; Brisdon et al. 2006; Clark et al. 2001; Cobb &
Stavisky 2013; Health Canada 2000; Mayer et al. 1976; MDH
2018; Schnirring 2018). Transmission to humans from pet food
and treats may be direct in some cases (Pitout et al. 2003), and
the handling of Salmonella-positive food is a well-established risk
factor for human salmonellosis (Cobb & Stavisky 2013). How-
ever, contact with pets has also been identified as a route or a
risk factor for human salmonellosis in several case reports and
studies (Finley et al. 2006, Domingues et al. 2012, Freeman et
al. 2013), indicating that pets which have consumed Salmonella-
contaminated feed also pose an infection risk to owners.
Surveys of raw pet foods in North America (generally frozen and
obtained through commercial outlets) have reported proportions
of Salmonella-positive samples ranging between 7.1% (Strohm-
eyer et al. 2006), 8% (Nemser et al. 2014), 9% (Mehlenbacher et
al. 2012), 20% (Weese et al. 2005) and 21% (Finley et al. 2008).
In contrast, just one of 480 (0.2%) conventionally processed dog
food samples yielded Salmonella in a study from the USA (Nem-
ser et al. 2014). A recent study in the Netherlands reported Sal-
monella isolation from 20% of 35 commercial raw food samples
(van Bree et al. 2018), while in Italy, pork and chicken mate-
rial available for pet food manufacture yielded Salmonella from
12% of samples (Bacci et al. 2019). Surveillance of Salmonella
contamination in pet food by the APHA in the UK (under ani-
mal by-products regulations) reported isolations from raw versus
processed food in ratios of approximately 6:1 in 2015 and 20:1
in 2016, despite most samples coming from the larger processed
food sector (APHA 2017). A higher prevalence of Salmonella in
raw versus processed dog and cat foods was also reported in Egypt
(Azza et al. 2014). Serovars isolated in studies and surveillance
of ingredients and raw food for pets or working dogs are diverse
(Strohmeyer et al. 2006) and include those considered to be of
particular significance for human salmonellosis (Chengappa et al.
1993, Finley et al. 2008, Mehlenbacher et al. 2012, Bacci et al.
2019). Indeed, in recent years in the UK, more than 50% of such
regulated serovar isolations in animal feeding stuffs came from
raw pet food, including tripe (APHA 2016, 2017).
Where pet food is contaminated, likely routes of infection
for pet owners include contact with the food (when preparing
and clearing up pet meals), direct contact with the pet (e.g. from
R. H. Davies et al.
4 © 2019 Crown Copyright. Journal of Small Animal Practice published by John Wiley & Sons Ltd on behalf of British Small Animal Veterinary Association.
Table 1. Summary of literature cited in “Bacterial Pathogens” section
Organism and
references
Details Sampling detail (number of
sampled units)
Detection and identification Principal findings, including % samples positive
Coliforms
Weese et al.
(2005)
Canada CPF, raw, frozen and freeze-dried
(25).
Cult., Sero. Coliforms: mean 106 cfu/g†. E. coli: 64%. Salmonella: 20%. Clostridium
perfringens: 20%. Cl. difficile 4%. Staphylococcus aureus 4%.
E. coli
Bacci et al.
(2019)
Including ESBL. Expired
human food. Italy
Poultry (52), pork (30) and beef
(30), potentially for raw CPF.
Cult., Sero., PCR (ESBL genes) E. coli: 98% samples, MDR in 48% of 110 isolates. Salmonella: 13% pork, 12%
poultry, 0% beef; of 10 isolates, 80% serovar Typhimurium, 70% MDR, 40%
ESBL pheno- and genotype.
van Bree et al.
(2018)
Including O157:H7,
ESC. The
Netherlands
CPF, raw frozen (35). Cult. (bacteria), PCR (protozoa
detect.)
E. coli: 86%, mean 9×102 cfu/g. O157:H7: 23%. ESC: 80%. Salmonella: 20%.
Listeria monocytogenes: 54%. Toxoplasma gondii: 6%. Sarcocystis species:
23%.
Byrne et al.
(2018)
Tracing from four linked
human STEC O157
cases. England
CPF and ingredients, raw: cases’
freezers (2), linked producer (1)
and supplier (1).
Cult., PCR, genome sequencing. STEC: multiple PCR-positive samples from one home and linked producer.
STEC O100:H30 from latter. Outbreak isolate not recovered, but much STEC
contamination.
Nilsson (2015) Including ESC. Sweden CPF, raw frozen (39). Cult., PCR (typing) E. coli: 49% > 5×102 cfu/g‡; 5%>5×104 cfu/g; ESC: 23% blacmy2.
Azza et al.
(2014)
Egypt Pet food: raw (20), not raw (40). Cult. E. coli: 35%. Salmonella: 5%. S. aureus: 15%. All from raw.
Nemser et al.
(2014)
O157:H7 and STEC,
USA
CPF: raw (196), dried treats (190),
not raw (480).
Cult., PCR (STEC) No O157:H7. Raw (mostly frozen): STEC 4%, Salm. 8%, Listeria species 33%, L.
monocytogenes 16%. Dry: STEC 1.1%, Listeria species 0.5%. Not raw: Salm.
0.2%, Listeria greyii 0.2%.
Lenz et al.
(2009)
O157, USA Pet dogs (91), 42 raw-fed, matched
faeces and food.
Cult., Sero. E. coli O157: No isolations. Salm.: 14% raw-fed dogs, 5% raw food samples; no
other isolations. Campylobacter jejuni: 1 isolation from raw-fed dog.
Lefebvre et al.
(2008)
Including ESC. Health
care assistance
dogs, Canada
Dogs (194), 40 raw-fed raw. Faeces
and nasal swabs, bi-monthly for
1year.
Cult., Sero. Point prevalence ranges (% dogs): ESC E. coli (AmpC-type) raw 15 to 45 versus
non-raw 0.9 to 9.7; Salm. raw 2.5 to 25 versus non-raw 0 to 2.6. VRE: 1
isolate; ESBL no isolations. All dogs shedding Salm. >1 occasion were raw
fed. MRSA and Cl. difficile: no association with raw feeding.
Strohmeyer et
al. (2006)
USA CPF, raw frozen (240), not raw (48). Cult. (bacteria), PCR (protozoa
detect.)
E. coli: 60% raw, 33% dry, 8.3% canned. Salmonella: 7.1% raw, Cryptosporidium:
0.8% raw, 4% canned.
Freeman
& Michel
(2001)
O157:H7, USA CPF, also home-made and meat
plus additive, all raw (5).
Cult. One E. coli O157:H7 isolate, no Salmonella.
See also Weese et al. (2005) (under “Coliforms”)
Salmonella
MDH (2018) Link to human Salm.
Reading cases, USA
CPF, raw, ground turkey (1). Cult. Salmonella Reading (1/1).
Reimschuessel
et al. (2017)
Laboratory
submissions, USA
Pet dog (2422) and cat (542)
stools, 50% diarrhoeic.
Cult., Sero. Raw-fed dogs over-represented among Salmonella-positive cases (P=0.03,
multiple regression). Cats rarely Salmonella positive.
Kantere et al.
(2016)
Greece Dogs (120), 60 raw-fed; oral plus
faecal swabs.
Cult., Sero. Salmonella only from raw-fed dogs (18%). Various serovars, antimicrobial
resistances common.
Mehlenbacher
et al. (2012)
USA CPF: raw frozen (29), dehydrated
and freeze-dried (31), not raw (5).
Cult., Sero. 14% of frozen raw, four serovars.
Leonard et al.
(2011)
Canada Pet dogs (138), 28 raw-fed. Faeces,
5 consecutive days.
Cult., Sero. 50% raw-fed dogs versus 16% not raw-fed; raw feeding only significant risk
factor for shedding in series of univariable models.
Behravesh et
al. (2010)
Investigation of human
cases, USA
Faeces of cases’ pet dogs (≥15),
dry dog and cat food (multiple),
feedmill samples.
Cult., PFGE S. Schwarzengrund of outbreak PFGE pattern isolated from six of 15 dog stool
samples and four brands of dog and cat food from same feedmill, plus one
location within the mill. Mostly young children infected, risk factor of feeding
pet in kitchen in univariable case-control study.
Finley et al.
(2008)
Canada and USA CPF, raw frozen (166). Cult. 21%, up to five serovars per sample, some multi-resistant. Chicken-containing
diets more likely (5×) to yield Salmonella.
Finley et al.
(2007)
Naturally contamin-
ated raw food.
Faeces, 16 experimentally fed
dogs. Daily sampling.
Cult., Sero. Seven dogs shed Salmonella, for range 1 to 11 days. Two of these shed a
serovar different from that isolated from the food.
Brisdon et al.
(2006)
Trace-back from three
human cases
Dog treats, link to cases by brand
or premises.
Cult., PFGE Indistinguishable subtypes of S. Thompson from humans and pet treats in all
cases.
Raw feeding dogs and cats
© 2019 Crown Copyright. Journal of Small Animal Practice published by John Wiley & Sons Ltd on behalf of British Small Animal Veterinary Association. 5
Table 1. (Continued)
Organism and
references
Details Sampling detail (number of
sampled units)
Detection and identification Principal findings, including % samples positive
Morley et al.
(2006)
Dog kennels,
salmonellosis. Food
mixed on site. USA.
Food in bowls (3), frozen beef (18),
environment swabs (31), dog
faeces (61).
Cult., Sero., PFGE Isolates from 100% food in bowls, 33% beef, 93% faeces, 48% swabs.
Predominantly S. Newport including all meat isolates. Multiple subtypes,
overlap between beef, faeces and environment isolates.
Weese &
Rousseau
(2006)
Bowl hygiene study
using spiked food.
Swabs, after contamination of bowl
surfaces and drying.
Cult. Proportion of bowls with viable Salmonella Copenhagen after: 7days (100%),
85 °C dishwasher cycle (67%) or scrubbing with soap (79%) followed by
bleach soak (42%).
Pitout et al.
(2003)
Link to human cases in
ESC Salm. cluster
Dog treat: dried beef (1). Cult., Sero., PFGE ESC, PFGE pattern identical to some and similar to others from human S.
Newport ESC cases.
Joffe &
Schlesinger
(2002)
Food and recipient dog
study. Canada
CPF: raw chicken-based (10) and
not raw (10). Dog faeces (20).
Cult., Sero. Food, raw: 80%, various serovars. Faeces, raw-fed, 30%. No other isolations.
Clark et al.
(2001)
Canada Treats: pig ear (265), other (39). Cult., PFGE, PT Pig ears: production plant 29% and retail 51%. Other treats: 38%. Several
serovars.
Hea (2000) Trace-back from human
case. Canada
Pig ear treat from linked premises. Cult., PFGE, PT S. Infantis: same serovar, phage type and PFGE pattern as human case.
Mayer et al.
(1976)
Raw-fed police dogs,
Germany
Faeces, dogs (67), three occasions. Cult. First sampling: 42% shedding Salm. Thereafter, diet was cooked, but 69% dogs
fed raw offal by handlers. Second sampling: 55% shedding, more serovars
reflecting local pig carriage.
See also Weese et al. (2005) (under “Coliforms”); Bacci et al. (2019), van Bree et al. (2018), Azza et al. (2014), Nemser et al. (2014), Lenz et al. (2009), Lefebvre et al. (2008), Strohmeyer et al.
(2006) and Freeman & Michel (2001) (under “E. coli”)
Campylobacter
Bojanic et al.
(2017)
New Zealand CPF, raw (50); rectal swabs, dogs
(90), cats (110).
Cult., PCR (speciation), MLST. Campylobacter species: food, 28%; dogs 36%; cats 16%. C. jejuni: food 22%;
dogs 13%; cats 5%; several MLST types shared between food and pets.
See also Weese et al. (2005) (under “Coliforms”); Lenz et al. (2009) and Strohmeyer et al. (2006) (under “E. coli”)
Yersinia enterocolitica
Bucher et al.
(2008)
Germany Faeces, various species; pig
tissues (tonsil, edible offal, pork),
other livestock tissues.
Cult., PCR (detection) Tissues, culture: pig offal 51%, pork 9.6%. Tissues, PCR: pork 8.3%, sheep
tonsil 3%, poultry 1%, game 38%. Faeces, PCR: dog 5%, cat 3%.
Fredrikkson-
Ahomaa et
al. (2001)
Biotype 4/O:3 isolates
study, Finland
Faeces: dog (12) and cat (4). Pig:
abattoir (75) and retail (41).
PFGE PFGE patterns of dog and cat isolates, including known raw-fed animals, overlap
with those from pig-derived food.
Brucella suis
Frost (2017) Netherlands and UK Raw frozen hare meat, imported
from Argentina for pet food.
Technique(s) not described Identified following trace-back from B. suis infection of raw-fed dog in
Netherlands.
Listeria See Azza et al. (2014), Nemser et al. (2014) and van Bree et al. (2018) under
‘E. coli’
Staphylococcus aureus See Weese et al. (2005) under “Coliforms”; Lefebvre et al. (2008), Azza et al.
(2014), Nemser et al. (2014) and van Bree et al. (2018) under “E. coli”
Enterococcus species (VRE) See Lefebvre et al. (2008) under “E. coli”
Clostridia See Weese et al. (2005) under “Coliforms”; Lefebvre et al. (2008) under “E.
coli”
CPF commercial pet food, Cult. culture, ESBL extended-spectrum beta-lactamase producer, ESC extended-spectrum cephalosporin-resistant, Incl. including, MDR multi-drug resistant (resistant to ≥3 antimicrobial drug classes), MLST multi-locus
sequence typing, MRSA methicillin-resistant Staphylococcus aureus, PCR polymerase chain reaction, PFGE pulsed-field gel electrophoresis, PT phage typing, Sero. serotyping, STEC shiga toxigenic E. coli, VRE vancomycin-resistant enterococci
†Exceeding Canadian Food Inspection Agency coliform limit for raw meat (103 cfu/g)
‡European Union limit for minced meat for human consumption
R. H. Davies et al.
6 © 2019 Crown Copyright. Journal of Small Animal Practice published by John Wiley & Sons Ltd on behalf of British Small Animal Veterinary Association.
licking) and contact with Salmonella shed in pets’ faeces. Hazard
labelling on commercial raw foods may be poor, as discussed pre-
viously. Trials of domestic cleaning and disinfection routines have
shown them to be ineffective at eliminating Salmonella contami-
nation from bowls (Weese & Rousseau 2006), while Salmonella
contamination of surfaces was prevalent in a raw-feeding kennel
establishment despite good daily cleaning routines (Morley et al.
2006).
The frequency of faecal shedding of Salmonella by dogs fed raw
diets correlates with the Salmonella risk of the food material in
many studies (Joffe & Schlesinger 2002, Finley et al. 2007, Lefe-
bvre et al. 2008, Lenz et al. 2009, Kantere et al. 2016). Indeed,
studies in dogs have identified raw feeding as a major risk factor
for Salmonella shedding (Leonard et al. 2011, Reimschuessel et
al. 2017). The shedding of Salmonella by raw-fed dogs appears
to occur at a similar or higher frequency than the ingestion of
identifiably contaminated pet food (Lenz et al. 2009, Leonard et
al. 2011), suggesting that Salmonella ingestion commonly leads
to chronic or amplified shedding in dogs. This notion is sup-
ported by longitudinal monitoring demonstrating shedding for 1
to 11 days after 1 day of feeding Salmonella-contaminated com-
mercial raw food (Finley et al. 2007). Diarrhoea does not appear
to be a typical feature of Salmonella-shedding dogs (Brisdon et
al. 2006, Finley et al. 2007, Reimschuessel et al. 2017), although
clinical salmonellosis has been reported in association with raw
feeding (Morley et al. 2006).
Salmonella serovars shed by raw-fed dogs correlate with
those isolated from their pet food (Mayer et al. 1976, Joffe &
Schlesinger 2002, Morley et al. 2006, Finley et al. 2007), and
these food isolates, as already discussed, include serovars associ-
ated with human disease. Furthermore, such human-associated
serovars have commonly been isolated from the faeces of dogs
(Reimschuessel et al. 2017), including raw-fed dogs (Lefebvre et
al. 2008, Lenz et al. 2009, Leonard et al. 2011).
Pet-owning households commonly include humans with a
higher risk of contracting Salmonella infection from pets, whether
by virtue of poor hygiene observance around animals (i.e. young
children) or other factors such as advanced age and immuno-
compromise (Stull et al. 2013). However, human clinical disease
associated with exposure to raw-fed pets and their food is likely
to occur as sporadic and isolated cases rather than in outbreaks.
Therefore, such cases typically will not feature prominently, or at
all, in public health reports (Finley et al. 2006, American Veteri-
nary Medical Association 2012), unless in the context of a wider
outbreak (CDC 2018a).
Outbreak investigations have been conducted for human sal-
monellosis cases relating to a contaminated dry dog food manu-
facturing plant (Behravesh et al. 2010) and to the use of frozen
“feeder rodents” for pet reptiles (Cartwright et al. 2016, Kanaga-
rajah et al. 2018). These provide firm supportive evidence for
the zoonotic risk of feeding Salmonella-contaminated products
to pets, and in the investigation by Behravesh et al. (2010), the
risk to young children appeared to be disproportionately high. In
view of the perceived risk of human infection, some public health
bodies have published advice on the safe handling of raw pet food
to mitigate such risks in the home (FDA 2018, CDC 2018b).
E. coli
E. coli typically lives as a commensal enteric species, and strains
may transfer between pet dogs and their owners (Naziri et al.
2016). Pet food diets often contain viable E. coli, reflecting their
universal presence in large numbers within the intestinal tracts
of source animal species and the ease with which faeces may
contaminate many plant ingredients via, for example, wildlife
and water. Higher prevalence values of E. coli-positive samples
have been found among commercial raw pet foods when com-
pared with conventionally processed foods (Strohmeyer et al.
2006, Freeman et al. 2013). Numbers of E. coli in frozen raw pet
food commonly exceed EU limits for minced meat destined for
human consumption, sometimes by two or more orders of mag-
nitude, and also exceed the EU absolute threshold (5×103 cfu/g;
Commission Regulation (EU) No 142/2011) for raw pet food
at the point of production (Nilsson 2015, van Bree et al. 2018).
Some subtypes of E. coli are pathogenic, elaborating certain
colonisation factors and toxins. The shiga toxin-producing E. coli
(STEC; often of serovar O157:H7) are a prominent contempo-
rary example in the human field. STEC O157:H7 was isolated
from some raw diets, around 20% of samples, in a recent survey
from the Netherlands (van Bree et al. 2018). However, serogroup
O157 was not isolated from a total of 616 raw food samples in
two studies in the USA (Lenz et al. 2009, Nemser et al. 2014).
Such differences may reflect variation in local meat contamina-
tion, types of source meat and investigators’ methodology. A
recent investigation in the UK identified closely related STEC
O157 isolates from four human clinical cases, including three
children under 10 years old, and with one fatality (Byrne et al.
2018). In three of these cases, a link with dogs on a raw diet was
established.
Campylobacter species
Campylobacter were not isolated from approximately 300 samples
taken from raw food products in various recent studies in the USA
and Canada (Weese et al. 2005, Strohmeyer et al. 2006, Lenz et
al. 2009). Chicken ingredients might be considered likely sources
of Campylobacter given the well-documented high prevalence of
carcass contamination (Suzuki & Yamamoto 2009, Gonçalves-
Tenório et al. 2018). However, the sensitivity of the organism to
drying, freezing and oxygen, plus relatively insensitive bacterio-
logical detection methods, means that its apparent absence from
prepared foods is perhaps not surprising. In contrast, Bojanic et
al. (2017) isolated Campylobacter jejuni from 22% of raw retail
pet foods in New Zealand. In the same study, univariable analysis
showed an association between Campylobacter upsaliensis-positive
rectal swabs and wet (but not specifically raw) feeding among
both dogs and cats.
It is likely that a small proportion of human campylobac-
teriosis cases are acquired through contact with pets. Evidence
for this includes risk factor analyses (Damborg et al. 2016), the
tendency for asymptomatic and intermittent or extended shed-
ding of human-pathogenic Campylobacter bacteria by young dogs
(Hald et al. 2004, Parsons et al. 2011) and several case studies
Raw feeding dogs and cats
© 2019 Crown Copyright. Journal of Small Animal Practice published by John Wiley & Sons Ltd on behalf of British Small Animal Veterinary Association. 7
where zoonotic transmission has been inferred (Damborg et al.
2016). In one such case, raw feeding of puppies with chicken by-
products was documented (Campagnolo et al. 2018).
Listeria monocytogenes
This organism causes serious disease in many species, including
humans, but rarely among dogs (Pritchard et al. 2016). Listeria
monocytogenes was isolated from 54% of Dutch products sold as
frozen raw pet food (van Bree et al. 2018) and from 16% of raw
(usually frozen) dog and cat foods in the USA (Nemser et al.
2014). None of the 480 conventionally processed dry and semi-
moist pet foods in the latter study yielded the organism.
Yersinia enterocolitica
This is a well-recognised cause of human enteritis, with occa-
sional serious sequelae, in Europe and elsewhere (EFSA & ECDC
2017). The organism survives freeze-thawing (Toora et al. 1992)
and is common in raw pork, pig offal and game meats (Bucher
et al. 2008). Dogs and cats shed human-pathogenic bioserotypes
(Bucher et al. 2008), and PFGE subtyping has implicated con-
taminated pork products as an original source for such shedding
(Fredriksson-Ahomaa et al. 2001). Therefore, improper handling
of contaminated meat (including pig offal) is thought to be a major
risk for human yersiniosis, whilst a minor proportion of cases may
derive from contact with pets (Fredriksson-Ahomaa et al. 2006).
Brucella species
Species of the genus Brucella, while linked to their principal hosts,
do not appear to be strongly host-restricted. Indeed, several,
including Brucella abortus, Brucella melitensis, Brucella canis and
Brucella suis, are zoonotic (Woldemeskel 2013). B. suis is prin-
cipally identified as a cause of brucellosis in feral pigs, but where
dogs commonly encounter or hunt wild pigs or consume pig meat
(such as in parts of Australia), clinical orthopaedic and reproduc-
tive disease in dogs associated with the organism is recognised (Mor
et al. 2016). B. suis has a low infectious dose for humans, and zoo-
notic disease is often acquired through butchering or consuming
wildlife (Woldemeskel 2013), although transmission to humans
from dogs via secretions and urine is considered to be possible
under favourable circumstances (Neiland & Miller 1981). B. suis
was recently found in frozen hare meat imported from Argentina
into the Netherlands and the UK for raw pet diets, being identi-
fied following clinical disease in an exposed dog (Frost 2017).
Miscellaneous
Various other potentially pathogenic bacterial entities have been
either identified in raw pet diets (Staphylococcus aureus, Clos-
tridium species) or considered potential disease risks from source
livestock (Bacillus cereus, Bacillus anthracis, Burkholderia spe-
cies), especially if food is left at ambient temperature before con-
sumption (LeJeune & Hancock 2001, Weese et al. 2005, Burns
2012). However, the magnitude of risk posed by these organisms
is currently unknown. O’Halloran et al. (2018) have suggested
the possibility of indoor domestic cats being infected by Myco-
bacterium bovis via raw feeding, although evidence of infection
and of transmission route(s) in the cited cases remains uncertain
(Middlemiss & Clark 2018).
Antimicrobial resistance
The risk that raw feeding might enhance the spread of
antimicrobial- resistant bacteria has been considered by several
investigations. Heat treatment is a critical control step in the
elimination or marked reduction of bacteria arising from live-
stock sources, which is not available to producers of raw food.
Both pathogenic and commensal bacterial species from livestock
may carry antimicrobial- resistance genes, some of which can be
readily transmissible.
Extended-spectrum beta-lactamase (ESBL) resistance is typi-
cally borne on transmissible plasmids and is currently common
among E. coli, and other Enterobacteriaceae, in poultry produc-
tion in Europe and elsewhere (Scientific Advisory Group on
Antimicrobials of the Committee for Medicinal Products for Vet-
erinary Use 2009). ESBL and the related AmpC-type resistance
confer reduced susceptibility to extended-spectrum cephalospo-
rins, these being considered of critical importance in human
medicine (WHO 2016). A study in the Netherlands reported
that 28 of 35 raw pet food products yielded ESBL-positive E.
coli (van Bree et al. 2018), while in Italy, ESBL producers were
prevalent among Salmonella isolates from date-expired human
products available for pet food use (Bacci et al. 2019). A second
Dutch study also found that a similar proportion of raw prod-
ucts (14 of 18) yielded ESBL- or AmpC-positive Enterobacteria-
ceae compared with none of 35 processed products (Baede et al.
2017), whilst 23% of Nordic raw food samples containing poul-
try meat yielded plasmid-borne AmpC genes (Nilsson 2015).
This apparently elevated risk of extended-spectrum cephalo-
sporin resistance compared with heat-treated food, coupled with
the previously discussed evidence for relatively high counts of
E. coli and related organisms in raw food, appears to translate
into an increased risk of the presence, or of heavy shedding, of
resistant organisms. There was a strong association between raw
feeding and the likelihood of faecal shedding of E. coli exhibiting
AmpC-type resistance among therapy dogs in Canada over the
course of 18 months (Lefebvre et al. 2008). Two Dutch longitu-
dinal studies reported associations between raw feeding and fae-
cal E. coli from dogs showing ESBL resistance (Baede et al. 2015)
or faecal Enterobacteriaceae from cats showing ESBL/AmpC
resistance (Baede et al. 2017). This last study also found that,
where phenotypically resistant Enterobacteriaceae were isolated,
the mean count (colony-forming units per gram faeces) for such
isolates among raw-fed cats was over two orders of magnitude
higher than among controls.
In two cross-sectional studies of dogs in the UK, associations
with raw feeding were found for AmpC phenotype E. coli (Schmidt
et al. 2015) and for third-generation cephalosporin- resistant E. coli
(Groat et al. 2016). Another UK cross-sectional study reported a
strong association between feeding raw poultry and faecal ESBL E.
coli among veterinary-visiting dogs (Wedley et al. 2017).
R. H. Davies et al.
8 © 2019 Crown Copyright. Journal of Small Animal Practice published by John Wiley & Sons Ltd on behalf of British Small Animal Veterinary Association.
In addition to ESBL/AmpC resistance studies, raw feeding has
also been identified as a risk factor for faecal shedding by dogs of
E. coli exhibiting other antimicrobial drug resistances (Leonard
et al. 2015, Groat et al. 2016). This is similar for resistant Sal-
monella (Leonard et al. 2015) or for multi-drug-resistant E. coli
(Groat et al. 2016, Wedley et al. 2017). Greyhounds fed on raw
meat were also found to commonly shed multi-resistant strains
of Salmonella (Morley et al. 2006), and multi-resistant S. Read-
ing has been isolated from raw pet food and from two infected
in- contact children (MDH 2018, CDC 2018a).
Multi-resistant E. coli and Salmonella strains were prevalent
among poultry and pork material available for pet food manufac-
ture in Italy (Bacci et al. 2019), and there is a particular concern
in the UK about the use of imported poultry meat for RMBDs.
The consumption by dogs and cats of multi-resistant epidemic
Salmonella serovars (such as S. Kentucky, S. Infantis, S. Stanley,
S. Heidelberg and ciprofloxacin-resistant S. Enteritidis) that are
not currently present in UK food animals (EFSA 2012, Springer
et al. 2014, Shah et al. 2017) pose a risk of the subsequent incur-
sion of such resistant strains into British poultry flocks via pets
shedding the organisms. Free-range flocks with public footpaths
across range areas and poultry farms with resident dogs are par-
ticularly at risk.
Non-bacterial pathogens and zoonoses
Several helminths and protozoa have been proposed as potential
pathogenic risks for raw-fed cats and dogs and/or for in-contact
owners and livestock. These include: Neosporum caninum, Sarco-
cystis species, Toxoplasma gondii, Isospora species, Cryptosporidium
parvum, Giardia, Echinococcus granulosus, Echinococcus multi-
locularis, Taenia hydatigena, Taenia ovis and Trichinella species
(LeJeune & Hancock 2001, Macpherson 2005, Silva & Mach-
ado 2016, van Bree et al. 2018). There are well-characterised
risks to humans or livestock from pets shedding some of these
strains, but useful data on the risks posed by raw pet food with
respect to these organisms is sparse. The commonly practiced
freeze- thawing of raw diets will have a pronounced detrimental
effect on protozoa and helminths in contrast with many bacteria,
although effects vary by organism and by the temperature and
duration of freezing (PFMA 2017).
For T. gondii, there is an established zoonotic risk from
infected cats. Moreover, raw-fed cats have been shown to demon-
strate increased toxoplasma seroprevalence and oocyst shedding
(Lopes et al. 2008, Coelho et al. 2011, Freeman et al. 2013), but
there is also a potential direct infection route to humans from
raw meat (Macpherson 2005). PCR techniques detected Sarco-
cystis and Toxoplasma in a minority of Dutch raw food samples
(van Bree et al. 2018). Similarly, DNA of Cryptosporidium (but
not Toxoplasma or Neosporum) was found in a small minority of
raw and canned foods in the USA (Strohmeyer et al. 2006). In
none of these cases was the viability of the protozoa established.
There are few previously published comments concerning
potential issues with viral pathogens in raw pet foods. Cases of
pseudorabies virus infection have been reported in cats and dogs
after ingesting meat from affected pig herds (Hoorens 1978, Kot-
nik et al. 2006) and, similarly, dogs appear susceptible to Afri-
can Horse Sickness after ingesting meat from clinically affected
horses (O’Dell et al. 2018). Rabies and hepatitis E are viruses that
may infect the tissues of source animals for raw food, and there
are data suggesting a risk to pets and/or their owners following
ingestion (Bell & Moore 1971, Meng 2005). However, such risks
are as yet unproven. Virus contamination introduced at process-
ing plants might also pose a risk to pet owners. The human noro-
virus has potential for such a role as it is common, is shed heavily
by infected individuals during acute illness and, moreover, it sur-
vives passage through the canine gastrointestinal tract (Summa
et al. 2012). While the risks of virus contamination may not be
unique to raw diets, the potential of conventional processing to
effect elimination or marked reduction in viability has been dem-
onstrated, at least for a veterinary calicivirus (Haines et al. 2015).
SUMMARY
The use of raw diets is a growing phenomenon among pet owners
in developed countries, who in previous decades had embraced
the nutritional expertise and convenience offered by processed
pet food industries. There is a polarisation in the public debate
on the merits of raw feeding, touching as it does on emotionally
charged issues such as the care and welfare of pets and a counter-
cultural response to perceived vested interests in the animal feed
and other pet care industries. Anecdote, endorsement and firmly
expressed opinion have been used on both sides of the debate,
and the “campaigning” tone has been aided by large gaps in data.
Given the typical differences between the balance of nutrient
groups in raw and processed foods, it is perhaps not surprising
that formal investigations have pointed to differences in the gut
microbiome between raw- and conventionally fed animals, nor
that, anecdotally, owners report differences in stool quality. For-
mal data on a limited number of apparently healthy individuals
does not suggest an association between raw feeding and a reduc-
tion in periodic episodes of diarrhoea. Nonetheless, it is plausible
that, for certain individuals and certain diets, raw feeding may
lead to improvements in clinical signs relating to, for example,
food intolerances, inflammatory bowel conditions and some
other conditions in which dietary influences have been estab-
lished. What appears less plausible, from a scientific standpoint,
are the very broad benefits claimed for raw feeding (without for-
mal evidence) with respect to an extensive range of inflammatory,
infectious, neoplastic, endocrine, behavioural and other condi-
tions. Such claims cannot be made directly by manufacturers and
retailers in territories where there are stringent evidence rules for
commercial advertising. Nonetheless, anecdotes and personal
endorsements implying such benefits are promoted in company
communications (Natures:menu 2017, BARF World 2018).
With respect to the potential adverse effects of raw feeding,
evidence of risk is mostly piecemeal in nature and commonly fails
to demonstrate tangible consequences of the identified hazard.
Thus, warnings of risks remain susceptible to being dismissed as
“scare stories” by proponents of raw feeding. However, there is a
growing body of formal investigations and peer-reviewed publi-
cations documenting various aspects of risk and adverse effects
Raw feeding dogs and cats
© 2019 Crown Copyright. Journal of Small Animal Practice published by John Wiley & Sons Ltd on behalf of British Small Animal Veterinary Association. 9
associated with raw feeding, although outcomes are still largely
documented as case reports or in the context of small studies.
There appears little doubt from survey evidence that the preva-
lence of potentially serious pathogens is substantially higher in
raw pet food than in heat-treated food. Most evidence in this
respect has accrued for Salmonella risk. Whilst targeted and sys-
tematic monitoring of households may yet be needed to quantify
the human health hazards of raw feeding, human salmonellosis
outbreak investigations in related situations (contaminated pet
treats and dry food, rodent carcasses for feeding reptiles) have
clearly demonstrated the risk.
On a precautionary basis, the advice against raw feeding issued
by various professional bodies appears justified, especially in the
case of the many households that include individuals especially
vulnerable to infectious disease. In addition, aspects of raw feed-
ing that may have been underappreciated until recently include
the increased frequency and number of antimicrobial drug-
resistant bacteria in raw foods and the risk of exotic pet, livestock
and zoonotic diseases associated with imported raw meats.
In conclusion, there is much in the current movement for raw
feeding of pets that follows a pattern of counter-establishment
beliefs (appealing variously to ideas of simplicity, intuition and
contrarian enlightenment), which are also recognised in many
other fields. Such beliefs often use the language and style of for-
mal science while using emotive rationales and relying on anec-
dote and highly selective data and interpretations as an evidence
base. The subsequent development of business and marketing
strategies for raw feeding may reinforce a public perception of
the reliability of claims made.
Currently, data for the nutritional, medical and public health
risks of raw feeding are fragmentary, but they are increasingly
forming a compelling body of formal scientific evidence. It
appears important that veterinary and public health practitioners
and organisations continue to exercise a responsibility to com-
municate this to both consumers and producers of raw pet food.
Given that raw feeding is currently well-established, it may be
that mitigation measures focussed on human health, by empha-
sising safer handling of products in the home, will have the most
significant impact in the short- to medium term.
Acknowledgements
This review was funded by Defra/Welsh Government/Scot-
tish Government-funded APHA surveillance programmes. The
author(s) are grateful to Scott Reaney (APHA) and Mark Bond
(Food Standards Agency) for helpful comments on the manuscript.
Conflict of interest
No conflicts of interest have been declared.
References
American Veterinary Medical Association. (2012) Raw pet foods and the AVMA’s
Policy: FAQ. AVMA. https://www.avma.org/KB/Resources/FAQs/Pages/Raw-
Pet- Foods- and- the- AVMA- Policy- FAQ.aspx. Accessed November 3, 2017
APHA (2016) Salmonella in Livestock Production in GB, 2015. Animal and Plant
Health Agency, Addlestone, UK https://www.gov.uk/government/publications/
salmonella- in- livestock- production- in- great- britain- 2015
APHA (2017) Salmonella in Livestock Production in GB, 2016. Animal and Plant
Health Agency, Addlestone, UK https://www.gov.uk/government/publications/
salmonella- in- livestock- production- in- great- britain- 2016
APPA. (2018) The 2017-2018 APPA National Pet Owners Survey Debut. American
Pet Products Association. http://americanpetproducts.org/Uploads/MemSer-
vices/GPE2017_NPOS_Seminar.pdf. Accessed December 4, 2018
AZA Canid TAG (2012) Large Canid (Canidae) Care Manual. Association of Zoos
and Aquariums, Silver Spring, Maryland, USA
Azza, H. E. B., Sahar, M. A. E., Hala, S. M., et al. (2014) Evaluation of bacterial
hazards in various pet foods. Global Journal of Agriculture and Food Safety Sci-
ences 1, 432-439
Bacci, C., Vismarra, A., Dander, S., et al. (2019) Occurrence and antimicrobial
profile of bacterial pathogens in former foodstuff meat products used for pet
diets. Journal of Food Protection 82, 316-324
Baede, V. O., Wagenaar, J. A., Broens, E. M., et al. (2015) Longitudinal study of
extended-spectrum-β-lactamase- and AmpC-producing Enterobacteriaceae in
household dogs. Antimicrobial Agents and Chemotherapy 59, 3117-3124
Baede, V. O., Broens, E. M., Spaninks, M. P., et al. (2017) Raw pet food as a risk
factor for shedding of extended-spectrum beta-lactamase-producing Enterobac-
teriaceae in household cats. PLoS One 12, e0187239
BARF World. (2018) BARF World. http://barfworld.com/index.php. Accessed
November 14, 2017
Behravesh, C. B., Ferraro, A., Deasy, M., et al. (2010) Human Salmonella infec-
tions linked to contaminated dry dog and cat food, 2006-2008. Pediatrics 126,
477-483
Bell, J. F. & Moore, G. J. (1971) Susceptibility of carnivora to rabies virus adminis-
tered orally. American Journal of Epidemiology 93, 176-182
Billinghurst, I. (1993) Give Your Dog a Bone: The Practical Commonsense Way to
Feed Dogs for a Long Healthy Life. Warrigal Publishing Lithgow, Australia
Bojanic, K., Midwinter, A. C., Marshall, J. C., et al. (2017) Isolation of Campylo-
bacter spp. from client-owned dogs and cats, and retail raw meat pet food in the
Manawatu, New Zealand. Zoonoses and Public Health 64, 438-449
van Bree, F. P. J., Bokken, G. C. A. M., Mineur, R., et al. (2018) Zoonotic bacteria
and parasites found in raw meat-based diets for cats and dogs. Veterinary
Record 182, 50-50
Brisdon, S., Galanis, E., Colindres, R., et al. (2006) An international outbreak of
human salmonellosis associated with animal-derived pet treats - Canada and
Washington state, 2005. Canada Communicable Disease Report 32, 150-155
Bucher, M., Meyer, C., Grötzbach, B., et al. (2008) Epidemiological data on patho-
genic Yersinia enterocolitica in southern Germany during 2000-2006. Food-
borne Pathogens and Disease 5, 273-280
Burns, K. M. (2012) Alternative and raw food diets: what do we know? Proceed-
ings of the North American Veterinary Conference, volume 26. Veterinary Tech-
nician Proceedings. Orlando, FL, USA, 14-18 January 2012. The North American
Veterinary Conference.
Byrne, L., Aird, H., Jorgensen, F., et al. (2018) Investigation into an outbreak of
Shiga toxin producing Escherichia coli, August 2017 (No. 2018489). Pub-
lic Health England. https://assets.publishing.service.gov.uk/government/
uploads/system/uploads/attachment_data/file/748774/STEC_O157_
PT21.28_Outbreak_Report.pdf. Accessed December 4, 2018
Campagnolo, E. R., Philipp, L. M., Long, J. M., et al. (2018) Pet-associated Cam-
pylobacteriosis: a persisting public health concern. Zoonoses and Public Health
65, 304-311
Canada, H. (2000) Human health risk from exposure to natural dog treats. Canada
Communicable Disease Report 26, 41-42
Cartwright, E. J., Nguyen, T., Melluso, C., et al. (2016) A multistate investigation of
antibiotic-resistant Salmonella enterica serotype I 4,[5],12:i:- infections as part
of an international outbreak associated with frozen feeder rodents. Zoonoses
and Public Health 63, 62-71
CDC. (2018a) Outbreak of multidrug-resistant Salmonella infections linked to raw
turkey product. Centers for Disease Control and Prevention https://www.cdc.
gov/salmonella/reading- 07- 18/index.html. Accessed July 23, 2018
CDC. (2018b) Pet food safety. Centers for Disease Control and Prevention. https://
www.cdc.gov/features/pet-food-safety/index.html. Accessed July 18, 2018
Center for Veterinary Medicine. (2004) Guidance for industry #122: manufacture
and labeling of raw meat foods for companion and captive noncompanion car-
nivores and omnivores. U.S. Department of Health and Human Services, Food
and Drug Administration. https://www.fda.gov/downloads/AnimalVeterinary/
GuidanceComplianceEnforcement/GuidanceforIndustry/UCM052662.pdf.
Accessed July 17, 2018
Center for Veterinary Medicine. (2016) Guidance for industry #241: small entity
compliance guide. U.S. Department of Health and Human Services, Food and
Drug Administration. https://www.fda.gov/downloads/animalveterinary/guid-
ancecomplianceenforcement/guidanceforindustry/ucm499202.pdf. Accessed
July 17, 2018
Chengappa, M. M., Staats, J., Oberst, R. D., et al. (1993) Prevalence of Salmonella
in raw meat used in diets of racing greyhounds. Journal of Veterinary Diagnostic
Investigation 5, 372-377
Clark, C., Cunningham, J., Ahmed, R., et al. (2001) Characterization of Salmonella
associated with pig ear dog treats in Canada. Journal of Clinical Microbiology
39, 3962-3968
Cobb, M. A. & Stavisky, J. (2013) Salmonella infections in dogs and cats. In: Sal-
monella in Domestic Animals. 2nd edn. Eds P. A. Barrow and U. Methner. CAB
International, Wallingford, U.K. pp 318-336
Coelho, W. M. D., do Amarante, A. F. T., Apolinário, J. C., et al. (2011) Seroepidemi-
ology of Toxoplasma gondii, Neospora caninum, and Leishmania spp. infections
and risk factors for cats from Brazil. Parasitology Research 109, 1009-1013
R. H. Davies et al.
10 © 2019 Crown Copyright. Journal of Small Animal Practice published by John Wiley & Sons Ltd on behalf of British Small Animal Veterinary Association.
Damborg, P., Broens, E. M., Chomel, B. B., et al. (2016) Bacterial zoonoses trans-
mitted by household pets: state-of-the-art and future perspectives for targeted
research and policy actions. Journal of Comparative Pathology 155, S27-S40
Domingues, A. R., Pires, S. M., Halasa, T., et al. (2012) Source attribution of
human salmonellosis using a meta-analysis of case-control studies of sporadic
infections. Epidemiology and Infection 140, 959-969
EFSA (2012) Scientific opinion on an estimation of the public health impact of
setting a new target for the reduction of Salmonella in turkeys. EFSA Journal
10, 2616 (89 pp.)
EFSA & ECDC (2017) The European Union summary report on trends and sources
of zoonoses, zoonotic agents and food-borne outbreaks in 2016. EFSA Journal
15, 5077 (228 pp.)
European Commission (2018) Guidelines for the feed use of food no longer
intended for human consumption. Official Journal of the European Union C 133,
2-18
Fascetti, A. J. (2015) Are raw food diets radical or reasonable? A review of the
evidence. Proceedings of the NAVC Conference. Volume 29, Orlando, FL, USA,
January 17-21, 2015, Small Animal and Exotics Edition, Book 1 and Book 2.
North American Veterinary Community (NAVC), pp578-581
FDA. (2018) Avoid the dangers of raw pet food. U.S. Food and Drug Administra-
tion. https://www.fda.gov/AnimalVeterinar y/ResourcesforYou/AnimalHealth-
Literacy/ucm368730.htm. Accessed July 18, 2018
Finley, R., Reid-Smith, R. & Weese, J. S. (2006) Human health implications of
Salmonella-contaminated natural pet treats and raw pet food. Clinical Infectious
Diseases 42, 686-691
Finley, R., Ribble, C., Aramini, J., et al. (2007) The risk of salmonellae shedding by
dogs fed Salmonella-contaminated commercial raw food diets. Canadian Veteri-
nary Journal 48, 69-75
Finley, R., Reid-Smith, R., Ribble, C., et al. (2008) The occurrence and antimicrobial
susceptibility of salmonellae isolated from commercially available canine raw
food diets in three Canadian cities. Zoonoses and Public Health 55, 462-469
Fredriksson-Ahomaa, M., Korte, T. & Korkeala, H. (2001) Transmission of Yersinia
enterocolitica 4/O:3 to pets via contaminated pork. Letters in Applied Microbiol-
ogy 32, 375-378
Fredriksson-Ahomaa, M., Stolle, A. & Korkeala, H. (2006) Molecular epidemiolog y
of Yersinia enterocolitica infections. FEMS Immunology and Medical Microbiology
47, 315-329
Freeman, L. M. & Michel, K. E. (2001) Evaluation of raw food diets for dogs. Jour-
nal of the American Veterinar y Medical Association 218, 705-709
Freeman, L. M., Chandler, M. L., Hamper, B. A., et al. (2013) Current knowledge
about the risks and benefits of raw meat based diets for dogs and cats. Journal
of the American Veterinary Medical Association 243, 1549-1558
Frost, A. (2017) Feeding of raw Brucella suis-infected meat to dogs in the UK.
Veterinary Record 181, 484-484
Glasgow, A. G., Cave, N. J., Marks, S. L., et al. (2002) Role of diet in the health
of the feline intestinal tract and in inflammatory bowel disease. University of
California, Davies. https://www.semanticscholar.org/paper/Role- of- Diet- in- the- -
Health- of- the- Feline- Intestinal- Glasgow- Cave/af2f916e5892a344347291b-
c403aa883c10b5638. Accessed December 4, 2018
Gonçalves-Tenório, A., Silva, B. N., Rodrigues, V., et al. (2018) Prevalence of patho-
gens in poultry meat: a meta-analysis of European published surveys. Food 7,
69
Groat, E.F., Williams, N.J., Pinchbeck, G., et al. (2016) Canine raw meat diets
and antimicrobial resistant E. coli: is there a link? Proceedings of the BSAVA
Congress 2016. Birmingham, UK, April 7-10. British Small Animal Veterinar y
Association, p540
Haines, J., Patel, M., Knight, A. I., et al. (2015) Thermal inactivation of feline
calicivirus in pet food processing. Food and Environmental Virology 7, 374-380
Hald, B., Pedersen, K., Wainø, M., et al. (2004) Longitudinal study of the excretion
patterns of thermophilic Campylobacter spp. in young pet dogs in Denmark.
Journal of Clinical Microbiology 42, 2003-2012
Hamper, B. A., Bartges, J. W. & Kirk, C. A. (2017) Evaluation of two raw diets vs a
commercial cooked diet on feline growth. Journal of Feline Medicine and Surgery
19, 424-434
Hoorens, J. (1978) Rauw vlees als besmettngsbron voor de ziekte van Aujeszky bij
katachtigen [uncooked meat as source of infection with Aujeszky’s disease in
felines]. Vlaams Diergeneeskundig Tijdschrift 47, 309-312
Joffe, D. J. & Schlesinger, D. P. (2002) Preliminary assessment of the risk of Sal-
monella infection in dogs fed raw chicken diets. Canadian Veterinary Journal
43, 441-442
Kanagarajah, S., Waldram, A., Dolan, G., et al. (2018) Whole genome sequencing
reveals an outbreak of Salmonella Enteritidis associated with reptile feeder
mice in the United Kingdom, 2012-2015. Food Microbiology 71, 32-38
Kantere, M. C., Athanasiou, L. V., Evangelopoulou, G., et al. (2016) Detection
of uncommon zoonotic antimicrobial-resistant Salmonella serovars in dogs.
Proceedings of the International Society for Companion Animal Infectious Dis-
eases (ISCAID) 4th Biennial Symposium. Bristol, UK, October 16-19. pIP-6
Kim, J., An, J.-U., Kim, W., et al. (2017) Differences in the gut microbiota of dogs
(Canis lupus familiaris) fed a natural diet or a commercial feed revealed by the
Illumina MiSeq platform. Gut Pathogens 9, 68
Kölle, P. & Schmidt, M. (2015) BARF (Biologisch Artgerechte Rohfütterung) als
Ernährungsform bei Hunden [Raw-meat-based diets (RMBD) as a feeding prin-
ciple for dogs]. Tierarztliche Praxis 43, 409-419
Kotnik, T., Suhadolc, S., Juntes, P., et al. (2006) Case report of a pseudorabies
(Aujeszky’s disease) in a bitch. Slovenian Veterinary Research 43, 143-145
Lefebvre, S. L., Reid-Smith, R., Boerlin, P., et al. (2008) Evaluation of the risks of
shedding salmonellae and other potential pathogens by therapy dogs fed raw
diets in Ontario and Alberta. Zoonoses and Public Health 55, 470-480
LeJeune, J. T. & Hancock, D. D. (2001) Public health concerns associated with
feeding raw meat diets to dogs. Journal of the American Veterinary Medical Asso-
ciation 219, 1222-1225
Lenox, C., Becvarova, I. & Archipow, W. (2015) Metabolic bone disease and central
retinal degeneration in a kitten due to nutritional inadequacy of an all-meat raw
diet. Journal of Feline Medicine and Surgery Open Reports 1, 1-5
Lenz, J., Joffe, D., Kauffman, M., et al. (2009) Perceptions, practices, and conse-
quences associated with foodborne pathogens and the feeding of raw meat to
dogs. Canadian Veterinary Journal 50, 637-643
Leonard, E. K., Pearl, D. L., F inley, R. L., et al. (2011) Evaluation of pet-related
management factors and the risk of Salmonella spp. carriage in pet dogs from
volunteer households in Ontario (2005-2006). Zoonoses and Public Health 58,
140-149
Leonard, E. K., Pearl, D. L., Janecko, N., et al. (2015) Risk factors for carriage of
antimicrobial-resistant Salmonella spp and Escherichia coli in pet dogs from
volunteer households in Ontario, Canada, in 2005 and 2006. American Journal
of Veterinary Research 76, 959-968
Lopes, A. P., Cardoso, L. & Rodrigues, M. (2008) Serological survey of Toxoplasma
gondii infection in domestic cats from northeastern Portugal. Veterinary Parasi-
tology 155, 184-189
Macpherson, C. N. L. (2005) Human behaviour and the epidemiology of parasitic
zoonoses. International Journal for Parasitology 35, 1319-1331
Mayer, H., Kolb, A. & Gehring, H. (1976) Epidemiologische Untersuchungn bei
einer Salmonellenenzootie bei diensthunden der Polizei [Epidemiological sur-
vey on endemic salmonellosis in police dogs]. Praktische Tierarzt 57, 289-295
MDH. (2018) News release: Salmonella cases linked to raw meat dog food. Min-
nesota Department of Health. http://www.health.state.mn.us/news/press-
rel/2018/salmonella020918.html. Accessed July 23, 2018
Mehlenbacher, S., Churchill, J., Olsen, K. E., et al. (2012) Availability, brands, label-
ling and Salmonella contamination of raw pet food in the Minneapolis/St. Paul
area. Zoonoses and Public Health 59, 513-520
Meng, X. J. (2005) Hepatitis E virus: cross-species infection and zoonotic risk.
Clinical Microbiology Newsletter 27, 43-48
Middlemiss, C. & Clark, J. (2018) Mycobacterium in pets. Veterinary Record 183, 571
Mor, S. M., Wiethoelter, A. K., Lee, A., et al. (2016) Emergence of Brucella suis
in dogs in New South Wales, Australia: clinical findings and implications for
zoonotic transmission. BMC Veterinary Research 12, 199
Morgan, S. K., Willis, S. & Shepherd, M. L. (2017) Survey of owner motivations
and veterinary input of owners feeding diets containing raw animal products.
PeerJ 5, e3031
Morley, P. S., Strohmeyer, R. A., Tankson, J. D., et al. (2006) Evaluation of the
association between feeding raw meat and Salmonella enterica infections at a
greyhound breeding facility. Journal of the American Veterinary Medical Associa-
tion 228, 1524-1532
Natures:menu. (2017) Raw dog food & natural cat food. Natures Menu. https://
www.naturesmenu.co.uk/. Accessed April 23, 2018.
Naziri, Z., Derakhshandeh, A., Firouzi, R., et al. (2016) DNA fingerprinting
approaches to trace Escherichia coli sharing between dogs and owners. Journal
of Applied Microbiology 120, 460-468
Neiland, K. A. & Miller, L. G. (1981) Experimental Brucella suis type 4 infections in
domestic and wild Alaskan carnivores. Journal of Wildlife Diseases 17, 183-189
Nemser, S. M., Doran, T., Grabenstein, M., et al. (2014) Investigation of Liste-
ria, Salmonella, and toxigenic Escherichia coli in various pet foods. Foodborne
Pathogens and Disease 11, 706-709
Nilsson, O. (2015) Hygiene quality and presence of ESBL-producing Escherichia
coli in raw food diets for dogs. Infection Ecology & Epidemiology 5, 28758
O’Dell, N., Arnot, L., Janisch, C. E., et al. (2018) Clinical presentation and pathol-
ogy of suspected vector transmitted African horse sickness in south African
domestic dogs from 2006 to 2017. Veterinary Record 182, 715-715
O’Halloran, C., Gunn-Moore, D., Reed, N., et al. (2018) Mycobacterium bovis in pet
cats. Veterinary Record 183, 510
Parsons, B. N., Williams, N. J., Pinchbeck, G. L., et al. (2011) Prevalence and shed-
ding patterns of campylobacter spp. in longitudinal studies of kennelled dogs.
The Veterinary Journal 190, 249-254
PFMA. (2017) Guidelines for the manufacture of raw pet food in the UK. Pet Food
Manufacturer’s Association (UK). https://www.pfma.org.uk/uk- pet- food- codes-
of- practice. Accessed November 7, 2017
Pitout, J. D. D., Reisbig, M. D., Mulvey, M., et al. (2003) Association between
handling of pet treats and infection with Salmonella enterica serotype Newport
expressing the AmpC ß-lactamase, CMY-2. Journal of Clinical Microbiology 41,
4578-4582
Pritchard, J. C., Jacob, M. E., Ward, T. J., et al. (2016) Listeria monocytogenes
septicemia in an immunocompromised dog. Veterinary Clinical Pathology 45,
254-259
Reimschuessel, R., Grabenstein, M., Guag, J., et al. (2017) Multilaboratory survey
to evaluate Salmonella prevalence in diarrheic and nondiarrheic dogs and cats
in the United States between 2012 and 2014. Journal of Clinical Microbiology
55, 1350-1368
Raw feeding dogs and cats
© 2019 Crown Copyright. Journal of Small Animal Practice published by John Wiley & Sons Ltd on behalf of British Small Animal Veterinary Association. 11
Sandri, M., dal Monego, S., Conte, G., et al. (2017) Raw meat based diet influ-
ences faecal microbiome and end products of fermentation in healthy dogs.
BMC Veterinary Research 13, 6 5
Schlesinger, D. P. & Joffe, D. J. (2011) Raw food diets in companion animals: A
critical review. Canadian Veterinary Journal 52, 50-54
Schmidt, V. M., Pinchbeck, G. L., Nuttall, T., et al. (2015) Antimicrobial resistance
risk factors and characterisation of faecal E. coli isolated from healthy Labrador
retrievers in the United Kingdom. Preventive Veterinary Medicine 119, 31-40
Schnirring, L. (2018) Turkey-linked Salmonella outbreak total climbs to 164. CIDRAP
News, November 8. http://www.cidrap.umn.edu/news- perspective/2018/11/
turkey- linked- salmonella- outbreak- total- climbs- 164. Accessed November 12, 2018
Scientific Advisory Group on Antimicrobials of the Committee for Medicinal Prod-
ucts for Veterinary Use (2009) Reflection paper on the use of third and fourth
generation cephalosporins in food producing animals in the European Union:
development of resistance and impact on human and animal health. Journal of
Veterinary Pharmacology and Therapeutics 32, 515-533
Shah, D. H., Paul, N. C., Sischo, W. C., et al. (2017) Population dynamics and
antimicrobial resistance of the most prevalent poultry-associated Salmonella
serotypes. Poultry Science 96, 687-702
Silva, R. C. & Machado, G. P. (2016) Canine neosporosis: perspectives on patho-
genesis and management. Veterinary Medicine: Research and Reports 7, 59-70
Springer, B., Allerberger, F. & Kornschober, C. (2014) Letter to the editor: Salmo-
nella Stanley outbreaks – a prompt to reevaluate existing food regulations.
Eurosurveillance 19, 20818
Steenkamp, G. & Gorrel, C. (1999) Oral and dental conditions in adult African
wild dog skulls: a preliminary report. Journal of Veterinary Dentistry 16, 65-68
Strohmeyer, R. A., Morley, P. S., Hyatt, D. R., et al. (2006) Evaluation of bacterial
and protozoal contamination of commercially available raw meat diets for dogs.
Journal of the American Veterinary Medical Association 228, 537-542
Stull, J. W., Peregrine, A. S., Sargeant, J. M., et al. (2013) Pet husbandry and infec-
tion control practices related to zoonotic disease risks in Ontario, Canada. BMC
Public Health 13, 520
Summa, M., von Bonsdorff, C.-H. & Maunula, L. (2012) Pet dogs—A transmission
route for human noroviruses? Journal of Clinical Virology 53, 244-247
Suzuki, H. & Yamamoto, S. (2009) Campylobacter contamination in retail poultry
meats and by-products in the world: a literature survey. Journal of Veterinary
Medical Science 71, 255-261
Toora, S., Buduamoako, E., Ablett, R., et al. (1992) Effect of high-temperature
short-time pasteurization, freezing and thawing and constant freezing, on the
survival of Yersinia enterocolitica in milk. Journal of Food Protection 55, 803-
805
Towell, T.L. (2008) Alternative & raw food diets: what do we know? Proceedings
of the North American Veterinary Conference, Volume 22. Orlando, FL, USA,
pp147-150
Waters, A. (2017) Raw diets: are we at a turning point? Veterinary Record 181,
384-384
Wedley, A. L., Dawson, S., Maddox, T. W., et al. (2017) Carriage of antimicrobial
resistant Escherichia coli in dogs: prevalence, associated risk factors and
molecular characteristics. Veterinary Microbiology 199, 23-30
Weese, J. S. & Rousseau, J. (2006) Sur vival of Salmonella Copenhagen in food
bowls following contamination with experimentally inoculated raw meat: effects
of time, cleaning, and disinfection. The Canadian Veterinary Journal 47, 887- -
889
Weese, J. S., Rousseau, J. & Arroyo, L. (2005) Bacteriological evaluation of com-
mercial canine and feline raw diets. Canadian Veterinary Journal 46, 513-516
WHO. (2016) Critically important antimicrobials for human medicine. 5th revi-
sion. World Health Organization. http://www.who.int/foodsafety/publications/
antimicrobials- fifth/en/ [accessed on 5 April 2019]
Woldemeskel, M. (2013) Zoonosis due to Brucella suis with special reference to
infection in dogs (carnivores): a brief review. Open Journal of Veterinar y Medi-
cine 03, 213-221
World Small Animal Veterinary Association. (2015) WSAVA Global Nutrition Com-
mittee Statement on Risks of Raw Meat-Based Diets. WSAVA. http://www.
wsava.org/About/Postion- statement. Accessed November 2, 2017