A Survey among Dog and Cat Owners on Pet Food Storage and Preservation in the Households

Abstract

Simple Summary
Proper dog and cat food preservation is fundamental to ensure the best quality of the diet right up to the moment of feeding, given that nutritional value, safety and sensory properties can be irreparably damaged by environment and time. To this end, a survey was conducted to explore how pet owners store both commercial and home-prepared diets. On the whole, despite the wide variability of practices adopted, most of the 2221 respondents implemented good storage management. Room temperature was the most overlooked parameter during storage, and this may be a cause of concern because exposure to warmth can enhance rancidity, especially in diet formulations rich in fats and oils. For this reason, veterinarians should provide precise instructions on storing perishable ingredients to those who feed home-prepared diets. Moreover, respondents of older generations appeared to distrust the use of preservatives in commercial pet foods and often deemed their inclusion harmful and unnecessary. Pet food manufacturers should discourage skepticism of the additives crucial to long-term commercial pet food conservation through better communication.

Abstract
Background: Pet food storage plays a crucial role in maintaining the nutritional and sensory properties of purchased products over time. Methods: An online survey was developed to collect data regarding owners’ storage habits for both commercial and home-made diets. Results: The questionnaire was completed by 1545 dog owners and 676 cat owners. Pet and owner age played roles in the choice of the type of diet (commercial vs. home-cooked vs. raw meat-based) adopted. Kibble feeders (75.7%) usually bought one (50.1%) or two (24.6%) packages at a time, and most pets (64.4%) took a minimum four weeks to consume an entire bag. Almost half of the owners (43.5%) used a container to store pet food (plastic bins for 79.5%). Pet food was commonly stored in the kitchen (45.1%) and not exposed to direct light (94.5%); 23.6% of the kibble feeders said it might be exposed to high temperatures. Most commercial pet food feeders (67.3%) considered preservatives a potential health risk for pets. Among homemade diet feeders, 38.6% stored fish oil at room temperature. Conclusions: Pet owners should be educated in proper food storage management when receiving feeding instructions from veterinarians. More comprehensive information on the nature and importance of additives in pet food should be promoted by manufacturers.

Full text

animals
Article
A Survey among Dog and Cat Owners on Pet Food Storage and
Preservation in the Households
Giada Morelli * , Davide Stefanutti and Rebecca Ricci


Citation: Morelli, G.; Stefanutti, D.;
Ricci, R. A Survey among Dog and
Cat Owners on Pet Food Storage and
Preservation in the Households.
Animals 2021,11, 273. https://
doi.org/10.3390/ani11020273
Academic Editor: Giacomo Biagi
Received: 30 December 2020
Accepted: 19 January 2021
Published: 21 January 2021
Publisher’s Note: MDPI stays neutral
with regard to jurisdictional claims in
published maps and institutional affil-
iations.
Copyright: © 2021 by the authors.
Licensee MDPI, Basel, Switzerland.
This article is an open access article
distributed under the terms and
conditions of the Creative Commons
Attribution (CC BY) license (https://
creativecommons.org/licenses/by/
4.0/).
Department of Animal Medicine, Production and Health, University of Padua, Viale dell’Università16,
35020 Legnaro, Italy; davide.stefanutti@phd.unipd.it (D.S.); rebecca.ricci@unipd.it (R.R.)
*Correspondence: giada.morelli@unipd.it; Tel.: +39-049-827-2532
Simple Summary:
Proper dog and cat food preservation is fundamental to ensure the best quality of
the diet right up to the moment of feeding, given that nutritional value, safety and sensory properties
can be irreparably damaged by environment and time. To this end, a survey was conducted to
explore how pet owners store both commercial and home-prepared diets. On the whole, despite
the wide variability of practices adopted, most of the 2221 respondents implemented good storage
management. Room temperature was the most overlooked parameter during storage, and this
may be a cause of concern because exposure to warmth can enhance rancidity, especially in diet
formulations rich in fats and oils. For this reason, veterinarians should provide precise instructions
on storing perishable ingredients to those who feed home-prepared diets. Moreover, respondents
of older generations appeared to distrust the use of preservatives in commercial pet foods and
often deemed their inclusion harmful and unnecessary. Pet food manufacturers should discour-
age skepticism of the additives crucial to long-term commercial pet food conservation through
better communication.
Abstract:
Background: Pet food storage plays a crucial role in maintaining the nutritional and sensory
properties of purchased products over time. Methods: An online survey was developed to collect
data regarding owners’ storage habits for both commercial and home-made diets. Results: The
questionnaire was completed by 1545 dog owners and 676 cat owners. Pet and owner age played
roles in the choice of the type of diet (commercial vs. home-cooked vs. raw meat-based) adopted.
Kibble feeders (75.7%) usually bought one (50.1%) or two (24.6%) packages at a time, and most
pets (64.4%) took a minimum four weeks to consume an entire bag. Almost half of the owners
(43.5%) used a container to store pet food (plastic bins for 79.5%). Pet food was commonly stored
in the kitchen (45.1%) and not exposed to direct light (94.5%); 23.6% of the kibble feeders said it
might be exposed to high temperatures. Most commercial pet food feeders (67.3%) considered
preservatives a potential health risk for pets. Among homemade diet feeders, 38.6% stored fish oil at
room temperature. Conclusions: Pet owners should be educated in proper food storage management
when receiving feeding instructions from veterinarians. More comprehensive information on the
nature and importance of additives in pet food should be promoted by manufacturers.
Keywords: dog; cat; pet food; storage; survey
1. Introduction
Like food for human consumption, pet food is closely regulated to ensure the highest
standards of hygiene, safety and quality. Along with this objective, European pet food
manufacturers must abide by numerous regulations that involve the entire production
process, from the selection of raw materials to the sale of finished products [
1
]. The ultimate
quality and safety of pet foods are determined by all the measures taken throughout their
production, distribution and use, however. Critical hazards from the first steps in the
supply chain to the final handling before consumption can be identified, and this makes
Animals 2021,11, 273. https://doi.org/10.3390/ani11020273 https://www.mdpi.com/journal/animals

Animals 2021,11, 273 2 of 19
also consumers responsible for preserving the nutritional properties and safety of the food
products together with retailers, distributors and manufacturers [2,3].
The most overlooked players in ensuring pet food quality and safety are the owners,
whose domestic storage and handling habits have been scarcely considered in literary
evidence until now. Even if dry and wet commercial pet foods are sold as nutritionally
adequate and safe, improper management after purchase can worsen their quality [
4
] and
this may eventually place both people and their animals at risk of food-related issues [
3
].
This applies also to the fresh human-grade ingredients used in home-prepared diets, which
may cause a decline in the nutrient and microbial profile of the diet if not managed and
handled properly. Since the consumption of altered foods can negatively affect animal
wellness and health [
4
,
5
], care must be taken to preserve their sensory profile, nutritional
value and microbiological safety until administration to the pet.
Proper pet food storage is paramount to blocking or delaying the development of
degenerative chemical processes and the growth of spoilage microorganisms which lead
to its alteration [
5
,
6
]. Whether intended as commercial product or home-prepared meal,
together with the length of time for which it is suited for consumption, the diet’s nutritional
characteristics mainly define the extent of chemical and microbiological risks to which it
is exposed during storage. Due to the high lipid content and the long shelf life of kibble,
lipid oxidation poses a major spoilage risk for dry pet foods [
3
–
5
]. Lipid oxidation is a
time-dependent degenerative chemical phenomenon that entails major sensory alterations
and a decline of the food’s nutritional value [
3
], and eventually leads to the formation of
compounds with mutagenic and genotoxic potential [
6
–
9
]. Whereas on the other hand
high extrusion temperatures and low moisture content decrease the risk of microbial
contamination in kibbles [
10
], such finished dry pet food products offer a suitable substrate
for Salmonella spp. survival in the long term [
2
–
11
]. Similarly, wet pet foods packaged
in cans, trays and pouches undergo heat processing to achieve commercial sterility by
destroying heat-sensitive pathogens; for this reason, these products should not contain
pathogens at the time of opening.
Home-prepared diets require the use of fresh perishable ingredients, among which meat
is the most fragile owing to its chemical composition that favors microbial contamination
and growth during storage [
12
]. However, home-prepared diets are usually consumed
immediately after preparation; thus, their relatively short storage time makes the threat posed
by spoilage processes less concerning. Moreover, domestic cooking is an effective method
to significantly reduce the microbial contamination of the ingredients. On the contrary, the
microbiological risk is definitely higher for raw meat-based diets (RMBDs), which have
been gaining popularity in recent years among dog and cat owners [
13
], since raw meat
might be contaminated by foodborne pathogens [
14
]. Neither should lipid oxidation be
underestimated for cooked or raw home-prepared diets, due to the widespread use of oils rich
in polyunsaturated fats (PUFAs; e.g., fish oil) which oxidize easily if not stored properly [
15
].
While gathering information on the type of diet most commonly adopted among the
dog and cat owners interviewed, the main goals of this study were to acquire knowledge on
the most popular pet food domestic preservation methods and to point out any criticality in
the storage management of both commercial and home-prepared diets. The behavior of the
owners during pet food purchase and their attitudes to diet preparation and administration
were also investigated.
2. Materials and Methods
2.1. Participant Recruitment and Survey Design
A multiple-choice online survey (Supplementary file S1) in Italian language was
created using Google Forms
©
. The questionnaire was piloted among the authors before its
publication and the results of this test were not considered in the study. The open survey
was shared on a social media (Facebook
©
) for 60 days between December 2018 and January
2019; it was actively promoted to a number of pet enthusiasts, owners and breeders’ groups.
No reference to a specific diet was included in the title of the questionnaire (“Preservation

Animals 2021,11, 273 3 of 19
of foods for dogs and cats”) so that any owner, regardless of the type of diet adopted for
their pet, could volunteer to participate in the study.
The survey began with multiple choice questions (MCQs) that collected information
on demographic data (i.e., gender, age, place of residence, job association with animal care),
pet species (i.e., dog or cat; owners of many animals were asked to fill out the question-
naire by referring to one single pet), pet signalment (i.e., breed, gender, age, size, body
weight, body condition according to the owner) and type of diet administered to the pet
(i.e., commercial dry diet, commercial wet diet, home-cooked diet (HCD), RMBD). Par-
ticipants were then interviewed on the domestic management of pet food depending on
the selected type of diet. Those who used kibbles on a daily basis, whether alone or in
combination with canned pet foods or homemade foods, were invited to answer the dry
food-related MCQs; those who used commercial wet food alone or in combination with
homemade foods were asked to answer the wet pet food-related MCQs. For both groups
(dry food-centered and wet food-centered), an initial set of questions investigated owners’
purchasing and pet feeding habits; a second set of MCQs collected information on the
characteristics of the diet, and a third set of questions examined storage habits. Lastly, three
additional Likert scale questions were included with the aim of collecting opinions on the
use of preservatives in commercial pet food. For those who used a HCD or a RMBD only,
a first set of MCQs aimed at investigating diet formulation, while a second one aimed at
studying meat and fish preservation practices; a third and last set of MCQs investigated
the use of fish oils and vegetable oils and their storage conditions.
In total, the survey contained 118 questions, but the number of questions per partici-
pant varied from 35 to 48 depending on the type of diet selected.
2.2. Data Analysis
The data collected from the survey were transferred to a spreadsheet (Excel, Microsoft)
and underwent descriptive analysis. Quantitative and qualitative data were reported as
frequency (n/N) and percentage (%). Data expressed as percentages were compared among
categories using either the Chi-square test or the Fisher exact test for small samples (SAS
version 9.4). Statistical significance was set at p< 0.05.
3. Results
3.1. Survey Participants
A total of 2221 persons answered the survey, 1545 (69.6%) of whom were dog owners
and 676 (30.4%) were cat owners. Most interviewees were women (87.4%, 1940/2221)
and were 18–34 years old (40.3%, 894/2221). Participants were asked whether their job
dealt with animal care: 4.6% (103/2221) were dog trainers, 2.3% (50/2221) breeders, 2.0%
(44/2221) veterinarians, 1.6% (35/2221) veterinary medicine students and 0.9% (21/2221)
pet groomers. Pet owner demographics are presented in Table 1.
Table 1. Demographics of survey respondents (n= 2221).
Owners, n(%)
Gender Male 281 (12.6)
Female 1940 (87.4)
Age, years old
<18 10 (0.4)
18–34 894 (40.3)
35–44 551(24.8)
45–54 467 (21.0)
55–64 237 (10.7)
>65 62 (2.8)
Geographical distribution
Northern Italy 1397 (62.9)
Central Italy 491 (22.1)
Southern Italy and Islands 301 (13.6)
Other countries 32 (1.4)

Animals 2021,11, 273 4 of 19
3.2. Canine Population
Out of a total of 1545 dogs, males and females were equally represented (51.2% and
48.8%, respectively). The percentage of neutered animals varied widely depending on
gender: most males were intact (78.4%, 619/790), while 56.2% (424/755) of females were
spayed. Roughly, one in five dogs (302/1545) was mongrel, and among 115 different breeds
the most representative was Border Collie (5.8%, 90/1545), followed by Weimaraner and
Labrador Retriever. As regards the age of the dogs, 58 responses were excluded because an
unlikely date of birth was reported. Most dogs were aged between 1 and 7 years (65.1%,
968/1487); the mean age was 46 months for purebred dogs and 64 for mongrels, accounting
for an overall mean of 50
±
41 months. The majority of the dogs were medium size
(10–24 kg, 41.7%), while 29.6% were large size (25–45 kg), 24.1% small size (<25 kg) and
4.7% giant size (>45 kg). Most owners considered the weight of their dogs to be ideal
(85.2%), while 10.1% of the dogs were reported to be overweight, 4.6% underweight and
none obese. Table 2provides a summary of dog demographics.
Table 2. Characteristics of dogs enrolled in the study (n= 1545).
Dogs, n(%)
Gender Male 790 (51.2)
Female 755 (48.8)
Neutering status Neutered/spayed 595 (38.5)
Intact 950 (61.5)
Age
<1 y.o. (puppy) 254 (17.1)
1–7 y.o. (adult) 968 (65.1)
>7 y.o. (senior) 265 (17.8)
Body condition
(according to owner)
Underweight 70 (4.6)
Normal weight 1317 (85.2)
Overweight 156 (10.1)
Most represented breeds(8 out
of 116)
Mongrel 302 (19.5)
Border Collie 90 (5.8)
Weimaraner 69 (4.5)
Labrador Retriever 65 (4.2)
Dachshund 62 (4.0)
French bouledogue 62 (4.0)
German shepherd 48 (3.1)
Boxer 46 (3.0)
3.3. Feline Population
Out of a total of 676 cats, 367 were males (54.3%) and 309 females (46.7%). There was no
evident difference in the rate of neutered cats between males (87.2%) and females (87.7%).
Regarding age, six responses were excluded because an unlikely date of birth was
reported. Evaluation of the 670 valid answers gave the following distribution in age groups:
6.1% of cats were less than 6 months old, 23.5% had an age between 6 months and 2 years,
57.3% were between 2 and 10 years old, and the remaining 13.1% were more than 10 years
old. Most cats (n= 517) were European Shorthair (no pedigree), and the remaining 159 cats
belonged to 23 different breeds. Among these, the most representative was Maine Coon,
followed by Scottish Fold and Norwegian Forest Cat breeds.
Most owners considered the weight of their cats to be ideal (71.3%), while 23.4% of the
cats were reported to be overweight, 4.0% underweight and 1.3% obese. Table 3provides a
summary of cat demographics.

Animals 2021,11, 273 5 of 19
Table 3. Characteristics of cats enrolled in the study (n= 676).
Cats, n(%)
Gender Male 367 (54.3)
Female 309 (46.7)
Neutering status Neutered/spayed 591 (87.4)
Intact 85 (12.6)
Age
<6 m.o. (kitten) 41 (6.1)
6–24 m.o. (junior) 157 (23.5)
2–10 y.o. (adult) 384 (57.3)
>10 y.o. (senior) 88 (13.1)
Body condition
(according to owner)
Underweight 27 (4.0)
Normal weight 482 (71.3)
Overweight 167 (24.7)
Most represented breeds(7 out
of 24)
European Shorthair, no
pedigree 517 (76.4)
Maine Coon 44 (6.5)
Scottish Fold 15 (2.2)
Norwegian Forest Cat 14 (2.1)
Ragdoll 10 (1.5)
Siberian 10 (1.5)
Persian 9 (1.3)
3.4. Types of Diets and Demographics
The majority of pet owners (75.7%, 1682/2221) fed their pets kibble. Among them,
37.7% (634/1682) relied exclusively on dry pet food, while 35.3% (594/1682) mixed dry and
wet pet food, 14.0% (236/1682) mixed kibble and homemade diet, and 13.0% (218/1682)
mixed dry and wet pet food and homemade diet.
The remaining participants (24.3%, 539/2221) who did not feed any kibble were
distributed as follows: commercial wet pet food only: 1.8%, 39/2221; commercial wet pet
food mixed with homemade diet: 1.9%, 42/2221; HCD: 10.0%, 222/2221 (214 dog owners
and 8 cat owners), and RMBD: 10.6%, 236/2221 (207 dog owners and 29 cat owners).
The distribution of the diets based on demographics is shown in Table 4.
The Chi Square test highlighted a significant relationship (p= 0.0004) between the
dog’s diet and the age of the owner. The incidence of feeding dry food (either as single or
additional component of the diet) was higher among the under-35s (75.4%, 492/652) but
lower among people between 35 and 64 years (64.3%, 545/847) and among the over-65s
(59.6%, 28/47). Conversely, feeding a HCD was more common among the older sections
of the population, especially the over-65s (29.7%, 14/47), where it reached a much higher
percentage than in other age groups. With the exception of the over-65s (8.5%, 4/47),
RMBDs were preferred equally by all sections of the population. No significant relationship
emerged between the age of the owner and the cat’s diet instead.
Another significant item of evidence (p< 0.0001) was found between type of diet and
dog’s age: kibbles were preferred for feeding puppies rather than adult and senior dogs.
As regards the relationship between age and diet in cats, canned food-based diets
were more popular among senior cats (12.5%, 11/88) and kittens (4.9%, 2/41), while among
junior subjects and adults the prevalence of this diet did not reach 2% (p= 0.0004). HCDs
and RMBDs were quite unpopular among cat population at any life stage.

Animals 2021,11, 273 6 of 19
Table 4.
Distribution of the types of diets offered to dogs and cats (
n
/%) based on owner’s and pet’s age.
Dry Pet Food
n(%)
Wet Pet Food
n(%)
HCD
n(%)
RMBDs
n(%)
Species Dog 1064 (68.8) 60 (3.9) 214 (13.8) 207 (13.4)
Cat 618 (91.4) 21 (3.1) 8 (1.2) 29 (4.3)
Dog
Owner’s age
<18 9 (100) 0 (0) 0 (0) 0 (0)
18–34 482 (75.1) 15 (2.3) 61 (9.5) 84 (13.0)
35–44 244 (66.6) 15 (3.9) 57 (15.8) 50 (13.7)
45–54 197 (62.3) 19 (6.1) 55 (17.4) 45 (14.2)
55–64 104 (63.0) 10 (6.1) 27 (16.4) 24 (14.5)
>65 28 (59.6) 1 (2.2) 14 (29.7) 4 (8.5)
Dog’s age
<1 y.o. 209 (82.3) 3 (1.2) 21 (8.3) 21 (8.3)
1–7 y.o. 650 (67.1) 40 (4.1) 134 (13.9) 144 (14.9)
>7 y.o. 187 (62.7) 15 (5.0) 56 (18.8) 40 (13.4)
Cat
Owner’s age
<18 1 (100) 0 (0) 0 (0) 0 (0)
18–34 237 (94.0) 6 (2.4) 0 (0) 9 (3.6)
35–44 170 (91.9) 4 (2.2) 3 (1.6) 8 (4.3)
45–54 133 (88.1) 7 (4.6) 4 (2.7) 7 (4.6)
55–64 63 (87.5) 3 (4.2) 1 (1.4) 5 (6.9)
>65 14 (93.3) 1 (6.7) 0 (0) 0 (0)
Cat’s age
<6 m.o. 36 (87.8) 2 (4.9) 0 (0) 3 (7.3)
6–24 m.o. 146 (93.0) 2 (1.3) 3 (1.9) 6 (3.8)
2–10 y.o. 356 (92.7) 6 (1.6) 4 (1.0) 18 (4.7)
>10 y.o. 74 (84.1) 11 (12.5) 1 (1.1) 2 (2.3)
3.5. Dry and Wet Pet Food-Based Diet: Selection, Management and Purchase
Questions on dry pet food were answered by 1682 people but due to a technical
problem, the 236 owners feeding their pet kibbles mixed with home-prepared food could
not answer the 14 questions related to selection, management and purchase (i.e., questions
22 to 35, Sections 5 and 6 of the survey); therefore, only 1446 answers were taken into
consideration. The majority of the owners who gave their animals kibble as single or
additional component of the diet habitually fed their pet twice a day (48.4%, 700/1446);
22.1% (320/1446) preferred ad libitum feeding, 19.1% (276/1446) administered three meals
per day, 5.4% (78/1446) more than three meals per day, and the remaining 5.0% (72/1446) a
single daily meal.
The quantity of dry food administered was mainly based on personal experience
(42.0%, 607/1446) and packaging indications (33.5%, 484/1446), while one owner out of
four (24.5%, 355/1446) relied on the advice of the veterinarian. Doses were measured
on a kitchen scale (29.6%, 428/1446), by eye (28.4%, 411/1446) or using a measuring cup
(28.0%, 405/1446); 14.0% (202/1446) of the participants did not consider measuring dry pet
food at all.
The pet shop was selected as the preferred point of dry pet food purchase (60.7%,
877/1446), while large retailers (i.e., supermarkets, convenience stores) were chosen by
10.7% (155/1446) of the participants; other common purchase methods were internet
shopping (25.4%, 368/1446) and door-to-door selling (3.2%, 46/1446).
Half of the owners purchasing dry pet food for their dog or cat habitually bought
one pack at a time (50.1%, 724/1446), while the others used bought at least two (24.6%,
356/1446), or three or more (25.3%, 366/1446). The most purchased kibble bag sizes
weighed more than 11 kg (36.1%, 522/1446) and 1–2 kg (23.6%, 341/1446); other common
bag sizes weighed less than 1 kg (17.3%, 250/1446), 3–6 kg (13.7%, 198/1446) and 7–10 kg
(7.9%, 115/1446). A significant relationship (p< 0.0001) was found between kibble bag
size and pet species, as bags weighing less than 6 kg were preferred by cat owners (63.4%,
500/789) while those weighing over 6 kg were much more often purchased by dog owners
(87.3%, 556/637). A significant relationship (p< 0.0001) was also observed between kibble

Animals 2021,11, 273 7 of 19
bag size and dog size, as bags weighing less than 6 kg were preferred for small size dogs
(52.9%, 153/289) while those weighing over 6 kg were mainly purchased for medium and
maxi size dogs (82.7%, 460/556). Giant dog owners purchased only bags that weighed
between 11 and 15 kg (n= 29) or more than 15 kg (n= 13).
Twenty respondents (1.4%) reported purchasing bulk kibble sold in pet stores, and
most were cat owners (70.0%, 14/20). Most animals took at least four weeks to consume an
entire dry food pack (64.4%, 931/1446) while some required less than two weeks (22.5%,
326/1446) or two to four weeks (13.1%, 189/1446). The Chi Square test highlighted a
significant relationship (p< 0.0001) between time taken to consume a whole pet food bag
and animal species. Most of the dogs took one month or more to consume a package
(71.8%, 611/851) while in cats this percentage was considerably lower (53.8%, 320/595). As
regards differences among the dog sizes, no clear trend was found.
As for the dry food type currently fed, standard maintenance pet food was the most
popular (43.3%, 626/1446); 20.5% of the owners (296/1446) reported using a grain-free prod-
uct, 14.2% a calorie-restricted product (205/1446) and 13.1% a dietetic product (189/1446),
while vegan and vegetarian formulations were chosen by 0.4% of the interviewees (6/1446).
The four most common dietetic pet foods were those formulated for the management of
gastrointestinal diseases (4.8%, 70/1446), kidney diseases (3.7%, 53/1446), obesity (3.1%,
45/1446) and dermatological disorders (2.8%, 41/1446). Single-protein formulations were
chosen by 39.9% of the respondents (578/1446), while one in four owners (24.7%, 357/1446)
could not say whether the food in use included limited ingredients or not.
The choice of dry food type was mainly influenced by the owner’s personal experience
(27.2%, 393/1446), the veterinarian’s advice (23.8%, 345/1446) and information available on
internet (17.2%, 249/1446). Some people followed advice from breeders (8.4%, 121/1446),
shop assistants (7.3%, 105/1446) and friends or relatives (3.9%, 56/1446); the remaining
12.2% (176/1446) stated other reasons.
Questions about wet pet food were answered by 81 people, including 60 dog owners
and 21 cat owners. Most animals fed canned foods were usually given two (60.5%, 49/81)
or more (29.6%, 24/81) meals per day, while 6.2% (5/81) were given a single daily meal and
3.7% (3/81) were fed ad libitum. The daily ration was determined by the owner’s expertise
(56.8%, 46/81), indications on the packaging (23.5%, 19/81) or the veterinarian’s advice
(19.8%, 16/81). Wet foods were mainly purchased at pet shops (46.9%, 38/81) and online
shops (35.8%, 29/81), while large retailers were preferred to lesser extent (17.3%, 14/81).
Regular maintenance (58%, 47/81) and grain-free (23.5%, 19/81) were the most com-
mon wet food types; among dietetic products (9.9%, 8/81), those for kidney and gastroin-
testinal diseases prevailed (n= 4 each), followed by formulations for diabetic subjects
(n= 2). Calorie-restricted products were purchased by 3.7% (3/81) while the remaining
4.9% bought other types of wet food (4/81). Single-protein formulations were chosen by
38.3% of the respondents (31/81, while eleven owners (13.6%) could not say whether the
food in use included limited ingredients or not.
Personal experience (42.0%, 34/81) and internet searches (28.4%, 23/81) were the main
determining factors in product choice while 17.3% (14/81) selected the food based on other
reasons, such as other people’s advice or the preference shown by the pet. The remaining
12.3% (10/81) purchased the products recommended by the veterinarian.
The most common packaging types were rigid cans (58.0%, 47/81), aluminum trays
(25.9%, 21/81) and pouches (16.1%, 13/81). The most purchased formats weighed between
100 and 400 g (50.6%, 41/81), or more than 400 g but less than 1 kg (24.7%, 20/81); 19.8%
(16/81) of the owners reported using formats weighing less than 100 g while 4.9% (4/81)
bought packages weighing more than 1 kg.
3.6. Dry and Wet Pet Food-Based Diet: Storage
As for the storage of dry pet food, more than half of the kibble feeders reported
keeping the product in its original package (56.5%, 951/1682), while others moved it
partially (23.0%, 387/1682) or totally (20.5%, 344/1682) to another container. The most

Animals 2021,11, 273 8 of 19
popular alternative containers were bins made of plastic (79.5%, 581/731) or tin (14.8%,
108/731), and a minority of the interviewees (5.7%, 42/731) said they used automatic
pet feeders, glass containers or nylon bags. The pet food package in use was gener-
ally closed using clothespins, adhesive tape or rubber bands (43.8%, 586/1338) or the
resealable zip lock included (40.1%, 536/1338); 1.8% (25/1338) used alternative methods
(e.g., tinfoil). Some owners either just rolled the edges of the bag (11.0%, 147/1338) or did
not close it at all (3.3%, 44/1338). The original packaging was a cardboard box in 24.8% of
cases (417/1682).
Kibbles were stored inside the house, more precisely in the kitchen (45.1%, 758/1682),
in a closet (31.8%, 535/1682) or in other rooms (16.0%, 269/1682); conversely, some inter-
viewees stored kibbles outside the house in a closed environment (e.g., the garage; 6.7%,
113/1682) or outdoors (0.4%, 7/1682). The pet food bag was commonly placed inside a
cabinet (52.7%, 885/1682) or another container (16.9%, 285/1682) or else kept on the ground
by 30.4% of the respondents (512/1682; 320 of which in direct contact with the floor).
According to 94.5% of the owners (1590/1682), the pet food was not exposed to light.
Also, the pet food was not positioned near heat sources (92.2%, 1552/1682), and the tempera-
ture of the room where it was stored allegedly never exceeded 30 ◦C (76.4%, 1286/1682).
One in ten interviewees (10.2%, 171/1682) reported perceiving anomalous or unpleas-
ant smells at least once when opening an unexpired package, while 6.8% (115/1682) stated
that malodors developed during the regular use of the product. Insects or larvae were
found by 4.2% (70/1682) respondents at the first opening of an unexpired package, and by
3.0% (51/1682) during its use.
Four out of ten owners (39.1%, 658/1682) believed kibbles could be consumed for
up to two months after opening the package, 33.4% (562/1682) for up to one month and
27.5% (462/1682) for more than two months after opening. A minority of interviewees
(10.6%, 179/1682) reported that they never looked at the expiration date on the package,
and another 7.2% (121/1682) declared they gave expired kibble to their pets.
Over one in three owners (34.4%, 579/1682) deemed their pets to be more attracted
to kibbles from newly-opened packages rather than those from long-opened packages;
this percentage drops to 28% when considering dogs and rises to 46% for cats. Another
19.0% (319/1682) was unable to determine whether the pet showed any preference, and
according to the remaining 46.5% (784/1682) there was no such difference.
As for the management of leftover kibbles, 52.1% (876/1682) of the owners left them
in the bowl to be consumed later by the pet, while 22.4% (377/1682) tossed them in the
trash; the others stored them out of the bowl at room temperature (21.9%, 369/1682) or in
the refrigerator (3.6%, 60/1682) until the following meal.
Wet pet food storage was not an issue for one third of the interviewees (30.9%, 25/81)
since they used single-dose packs. Among the remaining 56 people, 91.1% (51/56) kept
the unfinished packages in the refrigerator; the refrigerated food was usually warmed
up before consumption by the pet (72.6%, 37/51). The majority of owners (85.7%, 48/56)
stored the unfinished packages after closing them with different methods (e.g., plastic
wrap, tinfoil, clothespins, plastic bags); six owners (10.7%) moved the remaining food to an
airtight container and two (3.6%) did not close the package at all. Among those who did
not use single-dose packs, 71.4% (40/56) stored the unfinished packages for up to one day,
14.3% (8/56) for up to two days and 14.3% (8/56) for more than two days. According to
82.7% (67/81) of the people answering the questions on wet pet foods, these products were
never exposed to temperatures above 30 ◦C.
As for the management of leftover wet food, 45.7% (37/81) tossed it in the trash,
29.6% (24/81) left it in the bowl and 24.7% (20/81) stored and administered it with the
following meal.
3.7. Owners’ Opinions on the Use of Preservatives in Commercial Pet Food
Answers to Likert scale questions showed that 25.2% (444/1763) of the pet owners
who used commercial pet foods trusted the use of preservatives in these products as

Animals 2021,11, 273 9 of 19
necessary for optimal preservation, while 36.9% (650/1763) disagreed with this claim and
37.9% (669/1763) did not take a clear stance on the statement (Figure 1). A significant
relationship (p< 0.0001) emerged between this affirmation and the respondents’ age, as
the percentage of those who did not think preservatives were necessary was significantly
higher among participants more than 45 years old (44.5%, 258/580) than among those
younger (33.1%, 392/1183).
Animals 2021, 11, 273 9 of 19
As for the management of leftover wet food, 45.7% (37/81) tossed it in the trash, 29.6%
(24/81) left it in the bowl and 24.7% (20/81) stored and administered it with the following
meal.
3.7. Owners’ Opinions on the Use of Preservatives in Commercial Pet Food
Answers to Likert scale questions showed that 25.2% (444/1763) of the pet owners
who used commercial pet foods trusted the use of preservatives in these products as nec-
essary for optimal preservation, while 36.9% (650/1763) disagreed with this claim and
37.9% (669/1763) did not take a clear stance on the statement (Figure 1). A significant rela-
tionship (p < 0.0001) emerged between this affirmation and the respondents’ age, as the
percentage of those who did not think preservatives were necessary was significantly
higher among participants more than 45 years old (44.5%, 258/580) than among those
younger (33.1%, 392/1183).
A small minority of the respondents (6.7%, 118/1763) believed that preservatives
were not harmful to the pet’s health, while 67.3% (1185/1763) considered preservatives a
potential health risk for pets; 26.1% (460/1763) could neither agree nor disagree with this
statement (Figure 2). Again, a significant relationship between the statement “preserva-
tives can be harmful to the pet’s health” and the age of the respondents was found (p <
0.0001): whereas only one in five of participants younger than 45 (20.8%, 246/1183) firmly
agreed, the belief was shared by more than one out of three older owners (34.8%, 202/580).
Lastly, 69.1% of the latter group (1217/1763) believed preservatives in pet foods to consist
mostly or entirely of chemicals, while only 4.8% (85/1763) thought they were mainly of
natural origin; 26.1% (461/1763) considered them half chemical, half natural.
Figure 1. Degree of agreement for each age bracket with the statement: “the use of preservatives in
pet food is necessary for optimal preservation”.
0%
20%
40%
60%
80%
100%
<18 years 18-34 years35-44 years45-54 years55-64 years >65 years
Strongly agree Agree
Neither agree nor disagree Disagree
Strongly disagree
Figure 1.
Degree of agreement for each age bracket with the statement: “the use of preservatives in
pet food is necessary for optimal preservation”.
A small minority of the respondents (6.7%, 118/1763) believed that preservatives
were not harmful to the pet’s health, while 67.3% (1185/1763) considered preservatives a
potential health risk for pets; 26.1% (460/1763) could neither agree nor disagree with this
statement (Figure 2). Again, a significant relationship between the statement “preservatives
can be harmful to the pet’s health” and the age of the respondents was found (p< 0.0001):
whereas only one in five of participants younger than 45 (20.8%, 246/1183) firmly agreed,
the belief was shared by more than one out of three older owners (34.8%, 202/580). Lastly,
69.1% of the latter group (1217/1763) believed preservatives in pet foods to consist mostly
or entirely of chemicals, while only 4.8% (85/1763) thought they were mainly of natural
origin; 26.1% (461/1763) considered them half chemical, half natural.
Animals 2021, 11, 273 10 of 19
Figure 2. Degree of agreement for each age bracket with the statement: “the presence of preserva-
tives in pet food could be harmful to my pet’s health”.
3.8. Home-Cooked Diet: Management, Purchase and Storage
A total of 222 people filled in this section of the survey. The main reason why these
owners fed their pets a HCD was their lack of trust in commercial pet food (44.6%, 99/222);
otherwise, this type of diet was chosen in support of the pet’s health issues (36.9%, 82/222),
overcoming the pet’s palatability issues (e.g., the animal refused to eat commercial pet
food, 12.6%, 28/222) or by following the veterinarian’s advice (5.9%, 13/222).
Over one third of the owners (36.5%, 81/222) trusted a veterinary nutritionist for the
formulation of the diet, while 24.8% (55/222) relied on their veterinarian and 14.0%
(31/222) turned to an online nutritionist consultant. The others relied on their own exper-
tise (11.7%, 26/222), information available on internet (6.8%, 15/222) or specific books
(6.3%, 14/222).
As regards the feeding schedule, most dogs were fed twice a day (75.2%, 167/222),
while 5.9% (13/222) of the owners administered one meal per day and 18.9% (42/222) three
or more. The quantity of food provided was generally weighed with a kitchen scale
(78.8%, 175/222); alternatively, 18.0% (40/222) of the daily rations were defined by eye and
3.2% (7/222) were not measured at all. Fish was included in the diet by 79.3% of the HCD-
feeders (176/222). Solid fats were used by 22.5% of the owners (50/222); those most com-
monly used were butter (6.8%, 15/222) and lard (5.4%, 12/222). Half of the interviewees
(52.3%, 116/222) bought the meat or fish at the supermarket, 35.1% (78/222) from the
butcher or fishmonger and 1.4% (3/222) on internet; 11.3% (25/222) patronized all the
above.
Most respondents (80.6%, 179/222) bought fresh meat and fish to be frozen at home,
while the minority purchased and stored only fresh ingredients (16.2%, 36/222), or bought
them already frozen (3.2%, 7/222).
Except for those who used only fresh ingredients, the meat was generally stored in
the freezer for no longer than one month (81.2%, 151/186) or three months (18.8%, 35/186)
and allowed to defrost in the refrigerator (50.0%, 93/186) or at room temperature (44.6%,
83/186), while the remaining 5.4% of respondents defrosted it using the microwave or hot
water. About half of the interviewees prepared the daily rations in advance and stored
them cooked in the fridge (21.6%, 48/222) or in the freezer (30.2%, 67/222), while the other
half (48.2%, 107/222) prepared the meals one by one. As for managing leftovers, 48.2%
(107/222) of the participants tossed them in the trash, 40.5% (90/222) stored them until the
following meal, and 11.3% (25/222) left them in the bowl to be consumed later by the pet.
0%
10%
20%
30%
40%
50%
60%
70%
80%
90%
100%
<18 years 18-34 years 35-44 years 45-54 years 55-64 years >65 years
Strongly agree Agree
Neither agree nor disagree Disagree
Strongly disagree
Figure 2.
Degree of agreement for each age bracket with the statement: “the presence of preservatives
in pet food could be harmful to my pet’s health”.

Animals 2021,11, 273 10 of 19
3.8. Home-Cooked Diet: Management, Purchase and Storage
A total of 222 people filled in this section of the survey. The main reason why these
owners fed their pets a HCD was their lack of trust in commercial pet food (44.6%, 99/222);
otherwise, this type of diet was chosen in support of the pet’s health issues (36.9%, 82/222),
overcoming the pet’s palatability issues (e.g., the animal refused to eat commercial pet
food, 12.6%, 28/222) or by following the veterinarian’s advice (5.9%, 13/222).
Over one third of the owners (36.5%, 81/222) trusted a veterinary nutritionist for the
formulation of the diet, while 24.8% (55/222) relied on their veterinarian and 14.0% (31/222)
turned to an online nutritionist consultant. The others relied on their own expertise (11.7%,
26/222), information available on internet (6.8%, 15/222) or specific books (6.3%, 14/222).
As regards the feeding schedule, most dogs were fed twice a day (75.2%, 167/222),
while 5.9% (13/222) of the owners administered one meal per day and 18.9% (42/222)
three or more. The quantity of food provided was generally weighed with a kitchen scale
(78.8%, 175/222); alternatively, 18.0% (40/222) of the daily rations were defined by eye
and 3.2% (7/222) were not measured at all. Fish was included in the diet by 79.3% of
the HCD-feeders (176/222). Solid fats were used by 22.5% of the owners (50/222); those
most commonly used were butter (6.8%, 15/222) and lard (5.4%, 12/222). Half of the
interviewees (52.3%, 116/222) bought the meat or fish at the supermarket, 35.1% (78/222)
from the butcher or fishmonger and 1.4% (3/222) on internet; 11.3% (25/222) patronized
all the above.
Most respondents (80.6%, 179/222) bought fresh meat and fish to be frozen at home,
while the minority purchased and stored only fresh ingredients (16.2%, 36/222), or bought
them already frozen (3.2%, 7/222).
Except for those who used only fresh ingredients, the meat was generally stored in
the freezer for no longer than one month (81.2%, 151/186) or three months (18.8%, 35/186)
and allowed to defrost in the refrigerator (50.0%, 93/186) or at room temperature (44.6%,
83/186), while the remaining 5.4% of respondents defrosted it using the microwave or hot
water. About half of the interviewees prepared the daily rations in advance and stored
them cooked in the fridge (21.6%, 48/222) or in the freezer (30.2%, 67/222), while the other
half (48.2%, 107/222) prepared the meals one by one. As for managing leftovers, 48.2%
(107/222) of the participants tossed them in the trash, 40.5% (90/222) stored them until the
following meal, and 11.3% (25/222) left them in the bowl to be consumed later by the pet.
3.9. Raw Meat-Based Diets: Management, Purchase and Storage
Two hundred and thirty-six respondents fed their pets a raw diet. There were three
main reasons behind their choice: the first was the belief that RMBDs are the most bio-
logically appropriate diets for dogs and cats owing to their ancestors’ carnivorous nature
(42.4%, 100/236); the second was their distrust of commercial pet food (25.0%, 59/236), the
third regarded their pets’ health problems (24.6%, 58/236). A small minority chose it on a
veterinarian’s advice (3.8%, 9/236) or because the pet refused to eat kibbles (2.5%, 6/236)
or because the pet was weaned on this diet by the breeder (1.7%, 4/236). The most common
RMBD type was the BARF diet (83.9%, 198/236) followed by the Paleo Diet (2.1%, 5/236),
the Prey-Model Diet (1.3%, 3/236) and the Ultimate Diet (0.4%, 1/236); the remaining
12.3% owners (29/236) fed their pets raw meat products without following any particular
diet theory.
About one third of the owners (36.9%, 87/236) trusted a veterinary nutritionist for
the formulation of the diet, 5.9% (14/236) relied on their own veterinarian and 7.2%
(17/236) on an online nutritionist consultant. The other half of the respondents instead
opted for homemade recipes formulated according to indications in books (19.9%, 47/236),
information available on internet (19.9%, 47/236) or their own expertise (10.2%, 24/236).
As regards the feeding schedule, most dogs were fed twice a day (68.6%, 162/236),
while 17.8% (42/236) of the owners administered one meal per day and 13.6% (32/236)
three or more. The quantity of food provided was generally weighed with a kitchen scale
(91.1%, 215/236); alternatively, 7.6% (18/236) of the daily rations were defined by eye and

Animals 2021,11, 273 11 of 19
1.3% (3/236) not measured at all. Fish was included in the diet by 89% of the RMBD-feeders
(210/236). Solid fats were used by 43.2% of the owners (102/236), the most common were
lard (11%, 26/236), tallow (6.4%, 15/236) and butter (5.1%, 12/236). Meat and fish were
purchased from the butcher or fishmonger (30.0%, 71/236), at the supermarket (20.8%,
49/236), on internet (7.6%, 18/236), or from any of these places (41.5%, 98/236).
Most respondents (85.6%, 202/236) bought fresh meat and fish to be frozen at home,
while the minority purchased them already frozen (9.3%, 22/236) or bought and stored
only fresh ingredients (5.1%, 12/236). Except for those who used only fresh ingredients,
the meat was stored in the freezer for no longer than one month by 54.0% (121/224) of
the participants and for no more than three months by 26.8% (60/224); 19.2% (43/224)
stored it for more than three months. The food was defrosted in the refrigerator (52.7%,
118/224) or at room temperature (42.4%, 95/224), while the remaining 4.9% (11/224) of the
respondents used the microwave or hot water. Almost half of the owners (45.5%, 102/224)
reported having a separate freezer for storing the meat intended for their pets.
As for the sanitary precautions taken by the owners when handling raw meat, 30.5%
(72/236) used gloves and 25.4% (60/236) prepared the pet’s diet on a different work table
than the one used for human meals. Whether the diet was formulated by the pet owner or
the veterinarian made no difference in the proportion of people using gloves (p= 0.2580)
and different working tables (p= 0.3697) during preparation.
The daily rations were prepared in advance and then stored in the refrigerator or
the freezer by 58.9% (139/236) of participants, while 41.1% (97/236) prepared the meals
one by one.
Leftovers were generally included in the following meal (58.0%, 137/236) or tossed
in the trash (37.3%, 88/236), while a small minority left them in the bowl at the animal’s
disposal (4.7%, 11/236).
3.10. Use and Storage of Fish Oils and Vegetable Oils
Among the owners who chose a HCD or a RMBD for their pet, 62.2% (285/458)
purchased omega-3 fatty acids supplements in the form of pearls or drops (31.7%, n/285),
fish oil (19.7%, 140/285) or both (10.9%, n/285). The supplementation of omega-3 fatty
acids was equally spread among HCD-feeders (64.4%, 143/222) and RMBD-feeders (60.2%,
142/236), as well as among cat (64.9%, 24/37) and dog (62.0%, 261/421) owners.
The most commonly used fish oils were salmon oil (75.7%, 106/140), cod liver oil
(20.0%, 28/140) and krill oil (14.3%, 20/140); two people used a seaweed-derived oil (1.4%).
Fish oil was stored in the refrigerator by 61.4% (86/140) and at room temperature by
38.6% of the respondents (54/140); such percentage did not vary much between those who
formulated the diet themselves (41.5%) and those who relied on a veterinarian (37.3%).
Over half of the owners (54.3%, 76/140) used the fish oil no later than one month after first
opening and 18.6% (26/140) no later than two months; almost one third of participants
(27.1%, 38/140) used it for more than two months. The fish oil packaging was transparent
in 22.1% of cases (31/236). The fish oil was generally not exposed to light (97% of cases,
136/140) and temperatures above 30 ◦C (92.1%, 129/140).
The majority of respondents (69.2%, 317/458) used at least one vegetable oil, with
a greater diffusion among HCD-feeders (80.6%, 179/222) than RMBD-feeders (58.5%,
138/236). Owners who relied on a veterinarian for the formulation of the diet (74.4%,
212/285) were more likely to use vegetable oils than those who formulated the diet by
themselves (60.7%, 105/173) (p= 0.0029).
The most common vegetable oil types were olive oil (n= 157), sunflower oil (n= 130),
coconut oil (n= 117), flaxseed oil (n= 106) and corn oil (n= 58). Vegetable oils were stored
at room temperature by 79.8% of the respondents (253/317) and in the refrigerator by
20.2% (64/317). Most owners (77.9%, 247/317) used the vegetable oil no later than two
months after opening; the remaining 22.1% (70/317) used it for more than two months. The
vegetable oil packaging was transparent in 35.0% of cases (111/317). The vegetable oil was
generally unexposed to light (95.6%, 303/317) and high temperatures (87.1%, 276/317).

Animals 2021,11, 273 12 of 19
4. Discussion
To the best of the authors’ knowledge, domestic pet food storage practices have not yet
been considered in literature. This survey was intended to disclose how owners manage
food for their pets from purchase to disposal and to highlight certain crucial points that
can lead to food spoiling and unhygienic practices at home.
4.1. Diet Choice for Dogs and Cats and Its Relationship to Demographics
This survey provided evidence that the most common diet type used for both dogs and
cats was kibble, which was fed either alone or in combination with canned food, and this
finding is consistent with the latest official report drafted in Italy [
16
]. The percentage of
owners who chose to feed a homemade diet (27.2%) has increased substantially compared
to previous surveys conducted in Western countries [
17
–
20
]. The choice of a raw diet has
become markedly popular in recent years, and almost equal numbers of RMBD-feeders
and HCD-feeders were found in this study. The different prevalence of alternative diets in
canine and feline populations should be noted, however, given that homemade diets were
very scarcely adopted for cats but amounted to almost one third of the recruited dogs’ regi-
mens. This difference between the two species has been reported in a previous study [
21
]
and can be explained by the fact that the flavor and texture preferences of individual cats
are often influenced by early experience that can affect preferences throughout life [
22
].
Cats accustomed to a specific texture or type of food (i.e., moist, dry, semi-moist) may
refuse foods with different features, so switching their diet from commercial to homemade
may be more difficult than it is in dogs.
According to our findings, owner age and pet age were both correlated with the type
of diet offered to the animal, even if some differences emerged between the two species.
In particular, the use of industrial diets decreased as the dog’s owner aged. The
younger segments of the population were instead more at ease in buying commercial
pet food, probably because it offers a practical, time-saving-time solution better suited
to the lifestyle of their age brackets. Commercial pet food may also be more commonly
viewed as the routine pet feeding solution by younger generations grown used to seeing
well-established products on the market, as opposed to many members of older genera-
tions who still remember when pets were commonly fed leftovers or other food shunned
by the family.
It is interesting to note that whereas over-65s relied more on HCDs than any other
respondent group, they favored RMBDs less than any other. The preference for HCDs in
the older age bracket probably reflects the fact that they have more time to prepare meals
than young owners, who prefer the convenience of kibble for such reason. The reluctance
of over-65s to follow the new RMBD trend is probably also due to the lower internet usage
by this age bracket [23] and consequent less familiarity with new trends.
The lack of relationship between owner’s age and cat’s diet probably continued to
depend on the strong influence that early experience has on a cat’s dietary preferences
throughout life. As regards the influence of the pet’s age on dietary preferences, puppies
have been mainly fed industrial dry foods: this could be due to the convenience and
the perceived safety of using a well-balanced diet specifically formulated to the needs of
growing pets. Conversely, canned foods and HCDs have been more commonly adopted
for senior dogs, probably to deal with aging-related issues such as periodontal diseases
and taste and smell decline while avoiding the consumption of firm-textured foods such as
kibbles. The same reasons can be used to explain the wider diffusion of commercial wet
diets among older cats.
4.2. Dry and Wet Pet Food-Based Diets
This survey found evidence of widespread use of grain-free and single-protein pet
foods. The use of grain-free diets has gained great popularity in the past few years and
this has in part been encouraged by pet food companies, which have been releasing more
and more high protein “ancestral diets”, even if there is no scientific evidence to support

Animals 2021,11, 273 13 of 19
that feeding a grain-free diet is healthier than feeding its grain inclusive counterpart [
24
].
Although single-protein diets were originally formulated to diagnose and support specific
food adverse reactions [
25
], they are commonly administered to healthy pets even if
there is no evidence of extra benefits than those offered by standard maintenance foods.
Moreover, one in four kibble feeders was unable to say whether the product they used
was single-protein or not, meaning that a significant number of consumers was unaware
of the significance and/or practicality of this feature that is increasingly emphasized
on packaging.
As for dry pet food preservation, only a minority of owners stocked up kibble in
large quantities at home, since the majority preferred to buy only one or two packages at a
time. Half of the purchased pet food bags purchased weighed more than 5 kg, however,
and in almost two out of three cases the animal took at least four weeks to consume an
entire package. The long-term use of opened pet food packages (especially in the case of
dogs, who usually took more time than cats to consume a package) combined with the
owner’s belief that the quality of the kibbles remains unaltered for several months after
opening increase the importance of adequate food preservation. Overall, it can be said
that almost every owner was diligent in closing the original packaging, thus preventing
environmental contamination and reducing air exposure. The habit of storing kibble in a
dedicated container was quite widespread, with bins in plastic much more common than
those in tin. Between the two, plastic is probably the better material for storing kibble.
Metals can accelerate the oxidative process on the food substrates they come in contact
with [
26
]. The characteristics of the original packaging also played a non-secondary role
since it was still used after the opening to contain all or some kibbles by eight out of ten
owners. Although modern multi-material packaging is practical and ensures the best
product preservation, cardboard packaging appears to be still quite common, even if it is
not the most appropriate choice to protect kibbles from ambient humidity [
27
]. The owners
interviewed also reported taking care to avoid exposure to light and heat, but nearly one
out of two kept some dry pet food in the kitchen, usually one of the warmest rooms in
the house. One out of four owners admitted that they could not be sure that the food was
never exposed to temperatures above 30
◦
C in the summer. All things considered, exposure
to light seemed the best managed critical point in kibble storage, whereas exposure to
humidity and heat appeared less under their control.
Palatability is related to sensory properties such as flavor, aroma and texture, which
can be strongly influenced by storage condition [
28
]. Even when storage conditions are
satisfactory, the deterioration process progresses inevitably from when the bags are opened.
Over time, pet food deterioration can lead to negative palatability [
5
], as the organoleptic
qualities are inevitably affected, and this is probably perceived earlier by the animal, whose
senses are sharper than a human’s. It is therefore only reasonable that one third of the
owners thought their pet was more attracted to kibble from newly-opened bags than kibble
from sacks open for a long time. Although this result depended on owners’ individual
sensitivity to alterations in their pet’s feeding behavior, it was even more consistent for
the feline population, in which half of the cats was reported to prefer dry pet food from
newly-opened bags.
Anomalies in kibble such as unpleasant odors and the presence of insects were rare
but not absent and were more frequently noticed at the opening of the packages than
during subsequent use. Dry pet food provides a suitable substrate for the reproduction of
storage mites [
29
–
31
] and environmental conditions were clearly proven to be a major factor
involved in their contamination: high temperature (25–30
◦
C) and humidity (80%) were
shown to foster the growth of this pest [
29
,
31
]. Storage mites are also considered important
allergens for dogs with atopic dermatitis [
32
]; therefore, the importance of storing kibble
properly should be stressed to the owners, especially when the products are intended for
animals with sensitivities.
Only a small minority of those interviewed adopted a canned food-based diet, prob-
ably due also to the higher maintenance cost of this type of diet, especially for large and

Animals 2021,11, 273 14 of 19
giant size dogs. Almost one in three owners used single-dose pet food packages, raising
no storage issues after opening. Among the others, the preservation of wet pet foods can
be considered satisfactory as cans were generally lidded, stored in the refrigerator for a
maximum of one day and heated before being fed to the pet. It can be argued that the
storage of wet pet food presents fewer after-opening criticalities due to the small sizes
of the packages that allow the rapid consumption of the products; however, given the
high water content, it should be noted that canned food provides an optimal substrate for
the growth of spoilage microorganisms [
33
], thus the enforcement of proper preservation
practices remains essential.
4.3. The Owner’s Opinion on the Use of Preservatives in Commercial Pet Food
The results from the Likert scale questions yielded important information on the
owners’ attitude to additives: the inclusion of such substances in pet food was deemed
unnecessary and even unhealthy by the majority of the respondents, particularly the older
age brackets. This was probably due to the perceived lack of “naturalness” of preservatives,
which were identified as predominantly synthetic by the majority of the sample. Such
results are in line with those from surveys on the use of preservatives in food intended
for human consumption, which show that consumers have little trust in artificial food
additives [
34
,
35
]. However, Shim et al. [
36
] showed that the consumer’s awareness and
knowledge of the use of preservatives greatly influence the safety perceived: whenever
appropriate information was provided, the percentage of people who expressed a positive
opinion of them more than doubled. Pet food manufacturers should therefore aim at
providing owners with targeted information on the usefulness and safety of additives in
order for them to develop conscious knowledge of the question. Veterinarians should
also help consumers build a solid and correct opinion on the use of preservatives in
pet food. This survey also showed that veterinarians were not the owners’ preferred
source of information on pet feeding, however, and that neither did they regularly seek
a veterinarian’s advice on the type of diet and the feeding quantity for their pet. Internet
has become a very popular tool, not only for purchasing pet food, used for the purpose
by a quarter of the interviewees, but also for acquiring information: almost one in five
participants relied on the web for the choice of the dry diet, and almost one in three for
the wet diet.
4.4. Home-Cooked and Raw Meat-Based Diets
The study suggests that Italian owners chose to feed their pets a HCD mainly due to
their distrust of commercial food or to better deal with the pathological conditions of their
pets. Surveys conducted previously have reported the same two main reasons for choosing
this type of diet [
18
,
37
]. The same reasons were also stated by RMBD-feeders, even if their
very first motivation was the belief that raw food is more biologically-appropriate for dogs
and cats, and this result confirms that of a previous study carried out in Italy [
38
]. The
abovementioned scarce appreciation of additives may be blamed as one of the reasons that
eventually leads to the lack of trust in industrial pet food and to the demand for alternative
“more natural” diets [39].
Fewer RMBD-feeders (i.e., one in two) than HCD-feeders (i.e., three in four) relied on
a professional figure for the formulation of their pets’ diets. The strong tendency of RMBDs
supporters to formulate pet diets by themselves, especially with support from internet and
books, instead of turning to a veterinarian or a nutrition-trained expert, has been disclosed
previously [
38
,
40
]. The frequency with which do-it-yourself recipes and ready-to-eat meals
are linked to an inadequate intake of many nutrients [
41
–
43
], such as minerals like calcium
and phosphorus and vitamins like vitamin D in RMBDs, above all [
44
] is well worth noting.
The need to consult a veterinary nutritionist when formulating a homemade diet in order
to avoid nutritional imbalances that can lead to serious long-term health consequences
should always be stressed [38,41–43].

Animals 2021,11, 273 15 of 19
Homemade diets were generally administered as two meals per day; the number of
owners who preferred to feed the animal a single daily meal was much higher among
RMBD-feeders (i.e., three times the HCD-feeders) however, probably due to the fact that
less frequent and larger meals resemble the natural eating behavior of the dog’s ancestors.
Only a small percentage of respondents reported always using fresh ingredients for
the preparation of their pets’ diets, while freezing was the most common method of meat
preservation. When frozen, meat was preserved for only a very short time before use, as is
usually the case of meat for human consumption [
45
]: the vast majority did not leave the
meat in the freezer for more than three months, a limit that meets the guidelines regardless
of type of meat [
46
]. Many owners reported defrosting meat at room temperature, whereas
a temperature between 5
◦
C and 7
◦
C is considered optimal for safe thawing, and higher
temperatures have been proven to promote faster bacterial growth [
46
]. Moreover, some
studies revealed that operational temperatures in domestic refrigerators are often higher
than 5
◦
C and sometimes even 10
◦
C, which may lead to faster food degradation and
bacterial growth [
45
,
47
]. Therefore, as demonstrated elsewhere [
48
], storing pet food in
the refrigerator or freezer may still pose some concerns, especially with RMBDs, whose
ingredients are administered uncooked regardless of thawing method.
Managing a RMBD involves major microbiological risks linked to handling raw meat,
which is often contaminated by pathogenic bacteria, some of which with zoonotic po-
tential [
49
]. If not managed properly, RMBDs can pose threats to animal and human
health. Bacterial foodborne illness in pets and related human infections have already
been reported [
50
–
52
]. However, many owners seem to underestimate the microbio-
logical risk posed by RMBD preparation [
38
] and this survey showed that few respon-
dents followed safe food handling recommendations, like working on dedicated surfaces
(i.e., one in four) or wearing gloves (i.e., less than one in three); a recent worldwide
internet-based survey involving more than 16 thousand respondents reported a similar
result, namely that the majority of the RMBD-feeders interviewed used the same place
and utensils regardless of whether the raw meat was intended for their pets or their own
consumption [
50
]. Moreover, almost half of the interviewed RMBD-feeders regularly
bought frozen ingredients online, and a recent study proved that these products may be
already highly contaminated at delivery and spoil very rapidly, especially if not kept at
lower refrigeration temperatures [
48
]. Given the higher risk rate, owners who choose to
feed RMBDs should take the appropriate precautions to protect human and animal health
both when handling and storing meat. It is also essential that veterinarians inform pet
owners and retail employees of the hazards of feeding and handling raw food [52].
4.5. Use and Storage of Fish Oils and Vegetable Oils
The HCD and RMBD formulations investigated often included fish oils and vegetable
oils. These products are at great risk of deterioration during storage due to their high
content of polyunsaturated fatty acids omega-6 and omega-3 [
53
]. Especially fish oils are
notably susceptible to spoilage because their oxidation rate is significantly higher than
that of other oils [
54
], and increasing storage temperatures has been shown to significantly
accelerate the oxidation process [
55
]. However, more than one in three respondents kept
fish oils at room temperature and such percentage did not vary much between those who
relied on a veterinarian and those who formulated the diet themselves. The proper storage
of oils should not be overlooked and, when prescribing the diet, the veterinarian should
always make sure the owner gets the right instructions in order to preserve the pet’s health
and appetite. Especially in summer, fish oils should be stored in the refrigerator at +4
◦
C
and their consumption is considered acceptable up to 90 days of opening the bottle [
55
].
Vegetable oils rich in PUFAs should also be stored at low temperatures in order to slow
down the oxidation process [56].

Animals 2021,11, 273 16 of 19
4.6. Management of Leftovers
Lastly, a substantial difference emerged among the four types of diet regarding the
management of leftovers. The dry diet was the one with the lowest rate of food waste,
probably thanks to the slower perishability of the product. Among the alternative diets,
owners who fed RMBDs were more attentive to this aspect than those who feed HCDs:
this could be due to the fact that a raw meat-based meal is on average more expensive than
a home-cooked meal because it contains more amounts of expensive foods (like meat and
fish) and fewer amounts of cheaper foods (like rice, pasta or other sources of carbohydrates).
Consequently, owners may be more reluctant to throw the raw meat leftovers in the trash
and prefer to keep them refrigerated until the next meal. More conscientious management
of leftovers by dog and cat owners may be the merit of growing global awareness and
commitment to the fight against food waste: given the large amount of meat products
included in home-prepared diets for pets, this kind of waste and its environmental impact
cannot be deemed negligible [57].
4.7. Limits of the Study
Certain limitations in this study should be considered in order to better interpret its
results. First of all, the limit imposed by language made the sample representative only
of Italian pet owners. Secondly, the survey was shared only on one social media and the
respondents were self-selected, so there may have been a sampling bias (e.g., age). Given
the length of the survey, it is possible that only the most conscientious owners took the time
to fill it out, and these people may be more concerned with storage issues than average. In
order to gain more comprehensive knowledge on the subject, additional studies should
investigate the storage practices of owners in different countries. It might also be useful to
examine the peculiarity of every single diet (i.e., commercial, HCDs, RMBDs) in greater
detail with ad hoc questionnaires. Finally, laboratory tests should be conducted to verify
the microbiological and chemical risks of pet food under different storage conditions.
5. Conclusions
In conclusion, kibble was the most common pet food adopted by the dog and cat
owners involved in this study. Wide participation in the survey permitted the acquisition
of evidence that the pet’s age affects the choice of diet in both species, whereas the owner’s
age plays a role in the choice of the diet for dogs but not for cats.
Bearing this in mind, the survey also demonstrated that owners care about pet food
preservation, and this was reflected in overall their good storage management despite the
wide variability of practices and type of diet. Some critical issues emerged nonetheless,
such as the possibility that dry pet foods and oils may be unintentionally exposed to
high temperatures, in this way definitely increasing their risk of going rancid. The most
delicate aspects regarding pet food storage should not be overlooked by veterinarians
when questioned about proper diet management by pet owners regardless of the type
adopted. Veterinarians should also provide precise instructions on storing highly perishable
ingredients (e.g., fish oil) to those who formulate home-prepared diets.
Finally, many people showed a strong dislike for the inclusion of preservatives in
commercial products, and this was especially evident for those in the older age brackets.
Manufacturers should adopt more explicative labelling and advertising that emphasizes
the importance of additives.
Supplementary Materials:
The following are available online at https://www.mdpi.com/2076-261
5/11/2/273/s1, File S1: original survey (English translation).
Author Contributions:
Conceptualization, G.M. and R.R.; methodology, G.M., D.S. and R.R.; valida-
tion, G.M. and R.R.; formal analysis, G.M., D.S. and R.R.; investigation, G.M. and D.S.; data curation,
G.M., D.S. and R.R.; writing—original draft preparation, G.M. and D.S; writing—review and editing,
G.M., D.S. and R.R.; supervision, R.R. All authors have read and agreed to the published version of
the manuscript.

Animals 2021,11, 273 17 of 19
Funding: This research received no external funding.
Informed Consent Statement:
No ethics approval either within national or EU legal systems was
needed for such procedure as enrollment was on a voluntary basis and the participants consented
to anonymous information collection as per General Data Protection Regulation (Regulation (EU)
2018/679). Interviewees agreed to participate in the study voluntarily by self-enrolling. They were
informed that their answers would be published in a study. By completing and returning the survey,
they agreed to the inclusion of their data.
Data Availability Statement:
The data presented in this study are available on request from the
corresponding author. The data are not publicly available due to privacy reasons.
Acknowledgments:
The authors would like to thank Barbara Contiero (Department of Animal Medicine,
Production and Health; University of Padua) for the technical support in the statistical analysis.
Conflicts of Interest: The authors declare no conflict of interest.
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