Assessment of donkey milk chemical, microbiological
and sensory attributes in Greece and Cyprus
ELENI MALISSIOVA, 1
* GEORGIOS ARSENOS, 2 PHOTIS
PAPADEMAS, 3 DIMITRIOS FLETOURIS, 2 ATHANASIOS MANOURAS, 1
MARIA ASPRI, 3 AIKATERINI NIKOLOPOULOU, 1 ALEXANDRA
GIANNOPOULOU1 and IOANN IS S ARVAN ITOYANN IS4
1
Dairy Laboratory, Faculty of Food Technology, Technological Educational Institute of Thessaly, 43100 Karditsa,
2
Faculty of Veterinary Medicine, School of Health Sciences, Aristotle University of Thessaloniki, 54124, Thessaloniki,
Greece, 3
Department of Agricultural Sciences, Biotechnology and Food Science, Cyprus University of Technology,
3603 Lemesos, Cyprus, and 4
School of Agricultural Sciences, University of Thessaly, Fytokou Str., Nea Ionia
Magnessias, 38446 Volos, Greece
This study aimed to assess the nutritional, hygienic and sensory characteristics of donkey milk produced
in Greece and Cyprus. The average values for pH, fat, protein and lactose were 7.14,
0.52 g/100 mL, 1.22 g/100 mL and 7.01 g/100 mL, respectively, whereas aflatoxin M1 and betalactam
residues were not detected in any sample. The microbiological analysis revealed very low
somatic cell counts and total microbial counts, while Escherichia coli, Salmonella spp and Listeria
monocytogenes were not detected in any sample. The sensory evaluation classified the milk as
white, thin, with a slightly sweet pleasant taste, pleasant milky aroma, sweet flavour and no persistent
aftertaste.
Keywords Donkey milk, Milk composition, Hygiene, Greece, Cyprus.
INTRODUCTION
Donkey milk (DM) use dates back to antiquity
with numerous references for its virtues by
Greek and Roman historians. Over the last decade,
research has been directed towards the
properties and uses of DM that has a distinct
chemical composition and consequently particular
nutritional properties, similar to breast milk
(Guo et al. 2007;). In Greece and Cyprus, there
are ethnographic reports about using donkey’s
milk (DM) to feed infants either as a replacement
of breast milk or as a means to treat specific
illness, that is whooping cough. The notion
is that the latter was due to the composition and
the biological activity of DM; such assumption
has only recently been partly justified (Tidona
et al. 2011).
The status of donkeys in Greece was recently
investigated by Arsenos et al. (2010). They
reported an increased interest in donkeys in
Greece due to their potential for milk production.
Based on the latest census, donkeys’
population in Greece and Cyprus was 16 443
and 2000. In both countries, there is enhanced
interest from consumers for DM, while there are
no official reports or published data with reference
to its quality and hygiene.
The evidence in the literature suggests that
DM contains less fat, less protein but more lactose,
when compared to cow’s milk, and therefore,
it is easily digestible, palatable and rich in
nutrients (Salimei and Fantuz 2012). More specifically,
the available research data summarise
DM composition as follows: 8–10 g/100 mL
total solids, 1.5–1.8 g/100 mL protein, 6–7 g/
100 mL lactose and 0.28–1.82 g/100 mL fat
(Salimei et al. 2004; Piccione et al. 2008; Tidona
et al. 2011). Moreover, DM has been classi-
fied as hypoallergenic (Monti et al. 2007;
Restani et al. 2009; Bertino et al. 2010) and
also rich in natural antimicrobials (Zhang et al.
2008). The latter has been erroneously interpreted
by some raw DM consumers, constituting
an alerting issue for both scientists and consumers
(Zhang et al. 2008). The microbiological
*Author for
correspondence. E-mail:
malissiova@teilar.gr
© 2015 Society of
Dairy Technology
Vol 68 International Journal of Dairy Technology 1
doi: 10.1111/1471-0307.12245
status of DM is characterised by very low microbial load,
which is attributed to the antimicrobial activity of lysozyme
(Zhang et al. 2008). The lack of comprehensive evidence
regarding the level of safety and the nutritional value of
DM in Greece and Cyprus, as well as its potential uses,
have been the main drivers for this study. Hence, the objective
was to study the chemical, microbiological and sensory
attributes of DM produced in Greece and Cyprus.
MATERIALS AND METHODS
Sample collection
A total of 90 DM samples (79 from 6 Greek farms and 11
from a Cypriot farm) were randomly collected. All animals
used to obtain milk samples belonged to the indigenous
Greek Donkey and Cypriot Donkey breeds, respectively. All
donkeys selected for sampling were thoroughly examined
for any signs of clinical disease, and there was no medication
administered.
Compositional analysis
All milk samples were analysed by applying the ISO
2446:2008 for the determination of fat, using the CH-8307
Gerber centrifuge (Gerber Instruments AG, Effretikon, Switzerland),
ISO 8968-2:2001 for total nitrogen, using the Kjeltec
8100 (FOSS Analytical A/S, Hillerod, Denmark), and
the AOAC 984.15-1985 for lactose, using a UV–vis spectrophotometer
DR 5000 (Hach Lange, D€usseldorf,
Germany), while pH was measured with the Hanna Instruments
pH210 (Woonsocket, RI, USA).
Chemical contaminants determination
Thirty samples were tested for aflatoxin M1 (BIOOScientific
Corp.-1060-01) and beta-lactam (BIOOScientific Corp.-
1065-1) residues by ELISA (ASYS EXPERT 96; Biochrom
Ltd, Cambridge, UK), strictly following the kit’s instructions.
Microbiological analysis
A total of forty-one samples were analysed by applying the
ISO 4833:2003 for total viable count (TVC) enumeration,
ISO 6611:2004 for yeasts and moulds, ISO 15214:1198 for
lactic acid bacteria, ISO 21528-2:2004 for Enterobacteriaceae,
ISO 11866-1:2005 for Escherichia coli, ISO 6888-
1:1999 for Staphylococcus aureus, ISO 11290-1-1996 for
Listeria monocytogenes and ISO 6579:2002 for Salmonella
spp. Somatic cells counts were also determined by microscopic
enumeration (ISO 13366-1) using the XSZ-107BN
Binocular Microscope (Jiangsu Zhengji Instruments, Jin
Tan, China).
Sensory analysis
Thirty pasteurised samples were submitted for sensory evaluation
by ten panellists (four females and six males, aged
22–45 years). The panellists were selected according to ISO
8586-1. Samples were described using quantitative descriptive
analysis. The sensory evaluation tests were performed
in individual booths with controlled temperature and lighting
conditions. The panellists received approximately
10 mL of each sample at temperatures between 7 and 8 °C
in disposable plastic cups, coded from 1 to 30, respectively.
Water was available to panellists during the test. On a standardised
sensory test form (with a 5-point hedonic scale),
panellists presented the perceived intensities of each of the
attributes checked, namely appearance, taste, aroma, flavour,
aftertaste and texture. Reference standards were used to
develop the appropriate descriptive abilities of the panel and
to also calibrate the panellists in using the intensity scale, as
described in Chapman et al. (2001).
Statistical analysis
Data were analysed using the statistical package SPSS 15.0
(SPSS Inc, Chicago, Illinois, USA). Quantitative data are
presented as mean with standard deviation (SD). Kruskal–
Wallis test was used to examine differences between categories
of qualitative variables and quantitative variables.
Results were considered statistically significant when the P
was <0.05.
RESULTS AND DISCUSSION
Chemical composition and residues
The chemical composition of DM is presented in Table 1,
and results are in line with other studies (Guo et al. 2007;
Medhammar et al. 2011; Salimei and Fantuz 2012). It is
confirmed that DM composition is similar to human milk
and could be used for a variety of purposes (Vita et al.
2007; Tesse et al. 2009). However, any suggestion to use
DM as alternative milk for infants should take into consideration
its low fat content. When sample’s results from the
different areas were compared, there were statistically significant
differences regarding pH (P < 0.001), protein
(P < 0.001) and fat (P = 0.005) (Table 2), which could be
attributed to the fact that the sampled population belonged
to different breeds and it was reared under different conditions.
There is evidence in the literature that DM is influenced
by the feeding regime, breed and age (Salimei 2011).
This study also assessed the presence of beta-lactam residues
and aflatoxin M1 and results showed that the milk
tested was clear. Beta-lactams have been selected to be
tested in this study, as they represent the most common
antibiotics applied in farming. Thus, there is no literature on
the pharmaceutical residues in DM. Passantino et al. (2011)
have reported, however, the challenges of ivermectin residues
in DM. With reference to aflatoxin M1, Caloni and
Cortinovis (2011) reported the occurrence of aflatoxins in
feeds for equines, while there is no report on aflatoxin M1
occurrence in DM. Aflatoxin M1 and antimicrobial residue testing should be evaluated when milk is intended for
human consumption.
Microbial flora
Microbiological analysis showed very low microbial counts
(Table 1), while Escherichia coli, Salmonella spp and Listeria
monocytogenes were not detected (Figure 1). Somatic
cells were found to be low (8.1 9 103 cells/mL). These
results are in agreement with other studies (Ivankovic et al.
2009; Pilla et al. 2010; Salimei 2011), implying the antimicrobial
capacity that is present in DM (Zhang et al. 2008;
Mao et al. 2009). Many consumers prefer raw DM because
they believe it maintains all the beneficial attributes, and thus, it is important to stress that several zoonotic agents
(e.g. Brucella) have not been yet investigated in depth in
DM. Hence, the Greek government recently announced a
decision (314/15074-FEK 363, 17/2/2014) that requires DM
sanitisation prior to consumption.
Sensory analysis
Panel members defined DM as white, thin, with a slight
sweet pleasant taste, pleasant milky aroma, sweet flavour
and no persistent aftertaste. The mean scores (Figure 2)
obtained for the sensory attributes were similar among the
assessed milk samples (P > 0.05). The sensory analysis
conducted in this study confirmed consumer’s perception
that DM is a tasty food, as it has a slight sweet taste due to
the high lactose content as reported by other researchers
(Salimei 2011; Gubic et al. 2014).
To the best of our knowledge, this is the first study in
Greece and Cyprus in relation to DM, which allows us to
make an initial assessment and to reflect the potential for
exploitation. Thus, there is need to systematically assess the
impact of feeding regime on milk’s quality and to investigate
in depth donkeys’ health profile.
CONCLUSION
The examined DM had similar composition to breast milk,
had extremely low microbial counts and highly acceptable
sensory characteristics scores. Given the interest of consumers
and farmers in Greece and Cyprus for DM production, it
seems that there are grounds for further research to investigate
any possible health and nutritional effects it may have.
REFERENCES
Assessment of donkey milk chemical,
microbiological and sensory attributes in
Greece and Cyprus , ARTICLE in INTERNATIONAL JOURNAL OF DAIRY TECHNOLOGY · AUGUST 2015
http://www.researchgate.net/publication/280874321_Assessment_of_donkey_milk_chemical_microbiological_and_sensory_attributes_in_Greece_and_Cyprus
