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Research on donkey milk · Study 2
Donkey milk at 9 and 15 degrees
In 2012, Šarić et al. inoculated raw milk from Serbian Balkan donkeys with E. coli and salmonella in the laboratory: at what temperature did the milk inhibit the bacteria most – and how did its natural microflora behave when chilled?
What it's about
How does donkey milk respond to bacteria?
The Balkan donkey, an old native breed, lives in the Zasavica nature reserve in Serbia. Researchers from the Institute of Food Technology at the University of Novi Sad examined the raw milk of these animals.
They deliberately inoculated the milk with E. coli or Salmonella Enteritidis and followed how the bacteria developed over four days at different temperatures. In a second experiment, they observed the natural microflora for six days at 4 °C.
They also determined the protein profile of the milk – especially the levels of lysozyme and lactoferrin.
What exactly was studied?
Briefly explained
The terms used in this study
A food is deliberately inoculated with certain bacteria. Then it is measured whether they grow, stay the same or decrease in it.
A common salmonella variant routinely used as a test organism in food microbiology.
A natural enzyme that can attack the cell wall of certain bacteria. Present in particularly large amounts in donkey milk.
An iron-binding milk protein to which research attributes antibacterial properties.
On three dates, the morning milk of 8 jennies was pooled and transported at 4 °C.
Samples were inoculated with E. coli or salmonella and observed for 96 hours.
Untreated milk was tested for its microflora for six days at 4 °C.
The protein profile including lysozyme and lactoferrin was determined.
Interactive · The data at a glance
Two experiments, five views
Where did the milk come from, how was the experiment run, which temperature showed the strongest effect – and what did chilled storage and protein analysis show? Switch between the views.
Untreated milk · 4 °C · day 6Natural microflora in the storage experiment
Illustration of the findings reported in the original publication. Layout and graphics are schematic; the temperature scale only shows the values given in the abstract.
Key findings
What the researchers report
Inhibition depends on temperature
The antibacterial activity was not constant: depending on the test organism, the most favourable test temperature was different.
In the samples: no pathogens detected after 6 days at 4 °C
Salmonella, E. coli, Clostridium perfringens, coagulase-positive staphylococci as well as yeasts and moulds were not detected after six days.
Much lysozyme, little lactoferrin
The researchers focused on these two proteins, to which research attributes antibacterial properties.
The effect of the whole milk was measured. The study does not show whether lysozyme and lactoferrin alone are responsible for the inhibition. "Not detected" does not mean sterile – the total bacterial count increased in the storage experiment.
Critical assessment
Antibacterial – but not across the board
What the study shows
What it does not show
Research question for DON DONKEY’S®
How does our milk behave in the laboratory?
The Serbian study is one of the early works on the antibacterial activity of whole donkey milk. The same research group investigated the topic further in 2023 with 137 samples (Study 5). For us it is a prompt to test our own milk using comparable methods.
Original publication
Antibacterial properties of Domestic Balkan donkeys’ milk
Šarić L. Ć., Šarić B. M., Mandić A. I., Torbica A. M., Tomić J. M., Cvetković D. D., Okanović Đ. G.
International Dairy Journal · 2012 · 25(2):142–146
Institute of Food Technology, University of Novi Sad · funded by the Serbian Ministry of Education and Science (project TR-31029)
DOI: 10.1016/j.idairyj.2012.03.007
Repository entry: University of Novi Sad
The publication describes the milk of a specific donkey herd in Serbia. It does not allow any product-related statement for DON DONKEY’S®.
From our shop
DON DONKEY’S® donkey milk
100 % donkey milk · raw milk, frozen
On this page we report the findings of a published study. Independently of that, you will find our donkey milk here: 100 % donkey milk, frozen as raw milk.
100 ml bottle / 100ml · Unit price: €249,00 / 1 l · incl. VAT, plus shipping
Also in our shop
Donkey Milk Powder
Donkey milk in powder form
For anyone who prefers a longer shelf life: our donkey milk in powder form – easy to store and portion.
20g · Unit price: €1.245,00 / 1 kg · incl. VAT, plus shipping