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Research on donkey milk · Study 46
Resistant bacteria in donkey milk – a laboratory experiment
In 2026, a Serbian team deliberately added ten bacteria from hospitals to raw and pasteurised donkey milk – including several multidrug-resistant strains. For eight hours they counted how much the bacteria multiplied, compared with cow’s milk and nutrient broth.
What it's about
How do difficult bacteria behave in donkey milk?
Bacteria against which many antibiotics no longer work are a major issue in hospitals. Donkey milk naturally contains proteins such as lysozyme and lactoferrin, which are studied in research in connection with bacteria.
The team from Novi Sad wanted to know whether gram-negative hospital isolates – including strains with known resistance enzymes – grow differently in donkey milk than in cow’s milk or nutrient broth. And whether it makes a difference if the donkey milk is raw or pasteurised.
What exactly was studied?
Briefly explained
Laboratory terms
A large group of bacteria with a double cell envelope, such as E. coli or Klebsiella.
Insensitive to agents from at least three groups of antibiotics.
Abbreviations for enzymes with which bacteria render certain antibiotics ineffective.
Bacterial count per millilitre on a base-ten scale: 2 log = 100, 6 log = 1 million.
One batch of donkey milk, divided into raw and gently pasteurised.
Each sample was inoculated with around 100 cells per millilitre of one isolate.
Eight hours at 37 °C – in parallel in cow’s milk and nutrient broth.
The bacterial count was determined every hour, all in three runs.
Interactive · The data at a glance
Ten bacteria, four liquids
Which samples were compared, which isolates were tested, how strong the clearest effect was, how differently the bacteria responded – and what pasteurisation changed. Switch between the views.
Values from the freely accessible original publication. For cow’s milk, the authors give no single final value for this isolate in the text, so it is missing from the bar view.
Key findings
What the researchers report
Less growth than in cow’s milk and nutrient broth
all 10 isolates · p < 0.001Across all isolates, the bacteria grew significantly more in nutrient broth and cow’s milk than in raw or pasteurised donkey milk. How large the difference was depended on the isolate.
Two multidrug-resistant strains barely multiplied
K. pneumoniae A4 · E. coli A1For a Klebsiella with OXA-48, the count in raw donkey milk remained below 2 log after eight hours – in nutrient broth it was above 6 log. The result was similarly clear for an E. coli with CTX-M.
Resistance did not predict the response
7 of 10 multidrug-resistantSome multidrug-resistant strains were strongly slowed, others kept growing – albeit more slowly than in nutrient broth. There were only very few isolates per resistance enzyme.
Components such as lysozyme or lactoferrin were not measured; the authors describe possible causes only from the literature. Differences from cow’s milk may also be due to protein, fat, sugar and minerals.
Critical assessment
A test tube is not a body
What the study shows
What it does not show
Research question for DON DONKEY’S®
What does this mean for how we handle milk?
For us, what matters most in this study is the practical side: how do microorganisms behave in donkey milk during storage and processing – and how do we safeguard the quality of our raw milk from collection to the customer?
Original publication
Growth-Inhibitory Activity of Raw and Pasteurized Donkey Milk Against Clinically Relevant Gram-Negative Isolates with Different Antimicrobial Resistance Profiles
Trudić A., Šarić L., Plavšić D., Todorić O., Pelić M., Čabarkapa I., Tomanić D.
Animals · 2026 · volume 16, issue 13, article 1996 · open access
DOI: 10.3390/ani16131996
A laboratory study with bacteria in the test tube – no product-related statement for DON DONKEY’S®.
The study summarised above was carried out independently of DON DONKEY’S® and does not relate to our products. It serves solely to inform about the state of research.
DON DONKEY’S® donkey milk and donkey milk powder are foods. They are not intended to prevent, treat or cure any disease and do not replace medical advice.
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
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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
View all sizes & purchase options →