Donkey milk research · Study 175

Donkey milk under the sequencer: which bacteria it carries

All bacterial sequences from bulk milk of Italian donkey dairy farms could be assigned to five bacterial phyla. The six most frequent genera were Gram-negative, and lactic acid bacteria accounted on average for 2.55 % of sequences per sample. Composition varied between and within farms.

Important: A microbiological inventory. It measures shares of bacterial DNA, not bacterial counts, and says nothing about any effect in humans or about the safety of the milk.

At a glance · swipe or use the arrows

The key figures

5bacterial phyla in all samples

6most frequent genera, all Gram-negative

2.55 %share of lactic acid bacteria in sequences per sample

6genera of lactic acid bacteria, e.g. Lactococcus

2 yearssampling in consecutive years

Bulk milkfrom donkey dairy farms in Italy

Core taxacore microbiota: milk, soil, water and plant bacteria

variableshare of cocci and rods between farms

4authors, University of Turin

2017year of publication, Int J Food Microbiol

Study design

How it was studied

Milk analysis by a research group at the University of Turin (Italy): bulk milk samples from Italian donkey dairy farms collected in two consecutive years were analysed by high-throughput sequencing of bacterial DNA. Assignment to phyla and genera, the shared core microbiota and the share of lactic acid bacteria were evaluated. Assessed based on the abstract; the full text was not available to the editorial team. The number of farms and samples and the shares of individual genera are therefore not stated.

Laboratory study

Study typeMilk analysis (microbiology)CountryItalyYear2017JournalInt J Food Microbiol

Results

What the study measured

All sequences belonged to five bacterial phyla: Proteobacteria, Firmicutes, Bacteroidetes, Actinobacteria and Verrucomicrobia.

The most frequent genera were Pseudomonas, Ralstonia, Acinetobacter, Cupriavidus, Citrobacter and Sphingobacterium, all Gram-negative.

The core microbiota comprised typical milk bacteria, lactic acid bacteria and species normally found in soil, water and plants.

Sequences of the lactic acid bacteria Streptococcus, Lactococcus, Enterococcus, Leuconostoc, Lactobacillus and Carnobacterium accounted on average for 2.55 % of all sequences per sample.

The distribution of coccus- and rod-shaped lactic acid bacteria varied between and within farms.

Authors’ conclusion: According to the authors, the study is a snapshot of the bacterial community in donkey milk that shows its variability and prompts further research into the technological potential of naturally occurring bacteria. It provides no bacterial counts and no hygiene assessment of the milk.

Critical appraisal

Strengths and limitations

DNA, not bacterial countsClear limitation

Sequencing shows relative shares of bacterial DNA. Living and dead cells are not distinguished, and absolute amounts are not determined.

No safety assessmentNote

The aim was to describe the bacterial community. No statement on hygiene can be derived from genus names alone.

Only the abstract assessedNote

The number of farms and samples, sampling procedure and shares of individual genera are unknown without the full text.

Italian farms onlyNote

The bacterial community depends on husbandry, milking technique and environment. Other regions may differ.

Two years, several farmsStrength

Samples from two consecutive years and several farms make the natural variation of the bacterial community visible.

clear limitationnotestrength

Editorial note: The paper describes how diverse and variable the bacterial community in raw donkey milk is, including naturally occurring lactic acid bacteria. It is an inventory of milk microbiology, not a statement on safety or effects. To the research archive.

Research question for DON DONKEY’S®

How much does the bacterial community differ between batches from our partner farms and between seasons – and could such a profile be used for the origin transparency of a batch?

Milk analysisMicrobiologyLactic acid bacteria

Original publication

Characterization of bacterial communities of donkey milk by high-throughput sequencing.

Original title: Characterization of bacterial communities of donkey milk by high-throughput sequencing.

Soto Del Rio M. L. D., Dalmasso A., Civera T., Bottero M. T.
International Journal of Food Microbiology · 2017 · 251, 67–72

Department of Veterinary Sciences, University of Turin, Grugliasco, Italy (according to the authors)

DOI: 10.1016/j.ijfoodmicro.2017.03.023

Transparency: funding and conflicts of interest could not be checked from the abstract. No product-related statement for DON DONKEY’S®.

Summarised and checked by the DON DONKEY’S editorial team against the original publication · As of: November 2026

End of the study summary

Note on our products

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.

Transparency: The study examined milk from another herd – not the milk from our partner farms.

€24,90

100 ml bottle / 100ml · Unit price: €249,00 / 1 l · incl. VAT, plus shipping

View all sizes & purchase options →

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.

Transparency: The study did not examine our donkey milk powder.