Donkey milk research · Study 164

Where does the milk come from? Tracing Italian donkey milk by its anions

Using five inorganic anions, the researchers assigned 45 donkey milk samples from three Italian regions to their origin – correctly in 91 to 98 % of cases. Phosphate (569.4 to 1304.4 mg/kg) and chloride (545.9 to 1757.9 mg/kg) were the most abundant anions.

Important: An analytical method for checking origin. It says nothing about quality, safety or effects of the milk, and the classification applies only to the three regions studied.

At a glance · swipe or use the arrows

The key figures

45donkey milk samples from Italy

3regions of origin as groups

5anions: chloride, nitrite, nitrate, phosphate, sulphate

569–1304mg/kg phosphate (569.4 to 1304.4)

546–1758mg/kg chloride (545.9 to 1757.9)

110–201mg/kg sulphate (109.5 to 200.7)

5.6mg/kg nitrite according to the abstract

5.5mg/kg nitrate according to the abstract

p < 0.001difference in chloride and nitrite between farms

91–98 %samples correctly assigned

Study design

How it was studied

Analytical study by the University of Messina (Italy): 45 donkey milk samples from different Italian regions were analysed for chloride, nitrite, nitrate, phosphate and sulphate by ion exchange chromatography with conductivity detection and chemical suppression. The data were divided into three groups by region of origin and compared by analysis of variance (ANOVA). Classification used a discriminant analysis of log-transformed concentrations and, alternatively, a three-step procedure. Based on the abstract; full-text details such as the names of the regions, number of farms and samples per region and the validation are therefore missing.

Laboratory study

Study typeMilk analysis (origin testing)CountryItalyYear2012JournalFood Addit Contam Part A Chem Anal Control Expo Risk Assess

Results

What the study measured

Phosphate (569.4 to 1304.4 mg/kg) and chloride (545.9 to 1757.9 mg/kg) were the most abundant anions, followed by sulphate (109.5 to 200.7 mg/kg).

For nitrite and nitrate the abstract gives much lower values of 5.6 and 5.5 mg/kg respectively; it does not state whether these are means or maxima.

Chloride and nitrite differed significantly between farms (p < 0.001).

A discriminant analysis based on the log-transformed anion contents and an alternative three-step procedure were tested.

Overall, 91 to 98 % of samples were assigned to the correct region on the basis of their anion content.

Authors’ conclusion: According to the authors, the procedure is simple and could serve to trace donkey milk and protect it against fraud or commercial disputes. This was shown for 45 samples from three regions – the paper does not show whether the classification works for other regions, seasons or feeding.

Critical appraisal

Strengths and limitations

Only the abstract assessedClear limitation

The full text was not available. Which regions, how many farms and how many samples per region were included is unknown.

Small data set, three regionsClear limitation

45 samples from three regions are a narrow basis. A model developed and tested on the same data may turn out too optimistic.

Region or farm?Note

The abstract reports differences “among farms”. Whether the patterns reflect the region or rather the feed, water and husbandry of individual farms remains open.

Unclear nitrite and nitrate figuresNote

Only single values without a range are given for nitrite and nitrate; their meaning is not clear from the abstract.

Simple, widely used techniqueStrength

Ion chromatography is available in many food laboratories. This makes the approach practical in principle for origin checks.

clear limitationnotestrength

Editorial note: The paper shows that donkey milk from three Italian regions could be distinguished well by its anion pattern. Reliable origin testing in trade would need larger sample numbers, several years and validation on independent samples. To the research archive.

Research question for DON DONKEY’S®

Can an anion or mineral profile be created for the donkey milk of each of our EU partner farms, making the origin of individual batches verifiable?

Milk analysisOriginTraceability

Original publication

Classification of the geographical origin of Italian donkey's milk based on differences in inorganic anions.

Original title: Classification of the geographical origin of Italian donkey's milk based on differences in inorganic anions.

Di Bella G., Lo Turco V., Potortì A. G., Luppino R. R., Fotia V., Conte F., Dugo G.
Food Additives and Contaminants: Part A · 2012 · 29(7), 1021–1029

Department of Food and Environment Sciences, University of Messina, Italy (according to author details)

DOI: 10.1080/19440049.2012.674979

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.

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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.

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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.