Posted on 10/03/2025 11:46:10 AM PDT by Red Badger
Red wood ants (Formica rufa) pheromone transmission. (Photo by Yuriy Bartenev on Shutterstock)
In A Nutshell
* Red wood ants carry Fructilactobacillus sanfranciscensis, the sourdough bacterium that can seed milk and trigger yogurt-like fermentation.
* In lab conditions, four live ants added to warm milk led to curdling by morning at about pH 5 (store yogurt is ~4.2), with mild tang and grassy notes.
* Ants contribute formic acid (about 1–2.5 g/L measured in the yogurt), lowering pH; ant-borne bacteria then make lactic and acetic acids and enzymes that cut milk proteins.
* Only live ants yielded stable, desirable communities; frozen or dehydrated ants favored hardy Bacillus spores and inconsistent results.
* Ethnographic accounts from Turkey and Bulgaria describe ant-started yogurt; chefs have explored controlled, restaurant-grade uses under safety protocols.
* Do not try this at home: potential parasite risks, EU “novel food” rules, and conservation concerns apply. A safer path is isolating the microbes and using them without live insects.
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COPENHAGEN — Red wood ants carry the same bacteria that makes San Francisco sourdough bread. Now scientists have rediscovered how villagers in Turkey and Bulgaria once used these insects to ferment yogurt.
Researchers from the University of Copenhagen and Denmark’s Technical University investigated a traditional food practice where live ants transform milk into tangy yogurt overnight. Their findings reveal that Formica ants host thriving colonies of lactic acid bacteria in their bodies, including Fructilactobacillus sanfranciscensis, the microbe famous for giving sourdough its distinctive sour flavor.
When the team analyzed yogurt made with these ants under sterile laboratory conditions, they found the insects transferred their bacterial passengers directly into the milk, where the microbes multiplied and fermented the dairy. Lead author Veronica Sinotte and colleagues published their results in iScience.
The discovery bridges an unexpected gap between two beloved fermented foods. While F. sanfranciscensis typically breaks down flour sugars in bread starter, the ant-associated strain showed it could adapt to a dairy environment, though it struggled with lactose, milk’s main sugar. The bacteria instead fed on simpler sugars and proteins in the milk, creating a slower fermentation than commercial yogurt cultures.
Red Wood Ant -(Formica rufa) from Euroasian forests and woodlands, Zlin, Czech Republic. (© David – stock.adobe.com)
Ants and Yogurt: Reviving a Forgotten Tradition
The research team traveled to a Bulgarian village where elderly residents remembered burying jars of milk inside ant colonies. Ethnographer Sevgi Mutlu Sirakova, who grew up hearing stories about ant yogurt, guided the scientists to a red wood ant mound where locals still practiced the tradition each spring.
Four live ants went into a jar of warm raw milk. The jar, covered with cheesecloth, sat inside the heated ant nest overnight. By morning, the milk had curdled and acidified to a mildly acidic pH of 5 (less sour than store-bought yogurt at 4.2), with what chef David Zilber described as “a slight tangy taste with mild herbaceousness and pronounced flavors of grass-fed fat.”
Similar practices existed across Turkey and the Balkan Peninsula. A 1977 account by ethnographer Ali Rıza Yalman described Turkish nomads crushing ant eggs to start yogurt when they lacked conventional starter cultures. The tradition faded as industrial yogurt production took over, but these communities preserved knowledge of a remarkable biological partnership.
Following a traditional Bulgarian method of yogurt-making, researchers added four live forest ants into a warm jar of milk. (Credit: David Zilber)
How Ants and Bacteria Team Up
The study examined what scientists call the ant “holobiont,” the insect plus its microbes working together as one system. Formica ants produce formic acid in their venom glands. When added to milk, this acid immediately began lowering the pH. The researchers measured formic acid at 1-2.5 grams per liter in the yogurt, creating ideal conditions for their bacterial partners.
The bacteria then took over, producing lactic and acetic acids that further acidified and thickened the yogurt. The team also detected enzymes from both ants and bacteria that could break down casein, milk’s main protein, potentially contributing to the yogurt’s texture.
When researchers compared yogurts made with live, frozen, or dehydrated ants, only the live versions produced consistent, desirable bacterial communities. Frozen and dehydrated ants allowed spore-forming Bacillus bacteria to dominate instead, including potential food contaminants. The temperature changes appeared to kill beneficial bacteria while Bacillus spores survived.
Live ant yogurts maintained remarkably stable bacterial communities across different batches, containing primarily lactic and acetic acid bacteria. The microbiome stayed consistent between spring and autumn collections, though bacterial populations in the ants themselves shifted seasonally.
Two-Star Restaurant Takes Notice
The findings caught the attention of Alchemist, a Copenhagen restaurant ranked eighth-best in the world and holding two Michelin stars. The research and development team created three dishes using ant-fermented dairy.
Their “ant-wich” features ice cream made from sheep yogurt fermented with live ants, sandwiched between ant-infused gel and tuile cookies shaped like an ant. A mascarpone-style cheese uses dehydrated ants instead of citrus to curdle goat milk and cream, producing a pungent flavor resembling aged pecorino. A milk-wash cocktail replaces traditional citrus acid with ant-derived formic acid, creating a silky aperitif with fruity notes.
The culinary applications required careful food safety measures. Live ants were strained through 100-micron filters to remove potential parasites, though these occur at low prevalence. Freezing also kills parasites, but the research showed frozen ants produced inferior fermentation results.
Sample collected from ant yogurt fieldwork in Bulgaria, including yogurt and local forest ants. (Credit: David Zilber)
What Industrial Yogurt Left Behind
The research highlights how industrial food production has narrowed the microbial diversity once central to traditional fermentation. Commercial yogurt relies almost exclusively on two bacterial species: Lactobacillus delbrueckii subsp. bulgaricus and Streptococcus thermophilus. Bulgarian microbiologist Stamen Grigorov isolated these bacteria in the early 1900s, launching industrial yogurt production that displaced diverse traditional cultures.
Traditional yogurts, by contrast, hosted multiple bacterial species and strains that varied by region, reflecting local animals, environments, and practices. Turkish mountain villages, for example, used pinecones to introduce key microbes into milk. Other communities employed chamomile flowers, linden flowers, nettle roots, or leaves from various plants.
The study’s bacterial surveys revealed that Formica ants across Europe and North America consistently host lactic acid bacteria, particularly Fructilactobacillus species. These bacteria appear to have diversified alongside the ants over millions of years. The researchers suggest ants may serve as reservoirs for fermentation microbes, potentially useful for modern food production.
F. sanfranciscensis isolated from the ant yogurt could metabolize ten different types of sugars, including glucose, fructose, and ribose. Sourdough strains typically use maltose and sucrose, while the ant strain showed different metabolic capabilities, likely adapted to the ant environment where it feeds on honeydew and insect proteins.
Not for Home Experimentation
The researchers caution against attempting ant yogurt without expertise in food microbiology or cultural ties to the practice. Formica ants can carry Dicrocoelium dendriticum, a parasite affecting humans, though prevalence remains low. Traditional practitioners may have developed safety measures passed down through generations, such as not crushing the ants or using specific fermentation conditions.
European Union regulations classify Formica ants as novel foods not approved for sale, despite documented traditional use. This regulatory status creates tension between preserving culinary heritage and modern food safety frameworks.
The practice also raises conservation concerns. Several red wood ant species have experienced population declines across Europe, making large-scale collection unsustainable. The scientists collected ants carefully without disturbing nest structures and suggest isolating the bacteria for use independently of live insects.
Where Do Fermentation Microbes Come From?
The findings open questions about where fermentation microbes originally came from. Recent research showed social wasps carry wine yeasts, suggesting insects may have served as ancient vectors for fermentation cultures. The ant-sourdough connection raises similar possibilities for bread.
Breadmaking dates to at least 14,400 years ago in Jordan, while the earliest yogurt evidence comes from 7,000-year-old ceramic residues in Turkey. Ants have existed in these regions far longer. Whether ancient peoples deliberately used insects to inoculate ferments, or whether microbes jumped from insects to food by chance, remains unknown.
Sinotte emphasizes that the research aims to document and understand traditional practices rather than commercialize them. The bacteria isolated from ant yogurt could potentially be cultured independently for use in dairy or plant-based fermentation, preserving the microbial heritage without requiring live insects.
The partnership between ants and bacteria offers lessons about food fermentation as a multispecies collaboration. Conventional yogurt production views bacteria as tools to be controlled. The ant holobiont reveals fermentation as an ecological process where different organisms contribute complementary functions: acids from ants, sugars metabolized by bacteria, enzymes from both, collectively transforming milk into something new.
Disclaimer: This article is for general information only. It is not advice on food preparation or safety.
Paper Summary
Methodology
Researchers collected red wood ants (Formica polyctena and F. rufa) from colonies in Denmark and Bulgaria during spring and autumn. They characterized ant microbiomes using 16S rRNA gene sequencing and isolated bacteria through culture methods on various growth media. Experimental yogurts were prepared under sterile laboratory conditions using reconstituted milk powder and three ant preparations: live ants, frozen ants, or dehydrated ants. Yogurts fermented at 42°C for eight hours, then were analyzed for bacterial communities (via DNA sequencing), organic acids (via high-performance liquid chromatography), bacterial abundance (via quantitative PCR), and enzymes (via proteomics). Traditional yogurt preparation was documented through fieldwork in Bulgaria, and modern culinary applications were developed with Alchemist restaurant in Copenhagen.
Results
Live ant yogurts contained consistent bacterial communities dominated by lactic acid bacteria (primarily Fructilactobacillus sanfranciscensis) and acetic acid bacteria. These bacteria from the ants proliferated in milk during fermentation. Frozen and dehydrated ant yogurts showed variable, less desirable bacterial communities including potential food contaminants like Bacillus species. The ant holobiont contributed three key components to fermentation: formic acid from the ants themselves (1-2.5 g/L), lactic and acetic acids from bacteria (lower than conventional yogurt), and proteases from both ants and bacteria with potential casein-degrading activity. Ant microbiomes showed seasonal variation, with higher bacterial loads in autumn, but resulting yogurt microbiomes remained stable across seasons. The isolated F. sanfranciscensis strain metabolized ten carbohydrate substrates but lacked lactose metabolism, distinguishing it from conventional yogurt bacteria. Experimental yogurts remained at pH 5.0-5.9, less acidic than commercial yogurt’s pH 4.2.
Limitations
The study examined one F. polyctena colony for experimental yogurts, which may not represent natural colony-to-colony variation. Fermentation conditions were not optimized, so yogurts did not reach the acidity or bacterial biomass of commercial yogurts, remaining at pH 5.0-5.9 rather than 4.2. The research could not definitively determine whether F. rufa and F. polyctena perform identically in fermentation. Food safety risks were not fully characterized, particularly regarding potential pathogen loads in frozen/dehydrated preparations. The study focused on bacterial communities and did not examine yeasts or other microorganisms that might contribute to traditional fermentations. Seasonal microbiome data came from limited time points (late May/early October), potentially missing other seasonal variations.
Funding and Disclosures
The research was supported by the Danish National Research Foundation Center for Evolutionary Hologenomics (DNRF 143) and the Novo Nordisk Foundation (Grant NNF20CC0035580). Leonie J. Jahn is the founder of MATR Foods Aps. Rasmus Munk is the founder and owner of restaurant Alchemist and Spora Aps. Other authors declared no conflicts of interest.
Publication Information
Sinotte, V.M., Ramos-Viana, V., Prado Vásquez, D., Mutlu Sirakova, S., Rodríguez Valerón, N., Cuesta-Maté, A., Taylor Parkins, S.K., Giecko, J., Merino Velasco, E., Zilber, D., Munk, R., Andersen, S.B., Dunn, R.R., & Jahn, L.J. (2025).
“Making yogurt with the ant holobiont uncovers bacteria, acids, and enzymes for food fermentation,” published in iScience on October 3, 2025.
DOI: 10.1016/j.isci.2025.113595
They will make us eat ze bugs one vay or an udder..........
I don’t think so.
🤮
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Or dead ants, for that matter.
or uncles ...
There is no indication in the article that the ants take a shower before going for a swim in the milk. I’m uncomfortable with this.
lol. “Ant” i-perspirant .
Yogurt wasn’t already tangy enough?!
Effing disgusting. How much USAID money went to this “experiment”?
You vill eet zee bugz und like it!
They are better than maggots.
This is science we can do without.
I want my ant yogurt and I want it now.
The only way I’ve eaten ants is CHOCOLATE COVERED...on a DARE! ;)
a. WHERE do you find this sh#t to post? LOL!
b. “Only live ants yielded stable, desirable communities; frozen or dehydrated ants favored hardy Bacillus spores and inconsistent results.”
Wait! Does PETA know about this?!?!
c. Keep ‘em coming! :)
Wow again! I just thought about living on the farm and the four or five gallons of curdled milk in the churn that my siblings and I always had to take turns churning that putrid stuff. That might have affected my feelings about butter milk and yogurt.
Way ahead of ya, pal.
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