Recent archaeological findings have uncovered the secret ingredient behind the popular Roman fish sauce, garum. Until now, garum’s distinctive flavor remained largely documented in texts, but a team of researchers has identified European sardines as the primary ingredient through ancient DNA analysis from a fish-salting vat at the Adro Vello site in northwestern Spain.

Published in Antiquity, this groundbreaking study relied on sophisticated techniques to extract and sequence genetic material from fish bones preserved in the dregs of garum production. Dr. Paula Campos, the lead author of the study from CIIMAR at the University of Porto, noted that the conditions within fermentation vats were typically hostile to DNA preservation.

However, the research demonstrated that workable DNA can survive despite these harsh conditions. The study marks a crucial breakthrough, as it represents the first successful identification of fish species from degraded genetic material.

Using advanced sequencing methods, the researchers aligned DNA fragments from the ancient fish bones with contemporary genomes, confirming the specimen as *Sardina pilchardus*, the European sardine. This method could enhance the understanding of regional variations in the main ingredients used in ancient fish sauces.

Garum was widely consumed throughout the Roman Empire, serving as a versatile seasoning. Its production was industrialized, particularly in Hispania and North Africa, where extensive fish-salting factories, or cetariae, emerged.

The findings from Adro Vello, a well-preserved fish-salting plant, reveal the extensive role of garum in the culinary landscape of ancient Rome. In addition to culinary insights, this research opens avenues in marine biology, indicating that ancient sardines had genetic similarities to modern populations.

As the team broadens its investigation to other production areas, they aim to glean further insights into trade routes and regional economies, potentially reshaping our understanding of ancient supply chains and ecosystem changes over time.