Blackened deposits inside the pottery shards - which are at least 6,100 years old - have been found to contain residues of microscopic plant silica bodies, called phytoliths, which resemble those found in modern-day garlic mustard seeds, a peppery mustard-flavoured spice.
Given that garlic mustard has little nutritional value, and the shards also contained residues of fats from a range of marine and terrestrial animals, as well as starchy plant foods, experts now believe that the early hunter-gatherer humans used the spice to flavour foods.
Led by Hayley Saul and colleagues from the University of York, the researchers present their findings from the pottery found in Denmark and Germany in PLoS One.
"Until now it has been widely accepted that the calorific content of foods was of primary importance in the decisions by hunter-gatherers about what to eat," said Saul. "Both the actual finding of seed phytoliths consistent with garlic mustard spice, and the method of discovery, open up a new avenue for the investigation of prehistoric cuisines."
The team said although garlic mustard was present locally, it is unclear whether the practice of using it as a spice originated in the western Baltic area or was derived from the Near East and brought to the region.
Regardless of the origins of the practice, the study concludes that the team have now established that the habit of enhancing and altering the flavour of calorie rich staples was part of European cuisine as far back as the 7th millennium BC.