Traditional and modern Nordic fermented milk products: A review

Fermented milk products have been an important contribution to the Nordic diet and food culture for thousands of years. They have transitioned from homestead-made, spontaneously fermented products to the mass-produced, standardised and safe products that we know today. With one notable exception (skyr), all past and present Nordic fermented milk products are characterised by fermentation by mesophilic lactic acid bacteria. The starter cultures are dominated by Lactococcus lactis subspecies, with a small percentage of leuconostocs and occasionally yeasts and moulds. The property characteristics of the various Nordic products are determined by the metabolism of these microorganisms and the technology used for their manufacture. This review describes the origin of the Nordic products, their present-day counterparts and the microbiology of their fermentation.