Kefir: A milk beverage with a rich history

By Isabelle Mainville B. Sc. Microbiologie, Food Research and Development Center

Food Research and Development Centre

Agriculture et Agri-Food Canada

Part 1

In 1998, my supervisor announced that we’d be studying kefir to find out more about its microbial flora. Kefir? What on earth is that? I’d never even heard of it! That’s when my history with kefir began. But kefir’s own history started many, many years ago…in the earliest Antiquity.

The term kefir can be traced back to a region in Russia between the Black and Caspian seas known as the Caucasus, which is divided by the Caucasus Mountains, where kefir is believed to have originated. In ancient times, nomads would carry reindeer, goat, ewe and cow milk in pouches made of animal stomachs. The bacteria and enzymes in these pouches would cause the milk to ferment, transforming it into a thick and sour beverage that could keep for long periods of time. Through enzymatic action, the set milk that remained in the pouch – the very first kefir grains – would ferment the new fresh milk that was poured in.

 Today, kefir is made by adding kefir grains to milk. Kefir grains look a lot like tapioca or small cauliflower clusters and contain proteins, polysaccharides (complex carbohydrates that make the grains sticky) and different types of bacteria and yeasts. Through the centuries, the composition of the kefir grains has remained remarkably stable. Even if kefir is now found throughout the world, its flora is still rooted in the original grains.

 Kefir doesn’t taste like yogurt because the microorganisms used for fermentation are completely different. Kefir grain yeasts produce carbon dioxide, which carbonates the beverage. The yeast fermentation makes kefir slightly alcoholic (0.5%).

 Russians traditionally consume a lot of kefir. The beverage is even given to children since kefir is believed to have health benefits¹ . In hospitals, premature babies and their mothers drink kefir. In fact, the protein hydrolysis that takes place during the fermentation process makes the milk easier to digest than unfermented milk² .

Canadians are less familiar with kefir, but the beverage is becoming increasingly popular. It’s sold as a product that contains probiotics, which are known to be healthy³ bacteria. There is actually a strong connection between the different types of microorganisms found in kefir’s flora. This relationship is known as symbiosis…it’s practically a love story!

Stay tuned for my next blog on kefir. You’ll learn more about our research into the different bacterial and yeast species found in kefir and kefir labelling in Canada.

1)     Edward R. Farnworth, Isabelle Mainville. 2008. Kefir – A fermented milk product. In: Handbook of fermented functional foods. 2^nd. Edition. CRC Press. Boca Raton, FL. USA.

2)     http://www.hc-sc.gc.ca/fn-an/label-etiquet/claims-reclam/probiotics_qa-qr_probiotiques-fra.php

3)     Véronique Ninane, Radegonde Mukandayambaje, Gilbert Berben. 2009. Probiotiques, aliments fonctionnels et kéfir: le point sur la situation règlementaire en Belgique et sur les avancées scientifiques en matière d,évaluation des effets santé du kéfir. Biotechnol. Agron. Soc. Environ. 13(3) : 459-466.