For centuries, lactic acid bacteria have been used in the
preservation of food for human consumption. The primary objective of fermenting
milk was to preserve this precious fluid which otherwise would deteriorate
under high temperatures. This process is thought to have originated in the
Middle East. Historically, fermented milk products have constituted a vital
component of the human diet for many in Asia, Eastern Europe and Africa.
When people talk about Probiotics, what usually comes to
mind is Yogurt, one of the oldest and most popular fermented dairy products in
the world. This semisolid product is the result of the fermentation of milk by
lactic acid bacteria. Such fermentation is caused by the activity of two live
Probiotic cultures called Streptococcus thermophilus and Lactobacillus
combination of bacteria produces an
enzyme called lactase. This enzyme hydrolyzes
(a chemical process in which a
specific molecule is split into two parts by the addition of amolecule of water) the natural milk sugar lactose,
which is the first step in the production of lactic acid. The acid then lowers
the pH and gently curdles the milk as it imparts a tart flavor.
Recently this cultured
dairy food has gained great popularity in the United States in the form of many
brands of yogurt. The numbers are impressive: In the past two decades the
increase of consumption of yogurt went from 1 pound to 4.2 pounds per capita.
This impressive boost in consumption shows an increased awareness of the
importance of Probiotics in our everyday diet.
Claims of health benefits
from the regular consumption of cultured (fermented) dairy products circulated
for centuries without scientific proof. The first scientific proof was provided
in 1908 when Nobel Prize winner Russian
Professor Elie Metchnikoff provided research to support the claim that
probiotic organisms may be responsible for specific health benefits.
Dr. Metchnikoff studied the history of the consumption
of yogurt, finding that it dated back to the dawn of civilization. Bulgarians,
Serbs and others made yogurts from cow milk, sheep milk, goat milk, and even buffalo
milk. Metchnikoff was intrigued by the fact that so many people in Bulgarian
villages lived beyond the age of 100 years and he wanted to know why. He found
that this longevity could be attributed to their regular consumption of large
quantities of yogurt fermented using lactic-acid-producing bacteria. The
consumption of yogurt was found to inhibit pathogens and detoxify their
intestinal systems. He then appropriately named these bacteria “Lactobacillus
Several years passed before additional studies were completed to determine why consumption of
yogurt provided these specific health benefits. Today there is a steady flow of scientific findings
supporting this conclusion.