aware of.
Yogurt remained an exotic curiosity in
Europe until early in the 20th century, when
the Nobel Prize–winning immunologist Ilya
Metchnikov connected the longevity of
certain groups in Bulgaria, Russia, France,
and the United States with their consumption
of fermented milks, which he theorized would
acidify the digestive tract and prevent
pathogenic bacteria from growing (see box, p.
47). Factory-scale production and milder
yogurts flavored with fruit were developed in
the late 1920s, and broader popularity came in
the 1960s with Swiss improvements in the
inclusion of flavors and fruits and the French
development of a stable, creamy stirred
version.
The Yogurt Symbiosis By contrast to the
complex and variable flora of traditional
yogurts, the industrial version is reduced to
the essentials. Standard yogurt contains just