416 Chapter 16
The cultures associated with health bene-
fi ts are yogurt bacteria ( Streptococcus ther-
mophilus and Lactobacillus delbrueckii spp.
bulgaricus ), other lactobacilli, and bifi dobac-
teria (Chandan and Shah, 2006 ). Yogurt
organisms possess several documented health
attributes. To bolster probiotic function, most
commercial yogurt is generally supplemented
with various species of Lactobacilli and
Bifi dobacteria. Yogurt starter bacteria, Lb.
delbrueckii ssp. bulgaricus and Streptococcus
thermophilus , are also thought to act as pro-
biotics because of their health - promoting
effects. In particular, yogurt bacteria have
been scientifi cally demonstrated to assist in
lactose digestion, reduce or prevent diarrhea
episodes, and strengthen immune defenses of
the host. They are reported to persist and
remain viable throughout the human gastro-
intestinal tract. The continuous ingestion of
live products ensures abundant numbers to
maintain their functional status. Even with
intestinal isolates such as Lb. acidophilus , it
is necessary to dose regularly rather than to
assume that a few doses allow the organisms
to colonize the gut permanently. The reported
health benefi ts (Pannell and Schoenfuss,
2007 ) associated with yogurt and probiotic
cultures include:- Stimulating the immune system
- Improving digestive regularity and allevi-
ating constipation - Reducing symptoms of lactose intolerance
- Reducing risk factors for colon cancer
initiation - Increasing calcium absorption
- Reducing the risk of cardiovascular disease
by lowering serum cholesterol - Alleviating infl ammatory bowel disease
and irritable bowel syndrome by restoring
the normal balance of gastrointestinal
microfl ora - Enhancing resistance to colonization by
pathogenic organisms
nutrients of milk, live cultures, and products
of the metabolic activities of starter microor-
ganisms. They particularly contain live and
active cultures in signifi cant numbers to
bestow physiological benefi ts to the con-
sumer. Fundamentally, bacterial mass content
and the products of the lactic fermentation
distinguish yogurt from milk.
Probiotics and Benefi cial Cultures are
foods or supplements containing concen-
trates of defi ned strains of living microorgan-
isms that, upon ingestion in certain doses,
exert health benefi ts beyond inherent basic
nutrition. Probiotics and associated ingredi-
ents may add an attractive dimension to cul-
tured dairy foods by conferring special
functional attributes.
Several hundred bacterial species inhabit
the distal regions of the human digestive
tract. Their population exceeds the total
cell count in human body. Functions of the
intestinal fl ora include modulation of cell
growth and differentiation, antagonistic
activity against pathogens and other infec-
tions, immune stimulation of gut - associated
lymphoid tissue, reduction of blood lipids,
and biosynthesis of vitamins. The colonies
of diverse gut bacteria exist in equilibrium
in healthy individuals. Factors such as
stress, age, gastrointestinal disturbances, and
antibiotic therapy are known to upset the
balance of gut microfl ora and result in
malfunctioning of their digestive and meta-
bolic effects. Probiotics help restore the
balance.
Milk is an excellent medium to carry or
generate live and active cultured dairy prod-
ucts (Chandan and Shah, 2006 ; Shah, 2006 ;
Vasilijevic and Shah, 2007 ). The buffering
action of the milk proteins keeps the probiot-
ics active during their transit through the gas-
trointestinal tract. In general, worldwide
consumption of fermented milk products has
increased due to their high nutritional profi le,
unique fl avor, desirable texture, and remark-
able safety against food - borne illness.