Functional Ingredients from Dairy Fermentations 363probiotic bacteria. Furthermore, the cheese
core could be considered an anaerobic envi-
ronment with a very low redox potential (E h )
of about − 250 mv (Beresford et. al., 2001 ),
which is favorable for the survival of probi-
otic bacteria. Grattepanche et al. (2008) have
summarized the data from various studies
using a variety of cheeses, and shown that
cheese indeed could serve as a good carrier
to deliver high numbers of viable probiotic
cultures. The authors, however, caution that
incorporation of probiotics in cheese could
lead to compositional, body, texture, and
fl avor deviations in cheese. They suggest that
careful probiotic strain selection and process
adjustments are necessary to overcome such
cheese quality problems. They stress the need
for further research in these areas.Biopreservatives: Live
Protective Cultures
The term protective cultures can be applied
to traditional starter and associated bacteria
used in the production of fermented dairy
products to protect them from spoilage and
pathogenic and enterotoxigenic bacteria by
their suppressive or inhibitory activity.
Fortuitously, the fl avor bacteria that are
added to cottage cheese to enhance desirable
dairy notes such as diacetyl fl avor were found
to exert a suppressive effect on spoilage and
pathogenic and enterotoxigenic fl ora often
encountered in this product. The inhibitory
properties of live cells of citrate fermenting
Lactococcus lactis subsp. lactis (also referred
to as biovar diacetylactis ) were reported by
Vedamuthu et al. (1966) to inhibit Gram -
negative spoilage bacteria in creamed cottage
cheese, as well as enteropathogenic Gram -
negative bacteria such as Salmonella spp.
The inhibitory effect of the same bacterium
on spoilage and pathogenic bacteria in milk
and broth systems was reported by Daly
et al. (1970a,b; 1972) and on Psueudomonas
spp. by Pinheiro and Parmalee (1968).Adding probiotic strains after fermenta-
tion is desirable because the probiotic benefi t
supposedly depends upon the viable numbers
of the probiotic strains at the time of con-
sumption by the consumers. The inability of
probiotic Lactobacillus acidophilus and bifi -
dobacterial strains to compete with the yogurt
starter bacteria during fermentation, coupled
with the suppressive effect of hydrogen per-
oxide generated by LB, makes it diffi cult to
meet the arbitrary standards for viable counts
for probitics that are generally accepted by
the yogurt industry. The probiotic yogurt
industry is self - regulated, because there are
no offi cial regulatory requirements. Further,
there are no recognized accurate standard
methods for the differential enumeration of
probiotic strains in the presence of yogurt
starter bacteria. Until this shortcoming is
resolved, standards for probiotic yogurt is
unforeseeable.
Recently, Grattepanche et al. (2008) have
presented the pros and cons of cheese as a
vehicle for delivering probiotic bacteria.
Champagne et al. (2005) reported that probi-
otic cultures consisting of Lb. acidophilus
and bifi dobacteria are mostly added to milk,
yogurt, ice cream, and desserts. However, the
conditions encountered in these products are
very different from those occurring in the
natural habitat of probiotic bacteria, namely,
the gastrointestinal tract of humans. The
product composition and the microecological
environment could have deleterious effects
on the viability of probiotic strains, which
is considered to be the most important pre-
requisite for benefi cial health effects of
probiotics.
Roy (2005) has suggested that a minimum
intake of 10^8 to 10^9 viable cells of probiotics
is necessary to provide a therapeutic effect.
Boylston et al. (2004) argued that because of
its relatively limited acidity, low oxygen
level, high lipid content (which provides pro-
tection), and low storage temperatures,
cheese is a suitable carrier for delivering live