364 Chapter 14
direct - to - vat adjunct inocula to control
Salmonella in French surface - ripened semi -
soft cheese made from raw milk.
Recently, a trade release entitled “ Pro-
tective Cultures ” by Danisco (2005b) defi ned
the appellation as follows: “ Protective cul-
tures are bacteria especially selected and
developed for their ability to control the
growth of pathogenic and/or spoilage micro-
organisms in fermented foods. ” The release
deals with protective cultures for both fer-
mented dairy products as well as meat prod-
ucts. The bacteria identifi ed for this function
are strains of Lactobacillus plantarum , Lac-
tobacillus rhamnosus, Lactobacillus sakei,
Lactobacillus paracasei, and Propionibac-
terium freudenreichii subsp. shermanii. With
the exception of Lactobacillus sakei , all of
the other species are associated with fer-
mented dairy products. Lactobacillus sakei is
more frequently encountered in fermented
meats, and is not reported to occur in fer-
mented dairy products.
Single cultures or combinations of these
species are sold for various applications
under the trade name HOLDBAC^ ™^. Specifi c
cultures in this series are recommended for
specifi c functions in different fermented
dairy products. The release recommends
the use of HOLDBAC^ ™^ for growth control
of Listeria in soft and smear cheese.
HOLDBAC^ ™^ LC is recommended for the
growth control of undesirable Leuconostoc ,
enterococci, and heterofermentative lactoba-
cilli in semi - hard and hard cheeses. Leuco-
nostocs are often implicated in late gas splits
in semi - hard cheese, and heterofermentative
lactobacilli also contribute to gas openings
and certain fl avor defects such as fermented
fl avors or fruitiness. For growth control of
yeasts and molds in fresh fermented dairy
products such as yogurt, sour cream, quark,
cottage cheese etc., HOLDBAC^ ™^ YM - B
and YM - C are recommended. Grattepanche
et. al (2008), on the basis of published reports,
mention that HOLDBAC^ ™^ YM - B consists
of Propionibacterium freudenreichi subsp.Branen et al. (1976) described the purifi ca-
tion of antimicrobial substances active
against Pseudomonas spp., elaborated by
Leuconostoc mesenteroides ssp. cremoris
and citrate - metabolizing Lactococcus lactis
subsp. lactis strains.
The repeated observations by various
researchers on the inhibitory effect of the
citrate - metabolizing Lactococcus subspecies
and its fl avor - generating properties culmi-
nated in the fi ling of patents by Sing (1976)
and Gonzalez (1984, 1986). The antimicro-
bial activity of Leuconostoc mesenteroides
ssp. cremoris also was noted by several
investigators (Mather and Babel, 1959 ; Marth
and Hussong, 1963 ; and Sorrels and Speck,
1970 ). Based on these fi ndings, Babel and
Mather (1961) patented the application of
Leuconostoc mesenteroides ssp. cremoris
in cream dressing for cottage cheese. Both
the citrate - fermenting Lactococcus lactis
ssp. lactis and Leuconostoc mesenteroides
ssp. cremoris are extensively used (as
chill additives as discussed in the previous
section) by the industry to control unwanted
spoilage and pathogenic/enterotoxigenic bac-
teria in creamed cottage cheese. In addition,
these organisms generate desirable diacetyl
fl avor during its initial holding in the cooler
and its distribution through the marketing
channels.
The patents fi led by Gonzalez (1984,
1986) on the use of lactose - negative and
citrate - permease - negative Lactococcus lactis
subsp. lactis (biovar diactylactis ) for chill
addition to extend the shelf - life were uniquely
designed for the cottage cheese market in
California, where high acidity and high
diacetyl fl avor did not fi nd favor with the
customers. In addition to its application in
cottage cheese in the United States, Cit +
Lactococcus lactis subsp. lactis was found to
be inhibitory to Salmonella in broth, milk,
and cottage cheese systems (Vedamuthu
et al., 1966 ). Based on these observations,
currently, frozen concentrated cultures of this
bacterium are widely used in Europe as a