Dairy, fish and meat products
High concentrations of bacteria (4106–107 CFUg1) in
food are typically required before their activity is sufficient
to influence the sensory properties of a product. For this to
happen, occurrence and growth kinetics are the key parameters,
and databases, including ComBase, are available to
determine the effect of food storage conditions and product
characteristics on growth of specific bacteria (McMeekin
et al., 2006). However, information on carnobacteria has not
yet been included in such databases.
Carnobacterium maltaromaticum and another Carnobacterium
sp. have been isolated from milk (Miller et al., 1974;
EF204312), and they, in addition to C. divergens, have been
detected in soft cheeses, including mold-ripened brie (Millie`
re et al., 1994), mozzarella (Morea et al., 1999), Camembert
(Cailliez-Grimal et al., 2005) and other types (Millie`re &
Lefebvre, 1994, Cailliez-Grimal et al., 2007). The high
concentration of C. divergens in the curd of mozzarella,
exposed to 10–37 1C during processing, is in agreement with
the maximum growth temperature (40 1C) of this species
(Collins et al., 1987).
The occurrence of Carnobacterium in dairy products (and
other foods) is most likely underreported. This is due to the
common use of acetate containing media, particularly MRS
agar (Oxoid CM361) or Rogosa agar (Oxoid CM0627), for
enumeration of LAB (de Man et al., 1960). Growth of
Carnobacterium is inhibited by acetate, and both MRS and
Rogosa agar media significantly underestimate concentrations
in food (Leblanc et al., 1997; Sakala et al., 2002;
Hammes & Hertel, 2003; Susiluoto et al., 2003; Chenoll
et al., 2007).
Carnobacterium divergens and C. maltaromaticum are
present in seafood and are able to grow to high concentrations
in different fresh and lightly preserved products.
Studies of naturally contaminated products suggest which
storage conditions and product characteristics select for
carnobacteria as compared to the other bacteria present in
seafood. For chilled fresh seafood, we have found no reports