Biomedical Engineering Reference
In-Depth Information
et al.
2008
). Pediococci are preferred as starters in certain products (rather than
lactobacilli), e.g. in American-style sausages fermented at higher temperatures.
Bacteriocin-producing pediococci were proposed as indigenous starter cultures in
the fermentation of Urutan, a Balinese traditional dry fermented sausage (Antara
et al.
2004
). One advantage is that pediocin PA-1 producers do not inhibit bacteria
relevant to the fermentation such as staphylococci and micrococci (Gonzalez and
Kunka
1987
).
Enterococci are often part of the normal microbiota in meat fermentations, and
have demonstrated to be effective as antilisteria agents in fermented meats, being
also able to inhibit
S. aureus
(Foulquié Moreno et al.
2003
; Aymerich et al.
2008
;
Galvez et al.
2008
). However, their application in foods is controversial because of
their potential virulence as opportunistic pathogens and also as carriers of antimi-
crobial resistance genes. The bacteriocinogenic strains
E. faecium
CCM 4231 and
E. faecium
RZS C13 strongly inhibited the growth of
Listeria
spp. in sausage fer-
mentations (Callewaert et al.
2000
), and
Enterococcus casselifl avus
IM 416K1
(producer of enterocin 416K1) was able to suppress
L. monocytogenes
in artifi cially
inoculated "cacciatore" Italian sausages (Sabia et al.
2003
). During sausage fermen-
tation, inoculated
Enterococcus faecalis
A-48-32 (producer of the broad-spectrum
cyclic enterocin AS-48) or its transconjungant
E. faecium
S-32-81, reduced the con-
centration of
L. monocytogenes
down to undetactable levels within 7 or 6 days of
incubation at 20 °C (Ananou et al.
2005a
). Similarly, strain A-48-32 inhibited
growth of
S. aureus
and reduced viable cell counts to 1 log CFU/g at the end of
fermentation (Ananou et al.
2005b
). Strain
E. faecalis
CECT 7121 (isolated from
natural corn silage, and producer of the broad-spectrum enterocin MR99) is inter-
esting because it is devoid of the genes for haemolysin and gelatinase production,
and does not produce biogenic amines (Sparo et al.
2008
). When tested in the manu-
facture of craft dry-fermented sausages, the sausages inoculated with
E. faecalis
CECT 7121 had lower viable counts of
Enterobacteriaceae
,
S. aureus
and other
Gram-positive cocci at the end of fermentation (2 days), with no detectable entero-
bacteria and
S. aureus
at the end of drying (21 days).
E. faecalis
CECT7121 did not
affect the growth of
Lactobacillus
spp. but it displaced the autochthonous popula-
tions of enterococci (Sparo et al.
2008
).
The potential of bacteriocin-producing lactococci in meat fermentations has
been studied to a much less extent. Nisin-producing lactococcal strains isolated
from fermented sausages were suggested as adjunct cultures for improving the food
safety of meat fermented products manufactured under poor hygienic conditions
such as indigenous fermentations (Rodriguez et al.
1995
; Noonpakdee et al.
2003
).
Furthermore, it was reported that a transformant
L. lactis
strain producing lacticin
3417 signifi cantly reduced the populations of
L. innocua
and
S. aureus
in sausages,
although growth of the bacteriocin producer was markedly infl uenced by sausage
ingredients (Scannell et al.
2001
). In another study on manufacture of merguez, a
dry-fermented beef meat sausage, inoculation with the Bac + strain
L. lactis
subsp.
lactis
M signifi cantly reduced the levels of
L. monocytogenes
during the fermentation
phase (Benkerroum et al.
2003
). However, inoculation with a lyophilized culture of
the bacteriocin-producing strain
L. lactis
LMG21206 decreased
Listeria
counts to
