Biomedical Engineering Reference
In-Depth Information
Ovotransferrin is the main component in the antimicrobial defense system of
hens' egg. Antimicrobial activity of ovotransferrin is mainly due to its iron-binding
capacity, but direct interactions with the bacterial surface also seem to play an
important role in contributing to its inhibitory activity (Moon et al.
2011
).
Ovotransferrin, nisin, and their combinations had strong antilisterial activity in BHI
broths. However, addition of ovotransferrin to frankfurters did not inhibit growth of
L. monocytogenes
. When nisin (1,000 IU/frankfurter) was applied, an early bacteri-
cidal effect followed by delayed growth was observed (Moon et al.
2011
). However,
no differences were reported in the antilisterial effect when the same nisin concen-
tration was applied in combination with ovotransferrin (40 mg/frankfurter). The
observed differences could be explained by the infl uence of factors such as interac-
tion with food substrate or a higher iron content in meat.
Incorporation of nisin into bologna-type sausages during mixing of ingredients
inhibited the growth of spoilage LAB during further storage at 8 °C of the resulting
vacuum-packed sausages (Davies and Delves-Broughton
1999
). The effectiveness
of nisin against several bacteria (such as
B. thermosphacta
,
L. curvatus
,
Ln. mesen-
teroides
,
L. monocytogenes
,
Salmonella
sp. and
E. coli
O157:H7) in ham and/or
bologna sausages increased in combination with lysozyme and EDTA (Gill and
Holley
2000a
,
b
). In fresh pork sausages, a combination of nisin and organic acids
reduced the viable counts of
Salmonella
Kentucky and
S. aureus
(Scannell et al.
1997
). The combination of sodium citrate or sodium lactate with nisin or lacticin
3147 was also reported to increase the inhibition of
Listeria
and
C. perfringens
in
fresh pork sausages (Scannell et al.
2000a
).
Pediocin activity was increased when added in combinations with sodium diace-
tate or sodium lactate against
L. monocytogenes
on frankfurters or
L. monocyto-
genes
and
Yersinia enterocolitica
on cooked poultry cuts stored under MAP at
3.5 °C (O'Sullivan et al.
2002
; Chen and Hoover
2003
; Aymerich et al.
2008
). The
antilisterial activity of pediocin in slurries prepared from ready-to-eat turkey breast
meat increased greatly when tested in combination with diacetate, due to synergistic
effects between the two antimicrobials (Schlyter et al.
1993
). When commercial
beef franks were dipped for 5 min in three antimicrobial solutions: pediocin
(6,000 AU), 3 % sodium diacetate and 6 % sodium lactate combined, and a combi-
nation of the three antimicrobials, reductions of
L. monocytogenes
populations
ranged between 1 and 1.5 log units and 1.5-2.5 log units after 2 and 3 weeks of
storage, respectively, at 4 °C (Uhart et al.
2004
). These results indicated that the use
of combined antimicrobial solutions for dipping treatments is more effective at
inhibiting
L. monocytogenes
than treatments using antimicrobials such as pediocin
separately (Uhart et al.
2004
). In another study, the effects and interactions of tem-
perature (56.3-60 °C), added sodium lactate (0-4.8 %) and sodium diacetate
(0-0.25 %) and dipping in pediocin (0-10,000 AU) on
L. monocytogenes
in bologna
were studied by Maks et al. (
2010
). Combination treatments increased or decreased
D
-values, depending on the temperature. Pediocin (2,500 and 5,000 AU) and heat
decreased
D
-values, but pediocin exhibited a protective effect at higher concentra-
tions (
7,500 AU). The results showed that interactions between additives in for-
mulations can vary at different temperatures/concentrations, thereby affecting
thermal inactivation of foodborne pathogens in meat products.
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