Biomedical Engineering Reference
In-Depth Information
effect on
Enterobacteriaceae
or
Pseudomonas
spp., with fi nal populations of about
4 log CFU/cm
2
. Nevertheless, the active packaging reduced the release of volatile
metabolites in the headspace of beef with a probable positive impact on meat qual-
ity. Recycling of industrial wastes into useful products is a growing trend not only
in the food industry but in many other fi elds as well. In a recent and innovative
study, a novel poly(lactic acid)/sawdust particle biocomposite fi lm with anti-listeria
activity was developed by incorporation of pediocin PA-1/AcH (Woraprayote et al.
2013
). It was reported that sawdust particle played an important role in embedding
pediocin into the hydrophobic PLA fi lm. Application of the activated fi lm as a food-
contact antimicrobial packaging on raw sliced pork effi ciently inhibited
L. monocy-
togenes
during chill storage.
The bacteriocin 32Y (from
Lactobacillus curvatus
32Y) was used to develop an
industrially produced activated plastic fi lm (Mauriello et al.
2004
). In experiments
of food packaging with pork steak and ground beef (simulating hamburgers) con-
taminated by
L. monocytogenes
V7, highest antimicrobial activity was observed
after 24 h at 4 °C, with a decrease of about 1 log of the
L. monocytogenes
population
(Mauriello et al.
2004
). The lactocins 705 and AL705 are produced by
L. curvatus
CRL705. Lactocin 705 has antagonist effect against LAB and
B. thermosphacta
,
while AL705 is active against
Listeria
species (Castellano and Vignolo
2006
). Both
bacteriocins retained antimicrobial activity when included in polymer matrices such
as LDPE (Blanco et al.
2008
,
2012
) and gluten (Blanco Massani et al.
2014
). In tri-
als with
L. curvatus
CRL705 immobilized bacteriocins, a bacteriostatic effect
against
L. innocua
7 was observed in both synthetic (Cryovac fi lms) and gluten
activated packages until the fourth week of storage (Blanco Massani et al.
2014
).
The process operations for manufacture of minced meats facilitate inoculation of
contaminating bacteria in the meat batter. Therefore, the presence and multiplica-
tion of foodborne pathogens in minced meats should be controlled. One study
showed that the single addition of nisin extended the lag phase of
L. monocytogenes
inoculated into minced buffalo meat (Pawar et al.
2000
). In minced meats, the com-
bination of bacteriocins with plant essential oils at levels where they would not
impart undesirable fl avour is being considered as a way to increase inactivation of
L. monocytogenes
and inhibition of
Salmonella
Enteritidis (Solomakos et al.
2008
;
Govaris et al.
2010
). Antilisterial activity of nisin in minced beef increased greatly
in combination with thyme essential oil. The combination of essential oil at 0.6 %
with nisin at 1,000 IU/g decreased the population of
L. monocytogenes
below the
offi cial limit set by European Union during storage at 4 °C for at least 12 days
(Solomakos et al.
2008
). At that concentration, the thyme oil did not impart undesir-
able fl avour. Promising results have also been reported on inhibition of
S
. Enteritidis
in sheep minced meat by a combination of nisin and oregano essential oil (Govaris
et al.
2010
), while the single treatment of minced sheep meat with nisin at 500 or
1,000 IU/g had no activity against
S
. Enteritidis. The combination of the oregano
essential oil at 0.6 % with nisin at 500 IU/g showed stronger antimicrobial activity
against
S
. Enteritidis than the single oregano essential oil at 0.6 % but lower than the
combination with nisin at 1,000 IU/g (Govaris et al.
2010
). Best results were
reported for the combinations of oregano essential oil at 0.9 % with nisin at 500 or
