Biomedical Engineering Reference
In-Depth Information
pathogens belonging to
Salmonella
genus in minced beef meat (Hayouni et al.
2008
).
The antibacterial activities of both EOs in minced beef meat were clearly evident
however; their addition had notable effects on the fl avour and taste of the meat at
concentrations more than 2 % for
S. molle
and 1.5 % for
S. offi cinalis
. One solution
to the above mentioned problem may be the use of combinations of different food
preservation systems.
Inhibition of
E. coli
O157:H7,
S. typhimurium
, and
L. monocytogenes
by grape
seed extract (ActiVin) and pine bark extract (Pycnogenol) and the effect of these
natural extracts on the oxidative stability of raw ground beef were studied (Ahn
et al.
2004
). The numbers of
E. coli
O157:H7,
L. monocytogenes
, and
S. Typhimurium
declined in raw ground beef treated with 1 % Pycnogenol after 9 days of refriger-
ated storage. ActiVin (1 %) and oleoresin rosemary (1 %) resulted in an approxi-
mately 1-log cfu/g reduction in the populations of all three pathogens after 9 days.
It was suggested that these natural extracts have potential to be used with other
preservative methods to reduce pathogenic numbers, lipid oxidation, and colour
degradation in ground beef.
Natural antimicrobials in ready
-
to
-
eat products
: The effect of natural antimicrobi-
als such as EDTA, lysozyme, rosemary and oregano oil and their combinations, on
the shelfl ife of semi cooked coated chicken fi llets stored under vacuum packaging
was reported by Ntzimani et al. (
2010
). Among the antimicrobial combinations
examined, the treatments vacuum packaging, EDTA lysozyme solution and rose-
mary oil combination and vacuum packaging, EDTA lysozyme solution and oreg-
ano oil combination were the most effective against the growth of Gram-negative,
Gram-positive bacteria, and to a lesser extent on yeasts and produced a shelfl ife
extension of 7-8 days, as compared to the control samples.
Effi cacy of chitosan-coated plastic fi lms containing nisin, sodium lactate (SL),
sodium diacetate, potassium sorbate (PB) and sodium benzoate (SB) against
L.
monocytogenes
on cold-smoked salmon was observed (Ye et al.
2008b
). The fi lm
incorporating SL was the most effective, completely inhibiting the growth of
L.
monocytogenes
during 10 days of storage.
L. monocytogenes
in samples packaged
in the other four antimicrobial fi lms grew, but the increase in counts was lower than
the control. The workers also found that chitosan-coated plastic fi lms with 4.5 mg/
cm
2
SL, 4.5 mg/cm
2
SL-0.6 mg/cm
2
PS and 2.3 mg/cm
2
SL-500 IU/cm
2
nisin were
the most effective and completely inhibited the growth of
L. monocytogenes
on
smoked salmon for at least 6 weeks.
The effect of rosemary extract, chitosan and
-tocopherol, added individually or
in combination, on microbiological parameters and lipid oxidation of fresh pork
sausages was investigated (Georgantelis et al.
2007
). Chitosan addition showed sig-
nifi cant inhibition of microbial growth, while the lowest microbial counts were
obtained in the samples containing both chitosan and rosemary, indicating a possi-
ble synergistic effect. Shelf life of samples containing chitosan was almost doubled
compared to the remaining samples.
Studies have shown the antimicrobial activity of oregano and two of its major
components, carvacrol and thymol (Exarchou et al.
2002
; Seaberg et al.
2003
; Ahn
et al.
2004
). Cranberry fruit contains a wide range of phenolic phytochemicals, and
ʱ
