Biomedical Engineering Reference
In-Depth Information
lethal processing step at the plant and contamination during slicing/handling at
retail or home (Lianou et al.
2007
). Both sets of bags were stored aerobically at 7 °C
for 12 days to simulate home storage.
L. monocytogenes
populations were signifi -
cantly lower during storage in turkey breast containing a combination of lactate and
diacetate compared to product without antimicrobials under both contamination
scenarios.
Antilisterial activity of nisin (Nisaplin), alone (400 and 800 IU/g) and in combi-
nation with 2 % sodium chloride was observed in raw buffalo meat mince (Pawar
et al.
2000
). The growth of
L. monocytogenes
in the treated groups was signifi cantly
inhibited compared to the control group. The degree of inhibition increased with
increasing concentration of nisin and decreasing storage temperature. Addition of
2 % sodium chloride in combination with nisin increased the effi cacy of nisin. The
effect of nisin and nisin/EDTA followed by vacuum packaging on the reduction of
B. thermosphacta
and
S. Typhimurium
counts on beef was investigated (Tu and
Mustapha
2002
). Growth of
B. thermosphacta
was completely inhibited by nisin
and nisin/EDTA. However, neither treatment showed signifi cant effects against
S. Typhimurium
. It was suggested that nisin or nisin/EDTA treatment, followed by
vacuum packaging under refrigerated conditions could increase the shelf life of
fresh beef.
Application in ready
-
to
-
eat products
: Juncher et al. (
2000
) found that two combina-
tions of hurdles, 2.0 % lactate + 0.5 % acetate or 2.0 % lactate + 0.25 % glucono-
delta-lactone (GdL), were able prevent growth of
L. monocytogenes
inoculated onto
sliced
saveloys
manufactured with 60 or 150 ppm nitrite. Changes in red colour and
lipid oxidation were low during storage at 5 °C and unaffected by the storage condi-
tion. A combination of 2.0 % lactate + 0.25 % GdL improved oxidative stability and
led to signifi cantly lower thiobarbituric acid reactive substances (TBARS) and
higher redness values. Levels of nitrosamines were also low with values near the
detection level. Although observed differences were small, members of a trained
sensory panel were able to distinguish control and treated product.
Karthikeyan et al. (
2000
) studied the extension of shelf life of the highly perish-
able Indian traditional meat product, chevon (caprine)
keema
, through the applica-
tion of hurdle technology. The hurdles used were water activity and pH as variable
hurdles while vacuum packaging, preservatives and heat treatment as constant hur-
dles. The product with a
w
at 0.90, pH at 5.8 was found most suitable. There was a
decrease in the growth rate of aerobic and anaerobic counts and complete inhibition
of
S. aureus
. It was also found that sensory scores for hurdle treated
keema
declined
upon storage and the product was well accepted up to the 3rd day and fairly accepted
up to 5th day whereas the
keema
prepared by the traditional method was acceptable
only on the fi rst day. The mutton curry was preserved by hurdle technology, employ-
ing various hurdles like water activity, pH, preservative, high temperature, low tem-
perature and oxido-redox potential to obtain convenience intermediate moisture
product (Das and Radhakrishna
2001
). The product having 37.68 % moisture,
33.15 % fat and pH at 5.58 was found stable for more than 4 months at ambient tem-
perature of 27 ± 2 °C and more than 6 months at refrigerated temperature of 3 ± 2 °C.
