Handbook of Meat Processing

(Greg DeLong) #1
Freezing/Thawing 115

1200

1000

800

600

400

Storage life of beef (days) 200

0
–40 –30 –20
Temperature (°C)

–10 0

Figure 5.2. Experimental data on the frozen storage life of beef at different temperatures.


1200

1000

800

600

400

Storage life of pork (days) 200

0
–40 –30 –20
Temperature (°C)

–10 0

Figure 5.3. Experimental data on the frozen storage life of pork at different temperatures.


storage, but considerable scatter between
results at any one temperature.
There is some evidence that consumer
panels are often not very sensitive to quality
changes. In a study on the quality of lamb
stored at − 5 ° C and − 35 ° C, a consumer
panel could not tell the difference between
samples, although a trained taste panel could
differentiate and scored the samples stored
at − 5 ° C as rancid (Winger 1984 ). Some
researchers, such as Jul (1982) , have ques-
tioned the wisdom of storage below − 20 ° C


and have asked whether there is any real eco-
nomic advantage in very low temperature
preservation.

Temperature Fluctuation

Generally, fl uctuating temperatures in storage
are considered to be detrimental to the
product. However, it has been reported that
repeated freeze - thaw cycles do not cause any
essential change in the muscle ultrastructure
(Carrol et al. 1981 ) and that several freeze -
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