Meat Packaging 253Vacuum Packaging of Meat
Vacuum packaging (VP) was one of the ear-
liest forms of MAP methods developed com-
mercially and still is extensively used for
products such as primal cuts of fresh red meat
and cured meats (Parry 1993 ). An example
of vacuum packed meat is presented in Figure
13.4. The fi rst signifi cant commercial appli-
cation was for vacuum packaging of whole
turkeys using rubber stretch bags (Purdue
1997 ). VP extends the storage life of chilled
meats by maintaining an O 2 defi cient envi-
ronment within the pack (Bell et al. 1995 ).
Vacuum packs are comprised of evacuated
pouches or vacuum skin packs, in which a
fi lm of low gas permeability is closely applied
to the surface of the product. Preservative
effects are achieved by the development of
an anaerobic environment within the packanoxic meat, and because packaging materi-
als that are impermeable to gases are mostly
opaque (Gill 2003 ). The inclusion of O 2 in
CAP systems at low levels can have a delete-
rious effect on meat color. The inclusion of
just 100ppm oxygen can cause this discolor-
ation, but this is usually transient, since the
metmyoglobin is reduced to myoglobin,
usually within four days, as anoxic condi-
tions are established and maintained (Gill
and Jones 1994 ). However, O 2 scavengers
may be used in CAP systems to prevent the
formation of metmyoglobin, if very low
levels of O 2 are accidentally incorporated
during pack fi lling. Buys (2004) found that
the inclusion of an oxygen scavenger ensured
that retailed bulk - packaged pork chops held
in approximately 100% CO 2 were still accept-
able to a consumer panel after 14 days of
storage.
Figure 13.3. An overview of the variation found in the mean data from the ANOVA - Partial Least Squares
Regression (APLSR) correlation loadings plot for each of the 4 MAP treatment groups. Shown are the loadings
of the X and Y variables for the fi rst 2 PCs for = days and the individual MAP treatments, • = sensory
descriptor and instrumental variables. Im (Immediate) = meat samples cooked immediately after opening of the
MA packaging and presented to panelists. Dis (Dissipate) = meat samples left 30 min in ambient air to let any
CO 2 dissipate, then cooked and presented to panelists. The concentric circles represent 100% and 50%
explained variance, respectively. (Adapted from O ’ Sullivan et al. 2010.)