Handbook of Meat Processing

(Greg DeLong) #1
Meat Packaging 251

concluded that the use of 0.4% CO during
storage in MAP improved beef color without
masking spoilage. Upon removal of product
from CO packaging, meat color (likely to be
a combination of COMb and OMb) deterio-
rated during display in a manner not different
from product exposed only to air. Thus, the
inclusion of 0.4% CO in conjunction with
O 2 will not infl uence color stability, metmyo-
globin - reducing activity, or O 2 consumption.
This is likely the result of greater formation
of oxymyoglobin (oxyMb) in atmospheres
containing 20 – 80% O 2 , which dominates or
limits the ability of carboxymyoglobin
(COMb) to form (Seyfert et al. 2007 ). COMb
is more resistant to oxidation than oxymyo-
globin, owing to the stronger binding of CO
to the iron - porphyrin site on the myoglobin
molecule (Wolfe 1980 ). However, one of
the main consumer fears relating to the use
of CO is the possible loss of quality due to
a break in the cold chain, causing deteriora-
tion in spite of its attractive appearance
(Wilkinson et al. 2006 ). Concern has been
expressed in the United States in the past that
such a system would mask spoilage that
could occur in fresh meat products (Eilert
2005 ). The FDA noted that while color did
not degrade in a package containing CO,
offensive odors could still form normally in
the product in the presence of CO (FDA
2004 ). Although there are distinct advantages
for the storage and display life of meat with
CO in VP or low O 2 MAP, consumers have
a negative image of CO because of its haz-
ardous nature and the concern that products
may appear fresher than they actually are
(Cornforth and Hunt 2008 ). The declaration
of CO for meat as generally recognized as
safe (GRAS) in the United States has a legal
basis (Boeckman 2006 ). The use of CO in the
primary package of fresh meat in the United
States is a major breakthrough. This will
allow for the wider distribution of case - ready
products and adequate shelf life needed to
achieve distribution of these products (Eilert
2005 ).

Carpenter et al. (2001) showed that con-
sumer preference for beef color was suffi -
cient to infl uence their likelihood to purchase,
but was not enough to bias taste scores. It is
likely that once a decision to purchase beef
is made in the market, whether the beef is
presented in the form of cherry red fresh -
bloomed beef, the brown of discounted beef,
or the purple of vacuum - packaged beef, con-
sumer eating satisfaction at home will depend
only on the beef quality attributes of tender-
ness, juiciness, and fl avor (Carpenter et al.
2001 ).


Low O 2 MAP Meat Packs

Low O 2 packaging systems have been readily
available for usage in the United States, but
are not as widely implemented as their high
O 2 counterparts (Eilert 2005 ). Low O 2 MAP
are generally packed with CO 2 (usually
enough to dissolve into the product) and also
N 2 , while residual O 2 may be present or
included during the packing process. The
CO 2 acts as the antimicrobial and N 2 as
the pack shape stabilizer (S ø rheim et al.
1997 ). For Low O 2 MAP in the United States,
carbon monoxide (CO) may also be used as
a gas for meat color enhancement. Within the
EU, only Norway adopted the use of CO
(0.3 – 0.5%) in primary packs in the mid
1980s; however, this practice has since
ceased, following a decision by the EU
Parliament committee in 2004 not to allow
the use of CO in meat packaging applications
(S ø rheim 2006 ).
Industrially, CO has been added to pack-
ages to eliminate the disadvantages of com-
mercial ultra - low O 2 MAP, because CO has
a high affi nity for myoglobin and forms a
bright cherry red color on the surface of beef
(S ø rheim et al. 1999 ; Luno et al. 2000 ;
Jayasingh et al. 2001 ; Hunt et al. 2004 ). CO
is a colorless, odorless and tasteless gas. It is
produced mainly through incomplete com-
bustion of carbon - containing materials
(S ø rheim et al. 1997 ). Hunt et al. (2004)

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