264 Chapter 14
With conventional MAP, the headspace
gas originally introduced changes during
product storage. For example, carbon dioxide
dissolves in liquids at refrigerated tempera-
tures, and its permeability as with most
plastic fi lms is three to fi ve times greater than
that of oxygen, so it is diffi cult to continu-
ously maintain its concentration during shelf
life (Ozdemir and Floros 2004 ). Also, any
residual or acquired oxygen may lead to
Brochothrix growth and undesirable changes
in meat color. As a result of these changes, a
new generation of active packaging systems
has emerged. To extend meat product shelf
life, active packaging involves the incorpora-
tion of certain additives into packaging
systems, such as antimicrobial agents, oxygen
scavengers, carbon dioxide emitters, or chlo-
rine dioxide emitters (Kerry et al. 2006 ).
Oxygen scavengers are mostly available
as sachets attached to the package and utilize
one of several technologies: ascorbic acid
oxidation, iron powder oxidation, photosen-
sitive dye oxidation, or biological scavenging
systems (Coma 2008 ). Carbon dioxide
emitters usually rely on either ferrous car-
bonate or ascorbic acid/sodium bicarbonate
mixture. Not surprisingly, commercially
available systems often contain both an O 2
scavenger and a CO 2 emitter (Table 14.1 ).( < 0.15%) or high (80%) oxygen level in
MAP is to prevent rapid browning of red
meats due to metmyoglobin formation
(MacDougall and Taylor 1975 ; Mancini and
Hunt 2005 ). Complete removal of oxygen is
desirable to prevent meat oxidation but
results in a purplish meat color (Cornforth
and Hunt 2008 ). In the remainder of this
section we briefl y summarize the antimicro-
bial and commercial aspects of these systems.
Anaerobic CO - MAP, which uses low
levels of carbon monoxide (CO, 0.4%), CO 2
(20% to 30%), and nitrogen (remainder),
inhibits growth of aerobic spoilage psychro-
trophic bacteria due to the absence of oxygen.
Carbon monoxide fi xes a strong red color
associated with fresh red meats, resulting in
longer freshness perception by consumers.
Consumers have historical familiarity with
the red color of fresh meats as an indicator
of freshness. Because CO fi xes this red color,
products stored beyond their useful shelf life
may visually appear fresh yet have high bac-
terial counts resulting in spoilage. Consumers
also may be concerned with the use of CO
for this application because of the well -
known association of this gas with human
fatalities following inhalation exposure from
faulty combustion systems (Cornforth and
Hunt 2008 ).
Table 14.1. Commercial active packaging with scavenger/emitter gas - based systems
Technology Format Trade name Manufacturer
CO 2 emitter/O 2 scavenger Sachet, label, card Ageless ® Mistubishi Gas Chemical Co. (Japan)
O 2 scavenger Sachet Oxysorb ® Pillsbury Co. (USA)
CO 2 emitter Sachet FreshPax ® Multisorb Technologies Inc. (USA)
O 2 scavenger Label ATCO ® Standa Industrie (France)
O 2 scavenger Label FreshMax ® Multisorb Technologies Inc. (USA)
O 2 scavenger Film^1 OS2000 ® Sealed Air Corporation (USA)
O 2 scavenger Film, Sachet Bioka ® Bioka Ltd. (Finland)
O 2 scavenger Film^1 ZerO2 ® CSIRO and VisyPak (Australia)
O 2 scavenger Film^2 Ageless - OMAC Mistubishi Gas Chemical Co. (Japan)
CO 2 emitter/O 2 scavenger Sachet Freshilizer ® Toppan Printing Co. (Japan)
Chlorine dioxide generator Sachet Microsphere ® Bernard Technologies (USA)
CO 2 emitter Verifrais ® SARL Codimer (France)
CO 2 emitter Vitalon ® Toagosei Chemical Co. (Japan)1 UV light activated
2 Heat activated