Chapter 14
Food Protection with
Modified Atmospheres
This chapter addresses the various methods of modified-atmosphere packaging (MAP) that are used
to alter the gaseous environment on and around foods for the purpose of extending self-life. By and
large, it consists of the various ways in which carbon dioxide (CO 2 ) is used as a food preservative.
It has been known since 1882 that increased concentrations of CO 2 will extend the self-life of fresh
meats, and the actual application of this gas to extend the self-life of red meats has been practiced
for many decades (Table 14–1). The effect of CO 2 on some plant products was recorded as early as
1821.
84 About 90% of boxed beef in the United States is packed under vacuum/MAP, and 90–95% of
fresh pasta sold in the United Kingdom is MAP.
76
DEFINITIONS
There has been a lack of consensus on the terminology that is used to describe the various ways
in which increased levels of CO 2 and decreased levels of O 2 are achieved. The most widely used
terminology is defined and briefly described below.
Hypobaric (Low Pressure) Storage
Foods are stored in air under low pressure, low temperature, and high humidity, all of which are
precisely controlled along with ventilation. The hypobaric state results in reduced concentrations of
O 2 , which also results in reduced fat oxidation. Atmospheres of about 10 mm Hg have been found
to be effective for meats and seafoods; 10–80 mm Hg for fruits and vegetables; and 10–50 mm Hg
for cut flowers (1 atm = 760 mm Hg). In one study using pork loins, a pressure of 10 mm Hg along
with a temperature of 0
◦ F and 95% humidity was up to six times more effective on self-life than air
storage.
49 This method was first outlined around 1960 by Stanley Burg, and a commercial hypobaric
container was developed in 1976 (Table 14–1). The use of hypobaric storage is limited, and is not
discussed further in this text.
351
Food Protection with
Modified Atmospheres
This chapter addresses the various methods of modified-atmosphere packaging (MAP) that are used
to alter the gaseous environment on and around foods for the purpose of extending self-life. By and
large, it consists of the various ways in which carbon dioxide (CO 2 ) is used as a food preservative.
It has been known since 1882 that increased concentrations of CO 2 will extend the self-life of fresh
meats, and the actual application of this gas to extend the self-life of red meats has been practiced
for many decades (Table 14–1). The effect of CO 2 on some plant products was recorded as early as
1821.
84 About 90% of boxed beef in the United States is packed under vacuum/MAP, and 90–95% of
fresh pasta sold in the United Kingdom is MAP.
76
DEFINITIONS
There has been a lack of consensus on the terminology that is used to describe the various ways
in which increased levels of CO 2 and decreased levels of O 2 are achieved. The most widely used
terminology is defined and briefly described below.
Hypobaric (Low Pressure) Storage
Foods are stored in air under low pressure, low temperature, and high humidity, all of which are
precisely controlled along with ventilation. The hypobaric state results in reduced concentrations of
O 2 , which also results in reduced fat oxidation. Atmospheres of about 10 mm Hg have been found
to be effective for meats and seafoods; 10–80 mm Hg for fruits and vegetables; and 10–50 mm Hg
for cut flowers (1 atm = 760 mm Hg). In one study using pork loins, a pressure of 10 mm Hg along
with a temperature of 0
◦ F and 95% humidity was up to six times more effective on self-life than air
storage.
49 This method was first outlined around 1960 by Stanley Burg, and a commercial hypobaric
container was developed in 1976 (Table 14–1). The use of hypobaric storage is limited, and is not
discussed further in this text.
351