483
Chapter 37
Control by Modified
Atmosphere (or Reducing
o-R Potential)
introduction
Humans probably recognized, in the early ages of agriculture and animal husbandry, that many
foods were susceptible to quality loss when stored in air. This probably led to the preservation of
foods in approximately 6000 b.c. by initially excluding air in pits and later, with the invention of
pottery and baskets, in large vessels and containers. Grains, semidry products, some fermented
products, concentrated syrups and molasses, and similar products are still stored in large, closed,
airtight vessels in many parts of the world to prevent insect infestation and the growth of molds
and yeasts. However, this method of changing the gaseous environment to preserve more perishable products, such as fresh meat, fish, fruits and vegetables, and other processed products,
originated in the early 20th century. During the 1920s and 1930s, studies revealed that by using
CO 2 in higher concentrations (4%–100%), the growth of molds on fresh meats could be greatly
reduced, and ripening of fruits and vegetables could be prolonged. In the 1960s, refrigerated beef
carcasses were transported by ship from New Zealand and Australia to other countries in controlled CO 2 -rich environments.
In the 1960s, the availability of suitable plastic materials for packaging and the necessary
technology helped develop methods to preserve foods in different-sized packages in an altered
atmosphere. This was achieved either by vacuum packaging or by gas flushing the package with
one gas or a mixture of gases. During storage, the gaseous environment could change because of
the metabolic activities of the food products and microorganisms and also as a result of the permeability of gases from the air through the packaging materials. 1,2
In recent years, modification of the storage environment to preserve foods has become one of
the methods used most often. The desire of consumers for fresh foods, foods that have been given
fewer processing treatments to maintain nutritive value, and without undesirable preservatives, as
well as the availability of the necessary technology, have helped in the economical production of
Chapter 37
Control by Modified
Atmosphere (or Reducing
o-R Potential)
introduction
Humans probably recognized, in the early ages of agriculture and animal husbandry, that many
foods were susceptible to quality loss when stored in air. This probably led to the preservation of
foods in approximately 6000 b.c. by initially excluding air in pits and later, with the invention of
pottery and baskets, in large vessels and containers. Grains, semidry products, some fermented
products, concentrated syrups and molasses, and similar products are still stored in large, closed,
airtight vessels in many parts of the world to prevent insect infestation and the growth of molds
and yeasts. However, this method of changing the gaseous environment to preserve more perishable products, such as fresh meat, fish, fruits and vegetables, and other processed products,
originated in the early 20th century. During the 1920s and 1930s, studies revealed that by using
CO 2 in higher concentrations (4%–100%), the growth of molds on fresh meats could be greatly
reduced, and ripening of fruits and vegetables could be prolonged. In the 1960s, refrigerated beef
carcasses were transported by ship from New Zealand and Australia to other countries in controlled CO 2 -rich environments.
In the 1960s, the availability of suitable plastic materials for packaging and the necessary
technology helped develop methods to preserve foods in different-sized packages in an altered
atmosphere. This was achieved either by vacuum packaging or by gas flushing the package with
one gas or a mixture of gases. During storage, the gaseous environment could change because of
the metabolic activities of the food products and microorganisms and also as a result of the permeability of gases from the air through the packaging materials. 1,2
In recent years, modification of the storage environment to preserve foods has become one of
the methods used most often. The desire of consumers for fresh foods, foods that have been given
fewer processing treatments to maintain nutritive value, and without undesirable preservatives, as
well as the availability of the necessary technology, have helped in the economical production of