Atmosphere control around respiring biological materials

A method of controlling packaging atmospheres around respiring biological materials, the method comprising

• (A) providing a substantially closed chamber which (i) contains respiring biological materials surrounded by a packaging atmosphere, (ii) comprises a wall comprising an atmosphere control member (ACM) having a first surface in contact with the packaging atmosphere and a second surface in contact with an atmosphere outside the closed chamber, and (iii) comprises an inlet and an outlet;
• (B) providing a controller which can be operated so that gas is passed into the closed chamber through the inlet at a first rate and gas is removed from the closed chamber through the outlet at a second rate which is less than the first rate;
• and
• (C) operating the controller so that gas is passed into the closed chamber at the first rate and removed from the closed chamber at the second rate;
• whereby (i) the pressure on the first surface of the ACM is at least 2 inches of water pressure greater than the pressure on the second surface of the ACM, and (ii) the ratio of carbon dioxide to oxygen passing from the first-surface to the second surface of the atmosphere control member (ACM), conventionally abbreviated to “R ratio”, is less than the R ratio of the ACM when the R ratio is measured by the conventionally accepted method in which the pressure difference on either side of the ACM is at a minimum.