Dr. Prange did a recent presentation on the management of
CO2 levels in apple and pear CA storage. Watch the presentation here: https://youtu.be/Cq4x3zFvRzc
Key Summary:
– Too much CO2 can cause external and internal fruit damage.
– Avoiding CO2 damage will depend on: Cultivar, Oxygen concentration, Stage in
storage season, Storage temperature, Storage humidity, Use of post-harvest
chemicals – 1-MCP, DPA.
– Timing Matters: High CO2 at the beginning of storage is more damaging than later in
storage.
– Post-harvest chemical influence: The CO2/O2 ratio in CA is lower if 1-MCP is used
while DPA can reduce CO2 damage.
Final Considerations:
– If no history of CO2 damage – maintain current practices.
– If there is a history of CO2 damage, consider one or more of the following:
o Scrub CO2 during loading and cooling, e.g., activated carbon and/or lime
o Scrub CO2 during O2 pull-down.
o In CA, control CO2 levels according to the CO2/O2 ratio for a specific cultivar.
o Consider scrubbing CO2 for the first few weeks of CA. i.e. 4 weeks.
o There is evidence that cultivars that tolerate high CO2/O2 ratios may lose
their CO2 tolerance at chilling temperatures, i.e., < 1.0 ºC.
o In DCA (<1 kPa O2), there is evidence that the CO2/O2 ratio can be higher.
o If 1-MCP is applied at beginning of storage – reduce CO2 by ca. 50%
o If DPA is allowed – it may reduce risk of CO2 damage
