Firmness is one of the quality parameters used to define
freshness in horticultural crops. Firmness is related to gas
composition. Decreased softness in fresh produce has been
reported when exposed to high levels of CO2. According to
Harb and Streif (2004), ‘Duke’ blueberries stored in 6–12%
CO2 maintained their firmness at acceptable values. In the
present study, ‘Elliott’ blueberries maintained their plumpness
during 18 days storage (data not shown) even when
exposed to levels of CO2 less than 6% (Fig. 2). Blueberries
packed in clamshells containers had became soft a few days
after packaging (data not shown).