Abstract
Strawberries are extremely perishable due to their susceptibility to decay, softening, and water loss. Rapid establishment of a modified atmosphere (MA) with elevated CO[sub2] is considered to be critical for long distance strawberry shipments in order to inhibit these negative changes, especially decay. However, passive MA systems that may be used for strawberries develop the target atmosphere slowly. We stored 'Camarosa' strawberries for 10 days in a closed system at 2 ordm;C with the strawberry weight:void volume ratio chosen to simulate transport in a 40-foot marine container. An atmosphere of 5% O[sub2] plus 5% CO[sub2] developed in the MA after 10 days and appeared to delay fruit senescence and prevent microbial growth. However, sharp increases in respiration rate and the respiratory quotient beginning on day 8 of storage in MA indicated the initiation of fermentative metabolism. After 10 days in air or MA, the strawberries appeared normal, but after an additional 12 hours at room temperature there was significant microbial growth on the air-stored fruit, which may have been due to latent infections that couldn't be expressed at 2 ordm;C. These results indicate that 5% O[sub2] plus 15% CO[sub2], although commonly used for domestic strawberry shipments, may not be appropriate for transit times longer than 7 days. It appears that about 9 to 10% O[sub2] plus 10 to 11% CO[sub2] may be a better gas composition for transit times greater than 7 days since the strawberry respiration rate was at a minimum in that atmosphere range.
