Question
Looking for some information on the storage of fresh dates, I found your recommendations for maintaining postharvest quality. I have just a few additional questions (I understand that answers depend on the cultivar, but I will be happy with general answers if possible.) 1. What is the recommended temperature for fresh dates (0 ºC?) and how long can dates be stored at these conditions? 2. Is there any additional advantage of low oxygen in terms of storage duration (apart from prevention of darkening of the colour) 3. What about carbon dioxide in this respect? 4. Does harvest date modify these characteristics significantly? I would be very happy if you could answer these questions briefly and/or give me a literature reference .Thanking you in advance! (A.dJ.)
Answer
Semi-soft date cultivars (such as Deglet Noor, Halawy, and Zahidi) can be stored at 0C for up to one year vs. 8 months at 4C vs. 3 months at 15C vs. one month at 21C. Soft date cultivars (such as Medjool, Barhee, Khadrawy, and Maktoom) can be stored for about half the duration of semi-soft dates (6 months at 0C, etc). In all cases, relative humidity should be 70-75% (equilibrium relative humidity). All date cultivars can be kept at -18C for one year or longer. Low oxygen atmospheres (less than 1%) can be useful in control of insect growth and activity in addition to maintaining quality of the dates. Fumigation with carbon dioxide for 24 hours or freezing and storage at -18C for 2 days or longer can be used for insect control in organic dates, when methyl bromide fumigation may not be allowed. Harvest date after the dates have reached full ripeness (tamar stage) does not affect these recommendations, but delays in harvesting may expose the dates to unfavorable environmental conditions that encourage insect infestation and fungal infection. Also, moisture content of the dates may decrease or increase depending on ambient relative humidity and temperature during the time the dates remain on the palm tree.
–Adel Kader.