Post harvest drenches and chemical treatments
Many pack houses drench incoming fruit with a 50 to 100 ppm chlorine drench as a
phytosanitary measure to reduce decay potential during storage. Golden Delicious or Braeburn
apples which are susceptible to bitter pit or lenticel spot may be subjected to a calcium drench
such as calcium chloride or commercially available products such as Calcimax® or Stopit®.
Granny Smith, Pink Lady® brand, Golden Delicious and some of the Red cultivars are prone to
superficial scald and so are treated with diphenylamine (DPA) ranging from 1500 to 2500 ppm
depending of the cultivar and the harvest maturity of the fruit. In some instances, yeast and
Rovral® are added to the drench as a means of reducing decay potential during storage.
SmartFresh™ a new post harvest application is currently benefiting the South African apple
industry. Due to its ethylene blocking effect, SmartFresh™ maintains the quality of fresh
produce during extended cold storage and shelf life. SmartFresh™ is applied to the fruit within
seven days of harvest in an airtight cold store. Adding water to a soluble powder releases the
active ingredient, which is fully distributed throughout the room within two hours. The fruit can
be mixed with untreated fruit or moved to another cold store after the 24 hour treatment.