Product handling protocols for genus Protea
Harvesting stage should be Soft tip for both air freight and sea freight picked flowers. Open flowers can be picked for air freight.
Harvesting time can be any time of the day with varieties that are not prone to leaf blackening. The varieties that are sensitive to leaf blackening can be picked at any time of the day if they are pulsed. If these varieties are not being pulsed afternoon picking is best.
Leaf blackening is a complex problem. Growers need to determine the best and most practical method of glucose application for their situation. Ideally flowers should be picked dry, put into the pack shed or shaded area as soon as possible and then pulsed. A concentration of 10% glucose (1kg per 10 litre water) will not cause toxicity as long as not more than 10ml of glucose is taken up per stem. Uptake should take place within the first 2 hours of picking. Water pH also plays a role.
Harvesting conditions should be dry. Products should be hydrated and cooled as soon as possible, especially in warmer conditions. Products should be pre-cooled to between +15°C to +20°C after harvesting.
Superstack cartons should be used to prevent collapsing of bottom layers of palletised product.
If the cold chain is going to be maintained from the farm then start the cold chain on the farm. If not then pre-cool products on the farm to +15°C to prevent condensation. All product should be cooled on the farm or at the depot within 6 hours after packing, via forced air cooling or vacuum cooling. Static cooling inside cold room is not effective. Forced cooling should be discontinued when product temperature reaches +2°C to +3°C and allow static cooling thereafter.
Adapted from PPSA product handling table: www.ppsa.co.za.