Sultana Table Grapes Cold Chain & SO2 Generator Pad Protocols for Overseas Export

# Sultana Table Grapes Cold Chain & SO2 Generator Pad Protocols for Overseas Export Turkish Sultana (Thompson Seedless) table grapes from the fertile Gediz and Büyük Menderes river basins of the Aegean region represent one of the world's most sought-after fresh fruit lines. Characterized by high soluble solids content (18°–22° Brix), delicate golden-green skin, and crisp flesh, Sultana grapes require strict post-harvest protocols to withstand transit times of up to 25 to 30 days without fungal decay or stem browning. ### 1. The Post-Harvest Vulnerability: Botrytis cinerea The primary challenge in overseas grape transit is grey mold caused by *Botrytis cinerea*. Because the fungus can germinate and proliferate at temperatures as low as -0.5°C, temperature management alone is insufficient to protect high-Brix clusters over extended voyages. Continuous, controlled micro-doses of sulfur dioxide (SO2) gas within the carton atmosphere are essential to sterilize fungal spores without causing bleaching or residual sulfur taint. ### 2. Dual-Release SO2 Generator Pad Technology Nilasya Global utilizes laminated dual-release sodium metabisulfite (Na2S2O5) generator pads placed directly on top of packed grapes inside perforated liner bags: - **Fast-Release Phase (First 24–48 Hours):** High initial SO2 emission (approximately 10–15 ppm) immediately eliminates surface conidia and spores inoculated during harvest. - **Slow-Release Phase (Up to 30 Days):** A semi-permeable membrane continuously releases low concentrations (1.5–2.5 ppm) of SO2 triggered by ambient moisture, maintaining an active fungistatic barrier without exceeding European Union MRL limits (10 mg/kg in fruit pulp). ### 3. Precision Pre-Cooling and Pulp Temperature Management 1. **Forced-Air Cooling Tunnels:** Field heat must be extracted within 4 to 6 hours of harvest. Forced-air suction systems rapidly reduce core pulp temperature from 28°C down to 0°C to +1°C. 2. **Transit Setpoint:** Container reefer setpoint is maintained strictly at -0.5°C to 0°C with 90% to 95% relative humidity (RH). Freezing point of high-Brix Sultana grapes is approximately -1.8°C, providing safe thermal buffer while preventing rachis dehydration and rachis browning. ### 4. Aerated Packaging & Airflow Dynamics - **5kg Telescopic Cartons & Plastic Crates:** Designed with 5% side wall ventilation slots aligned with pallet stacking apertures for unobstructed vertical and horizontal cold airflow. - **Micro-Perforated Liners:** 0.3% to 0.5% perforation ratios prevent water condensation pooling on berries while retaining enough relative humidity to activate SO2 release. - **rPET Clamshells and Carry Bags:** 500g and 1kg heat-sealed punnets pre-assembled with individual micro-pad strips for direct supermarket shelf delivery. ### 5. Continuous Cold Chain Monitoring Every container shipped by Nilasya Global includes dual real-time GSM/GPS temperature and relative humidity loggers positioned in the warmest (center) and coldest (door) pallet locations, providing 24/7 visibility to overseas receiving teams.