Best Practice Guidelines: Golden Delicious (2020)

1. Variety Selections

Panorama Goldens / Early Goldens & Golden Delicious

2. Harvest Maturity

2.1. Picking Windows

• The picking window can be divided into three periods: pre-optimum, optimum, and post-optimum.
• Pre-optimum (first 3–4 days after release): Good storage potential, but taste develops during/after storage. Risk of superficial scald and bitter pit. Long storage may cause shrivelling.
• Optimum (middle 7–10 days): Best for medium (±4–5 months) to long (±6 months+) storage and better taste.
• Post-optimum: Short (±2–3 months) storage potential but superior taste. Overmature fruit risk greasiness, mealiness, internal browning, decay, yellowing, and bruising.
• Fruit picked before optimum maturity is more prone to bitter pit.

2.2. Maturity Criteria

• Reference: Pome fruit protocols: Picking, Storage requirements for Sea Export of Pome fruit (ppecb.com)
• Record if fruit was treated with Retain or Harvista.
• Store fruit with different maturity separately in CA conditions.
• Identify and handle risky orchards differently (e.g., young orchards, history of bitter pit, low crop load/big fruit).

3. Bin Type & Bin Conditions

• Use rigid, smooth, clean, thick-bottom bins (wood or plastic) to minimize bruising.
• About one-third of apples in a bin contact the bottom or sidewalls.
• Bins must be clean (dust-free and free of rotten fruit) to prevent rub marks, bruising, and decay. Clean with sanitising agents.

4. Post-Harvest Drench

4.1. Increasing Calcium Content (Optional)

• Bitter pit is correlated with fruit size, tree vigour, fruit N, K, Mg; develops where calcium is inadequate.
• Dipping in calcium chloride or nitrate increases near-surface calcium. Seldom needed if orchard factors are optimal and enough calcium sprays were applied.
• Side effects: blemishing (calcium spot), lenticel damage.
• Drench as soon as possible after picking. Do not drench if fruit temperature is ≥25°C (risk of lenticel burn).
• If drenched with water, ensure water is sanitised.

4.2. Sanitization (Optional)

• Calcium hypochlorite at 75–100 ppm can be used for sanitization.
• Adjust concentration per cultivar: e.g., Red and Granny’s 0.75%, Goldens and sensitive cultivars 0.5% calcium (not solution).
• At label concentrations.
• Letting fruit stand overnight increases bitter pit risk.

5. Decay Control (Optional)

• Fludioxonil (Scholar/Teacher) or Pyrimethanil (Protector) can be used for decay prevention.
• Optional for long-term CA storage.
• Follow label instructions for dilution.

6. Bin Intake

• Do not leave fruit outside overnight. Place under cooling as soon as possible; minimize temperature breaks.
• Consider harvest maturity when loading CA rooms.

• Take a representative sample size: suggested 10 fruit for starch and 10 for pressure/sugar per PUC per orchard per intake.

7. Inspection

• Post-packing inspections per exporter or DALRRD minimum export standards (www.dalrrd.gov.za).
• Arrange with PPECB for regular inspections to enable forced-air cooling ASAP.
• Approved pallets must be in a cold room for forced-air cooling within 1 hour after inspection.
• Conduct shelf-life analyses for progressive defects (e.g., bitter pit). Keep fruit at 22–24°C and test on days 3, 5, 7, and 10.

8. Cooling Protocol

• Maintain pulp temperature between -0.5°C and +0.5°C at all times.
• Pallets: forced air cooling setpoint -1°C until pulp core temperature is reached.
• DAT (Delivery Air Temperature): down to -2.3°C (summer) or -1.7°C (winter) if ambient is warm/cool.
• Pallets in holding room at setpoint -0.5°C; DAT can go down to -1°C.
• Use good temperature monitoring.

9. RA Period

• Panorama Golden: Pack by Week 11 for export.
• Golden Delicious: Pack by Week 12 for export; if Smartfresh treated, pack by Week 15.

10. Pre-Sorting Protocol

• Wait at least 3–5 days before pre-sorting to avoid bruising.
• Load within 7 days from opening and pre-sorting out of a CA room.
• Pre-sorted bins should return to cold store within 40–60 minutes from filling.

11. Storage Regimes

11.1. Regular Atmosphere Storage (RA)

• Fruit should reach pulp temperatures of -0.5°C within 48 hours of harvest and be held at that temperature.
• Set-point temperature should never be lower than -1°C.

11.2. Controlled Atmosphere Storage (CA)

• Cool rooms 24–48 hours before loading.
• Stack rooms per CA floor plan for effective cooling.
• Do not exceed daily cooling capacity.
• Do not apply CA conditions until fruit pulp temperature is at/below 3°C.
• CA room loading within 7 days of harvest.
• If Smartfresh treated, must be done within 14 days of harvest (protocol: 7 days from start of loading).
• Within 7 days after closing, CA conditions should be reached.
• Relative Humidity: 90–95%.
• Measure ethylene levels every 2 weeks in CA rooms.

11.3. Recommended CA Conditions

• Reference: CA Manual Revised (2019), ARC Infruitec-Nietvoorbij

11.4. 1-MCP Treatment

• 1-MCP (Smartfresh and others) slows ripening and ethylene production.
• The sooner after harvest, the better for fruit quality. If room not filled within 7 days, dual application is needed.
• Vents must be open and rooms ventilated to prevent CO₂/ethylene build-up before 1-MCP treatment. Flush with fresh air if closed for days.
• Store at +2°C (DAT) before/during 1-MCP treatment. Change setpoint after treatment.

12. Moisture Loss (Shrivelling)

• Reduce moisture loss by:
  • Never leaving bins outside for extended periods.
  • Starting cooling ASAP after delivery.
  • Using 4-way bins for better airflow.
  • Using one bin type per room/row.
  • Covering CA store floors with water or using humidifiers.

13. Wilting

• Use John Findley’s cold wilting process (see CA Manual) when opening a CA room.
• Do not wilt at ambient temperature—causes stress and man-made bitter pit.

14. Packing Preferences

14.1. Controlling Bruising

• Golden Delicious is very bruise-prone, especially as maturity increases.
• Soil moisture, rain, and dew increase bruise risk.
• Momentum (mass x velocity) and kinetic energy are major drivers for bruises.

General Guidelines

• Implement quality control/monitoring from picking through transport and packing.
• Train quality controllers and sample fruit regularly for bruising.
• Use electronic apples to identify machinery damage points.
• Continuous training and discipline are essential.

Receiving Fruit Bins & Dispatch of Pallets

• Train forklift operators.
• Travel slowly and handle bins/pallets gently.
• Use full-length forks.
• Proper container loading to avoid force on last pallet.
• Train trolley jack operators.

Sorting

• Handle fruit gently; avoid excessive handling.
• Provide sufficient lighting and use white/silver sorting belts.

Packing

• Monitor packers; one fruit per hand only.
• Close carton lids gently (corners, not middle).
• Place cartons gently on conveyor; use elevators where available.
• Do not overfill packing tables.

Bagging

• Use rubber-padded platforms.
• Do not throw or drop fruit into bags.
• Place bags correctly in cartons; fruit should not press directly against each other.

Packing Line Machinery

• Ensure singulator/sizer timing and synchronization.
• Run lines at slower speeds to minimize bruising.
• Eliminate unnecessary drops/turns; reduce drop heights.
• Pad all drops and use curtains to slow fruit.
• Suspend conveyor belts at drops.
• Place drop boards correctly to avoid pinching fruit.

Palletising

• Place cartons gently on pallets; use ladders/jacks for top layers.
• Avoid overfilling bins at pre-sorting.

14.2. Packaging Types

• Packaging should allow sufficient cooling, maintain colour, prevent defects, and prevent bruising.

Carton Design

• Sufficient ventilation is crucial for pre-cooling and cold chain maintenance.
• Airflow must be both horizontal (pre-cooling) and vertical (reefer containers/vessels).
• At least 5% of carton bottom surface should be open for airflow.
• Super Vent designs are recommended.
• Inner packing material (especially plastic bags) often blocks ventilation holes—consider this in pre-cooling/container temperature regimes.

Plastic Bags

• Used to maintain colour and humidity, increase CO₂ (reduces bitter pit and yellowing), and act as a “cool bag” in poor cold chains.
• Thickness:
  • MK9 – 20 micron (mainly humidity barrier)
  • MK4 – 37 micron (normal cold chains)
  • MK4 – 65 micron (poor cold chains)

15. Logistics

15.1. Optimum Shipping Conditions

• Temperature: -0.5°C
• Relative Humidity: 90–95%
• Vents closed (prevents tropical air ingress and excess defrost cycles)

• First weeks Panorama: load at 0°C. If TSS >13, ship at -1°C (D1, also for Goldens).
• Nigerian/African ports: Loadshedding and intermittent cooling can cause up to 8-day delays. Clarify responsibility with insurer. Use cell phone-enabled temperature loggers in containers.

16. References

• Bruising and its control – Finlay
• Pome fruit protocols: Picking, Storage & Handling (HortGro)
• DFPT Research Bitter Pit Pamphlet
• CA Manual Revised (2019)
• Pome Fruit Packaging Guidelines
• Basic Cooling Guidelines for Pome Fruit
• HP28 Handling Procedure and Optimum Temperatures for Sea Exports of Pome Fruit (www.ppecb.com)
• HP22 Temperature Regimes
• PPECB Blue Book