Cold Chain Packing SOP: Best Practices for Fresh Produce Exports

Maintaining cold chain integrity is critical when shipping fresh produce. A single break in the temperature chain can result in spoilage, quality degradation, and significant financial losses. This SOP outlines best practices for packing fresh produce for international shipment.

Understanding the Cold Chain

The cold chain is the unbroken series of refrigerated production, storage, and distribution activities that maintain a desired low-temperature range. For fresh produce, this typically means:

• Fruits: 0°C to 13°C (depending on variety)
• Vegetables: 0°C to 10°C (depending on variety)
• Never frozen (unless specifically intended)

Temperature Requirements by Product

Product Category	Optimal Temp (°C)	Relative Humidity
Apples, Pears	0 to 1	90-95%
Citrus	5 to 8	85-90%
Tropical Fruits	10 to 13	85-95%
Berries	0 to 2	90-95%
Leafy Vegetables	0 to 2	95-100%
Tomatoes	10 to 12	85-90%

Pre-Packing Requirements

1. Product Selection

• Only pack produce meeting export quality standards
• Remove damaged, diseased, or overripe items
• Ensure products are at the correct maturity stage
• Verify product is free from pests and contamination

2. Pre-Cooling

Pre-cooling is essential before packing. Methods include:

Forced Air Cooling

• Most common for fruits and vegetables
• Air is pulled through stacked produce
• Can reduce temperature in 1-6 hours

Hydro-Cooling

• Immersion in cold water
• Suitable for products that tolerate water contact
• Very fast cooling (minutes)

Room Cooling

• Placing produce in a cold room
• Slowest method (12-24 hours)
• Suitable for hardy products

Target: Reduce product to shipping temperature before packing.

3. Pre-Cooling Verification

Before packing, verify:

• Pulp temperature (use probe thermometer)
• Core temperature for large items
• Document readings for traceability

Packing Materials

Cartons and Boxes

Specifications:

• Food-grade corrugated cardboard
• Wax-coated or moisture-resistant for high humidity
• Adequate ventilation holes (5-8% of surface area)
• Stackable with sufficient crush strength
• Clean and pest-free

Sizing:

• Maximum weight: 10-15 kg per carton
• Standard export sizes for palletization
• Consider destination handling requirements

Inner Packaging

Liners:

• Modified Atmosphere Packaging (MAP) bags for extended shelf life
• Perforated polyethylene for humidity control
• Absorbent pads for excess moisture

Cushioning:

• Foam nets for individual fruit protection
• Molded pulp trays for layer separation
• Paper shreds for filling void spaces

Labeling Requirements

Each carton must display:

• Product name and variety
• Net weight and count
• Country of origin
• Producer/packer identification
• Lot/batch number for traceability
• Grade/class
• Best before date (if applicable)
• Storage temperature instructions

Packing Procedure

Step 1: Workstation Preparation

1. Clean and sanitize packing tables
2. Ensure cold room is at operating temperature
3. Stage all packing materials
4. Calibrate scales and temperature probes
5. Brief packing team on quality requirements

Step 2: Quality Inspection

1. Visually inspect incoming produce
2. Check pulp temperature (reject if above target)
3. Remove any non-conforming items
4. Document inspection findings

Step 3: Packing

1. Line carton with appropriate liner/pad
2. Place produce gently to avoid bruising
3. Arrange in single layer or with separators
4. Ensure even weight distribution
5. Do not over-pack (allow for airflow)
6. Apply top liner/cushioning
7. Close carton securely

Step 4: Weighing and Labeling

1. Weigh packed carton
2. Verify weight meets specifications
3. Apply pre-printed label
4. Add lot number and pack date
5. Place on designated pallet location

Step 5: Palletization

1. Use clean, pest-free pallets
2. Stack cartons in stable pattern
3. Ensure ventilation between cartons
4. Maximum stack height per product spec
5. Secure with strapping or stretch wrap
6. Apply pallet labels

Quality Control Checks

During Packing

Check	Frequency	Action if Failed
Product temperature	Every 30 min	Stop packing, re-cool
Carton weight	Every 10th carton	Adjust fill level
Visual quality	Continuous	Segregate defects
Label accuracy	Every pallet	Correct and reapply

Pre-Loading Inspection

Before loading into reefer container:

1. Verify all documentation complete
2. Check container pre-cooling (probe temp)
3. Inspect container cleanliness
4. Verify temperature set-point
5. Confirm ventilation settings
6. Document with photographs

Reefer Container Loading

Container Preparation

1. Pre-cool container to shipping temperature
2. Inspect for cleanliness and odors
3. Check seals and refrigeration unit operation
4. Place temperature loggers

Loading Protocol

1. Load quickly to minimize temperature rise
2. Stack pallets with T-bar airflow channels
3. Leave space at front for air circulation
4. Do not block return air vents
5. Ensure stable stacking (no movement during transit)
6. Close doors promptly after loading

Post-Loading

1. Set temperature and ventilation per product requirement
2. Record container number, seal numbers
3. Document set-point and actual temperature
4. Take photos of loaded container
5. Initiate temperature monitoring

Temperature Monitoring

Logger Placement

Place temperature loggers:

• Near the door (warmest area)
• In the center of the load
• Near the refrigeration unit (coldest area)

Monitoring Frequency

• Real-time monitoring preferred (IoT devices)
• Or data loggers with 15-minute intervals
• Review temperature data upon arrival

Alert Thresholds

Set alerts for:

• Temperature exceeding set-point by 2°C
• Rapid temperature changes
• Refrigeration unit malfunction

Documentation Requirements

Maintain records for each shipment:

1. Packing Records

   • Date and time of packing
   • Lot numbers packed
   • Quantity and weights
   • Quality inspection results
   • Pre-cooling temperatures

2. Loading Records

   • Container number
   • Loading date and time
   • Seal numbers
   • Temperature set-point
   • Logger serial numbers

3. Certificates

   • Phytosanitary certificate
   • Packing list
   • Health certificates (if required)
   • Cold treatment certificate (if required)

Troubleshooting Common Issues

Temperature Excursion

If temperature rises above threshold:

1. Check refrigeration unit operation
2. Verify ventilation settings
3. Assess if pre-cooling was adequate
4. Document excursion duration and peak
5. Notify recipient for receiving inspection

Quality Issues at Destination

Investigation checklist:

• Review temperature log data
• Check transit duration
• Assess handling at transship points
• Review packing compliance
• Evaluate product maturity at packing

Continuous Improvement

After each shipment, review:

• Arrival quality reports
• Temperature data analysis
• Customer feedback
• Any claims or rejections

Use findings to improve:

• Packing procedures
• Temperature targets
• Material specifications
• Supplier quality

How Element3 Supports Your Cold Chain

Our TradeOS™ platform includes:

• Real-time temperature monitoring integration
• Automated alert systems
• Digital documentation management
• Quality tracking and analytics
• Supplier performance scoring

Contact us to learn how we can help optimize your cold chain operations.