Overview
Containers used for transporting export perishable products must be absolutely clean to ensure food safety and must maintain optimum temperature and atmosphere conditions to minimize product quality loss. Every aspect of the container handling chain must focus on these two basic requirements. Further details are documented in the PPECB Quality Management System (QMS).
1. Requirements for Container Handling Depots
National and international food safety and traceability legislation, as well as Good Distribution Practices (GDP), are being instituted by the retail trade. All operations associated with the handling and distribution of perishable and food products must comply with approved standards and be open to external auditing.
There are two basic international requirements for the transport of perishable products:
- Prevention of the distribution of quarantine pests
- Protection of cargo against contamination
Key aspects needing attention:
1.1 Stacking Areas
- Storage areas for containers must be well-drained and level.
- Areas must be clean and protected from pollution (chemicals, water, dust).
- A solid or crushed stone (gravel) surface without potholes is a minimum requirement.
1.2 Stacking Heights
- Worker safety dictates stacking heights.
- Single stacking is important for pre-trip procedures, pre-trip inspection (PTI), and cleanliness inspection.
1.3 Repair Bays
- All working areas must comply with national safety requirements.
- Areas must have a concrete floor and be under cover to prevent contamination of exposed insulation.
1.4 Wash Bays
- Wash bays must have a sloped, solid, and permanent surface to allow all wash water to drain away from the container and washing area.
- Wash water must be handled according to local authority rules to avoid environmental pollution.
2. Depot Quality Management Systems
Consumers and international trade are increasingly demanding regarding product quality, food safety, and costs. Due diligence is a basic requirement, and everyone in the food handling and supply chain must accept responsibility for their actions. The only way to comply is to implement and apply a quality management system.
Key aspects to address:
2.1 In-House Quality Control
- All depots handling and preparing containers for export must maintain an in-house quality control system.
- The system must be well documented, personnel well trained, and accurate records kept.
- The system must be internally and externally audited.
- The system must identify and minimize risk areas, demonstrate due diligence, ensure correct container functioning, food safety, and support traceability.
- A thorough container inspection must be done when a used container is delivered to the depot, focusing on:
- Hygiene condition of the container
- Container structure
- Condition of the cooling unit
2.2 Food Safety Requirements
- Authorities of importing countries may stop all imports if there is any suspicion that the product is unsafe or unfit for human consumption.
- Three basic food safety hazards: biological, chemical, and physical contamination.
Management systems must ensure:
- Biological cleanliness: Free from insects, bacteria, fungal spores, and any material that may host contaminants. All surfaces (including air handling systems) must be sterilized. Recontamination after cleaning must be avoided.
- Chemical cleanliness: Free from chemicals, taints, odors, or any substance that may cause chemical contamination. Only approved detergents, sealing compounds, and repair materials/methods may be used.
- Physical cleanliness: Free from objects such as sand, dust, glass, screws, nails, pop rivets, bolts, nuts, or any object that may get into or onto the product. This also applies to the cooling unit and air ducting.
2.3 Traceability Requirements
Traceability is the ability to quickly and correctly trace the origin, handling, storage, transport, and distribution pathways of a product.
In the container context, this means:
- The container’s identification must be known and linked to the consignment at all times.
- The container’s history (previous cargoes, destinations, cleaning, repair, inspection records, storage, and transport conditions) must be known and documented.
- Accurate and detailed records must be available to the exporter, importer, and authorities for each container.
3. Preparation of Integral Refrigerated Containers
The in-house quality control system must identify all structural and mechanical defects and ensure all containers are correctly prepared for perishable products. All containers must have a valid ISO (Paris) registered identification number and a valid safety certificate (CSC plate).
3.1 Structural Maintenance and Repairs
All containers must be inspected for structural and physical defects:
- Container frame must be sound and rust-free.
- External side panels must be dry and not bulge more than 40 mm beyond the steel framework. All joints must be intact and sealed.
- Roof sagging and floor bulging must not exceed 25% (or hinder loading); all joints must be sealed and watertight.
- Doors must not be damaged; hinges and closing mechanisms must operate freely; door seals must be intact and airtight.
- Internal side panels must be intact and securely bonded to insulation. Delamination should not exceed 1m² per side panel (some lines allow up to 25% of a side, if insulation is dry).
- No internal bulging, sharp edges, loose panels, or cargo fixing devices should be present.
- T-bar floor must not be damaged; all joints (especially at the door) must be intact; no floor movement during loading.
- Insulation must be intact and dry. Damaged insulation must be replaced with the same specification.
- All repairs must be made by trained personnel using internationally approved materials and methods. Materials that may give off taints must not be used.
- Repairs and maintenance must be completed and documented before moving the container to the washing bay.
3.2 Cooling Unit – Maintenance and Repairs
All refrigeration units must be inspected for defects, accuracy of control and recording systems, and necessary repairs/adjustments:
- Visual check for damage (loose components, damaged cables/wiring).
- Motor and compressor checked for smooth operation and overheating.
- Oil and gas levels checked and adjusted if necessary.
- Air circulating fans (condenser and evaporator) must operate correctly, with no abnormal noise and correct airflow direction.
- Thermostat temperature controller must be accurately calibrated (±0.5°C from set point). Chill mode is controlled on delivery air; frozen mode on return air.
- Sensors for delivery (DAT) and return (RAT) air temperature must be accurately calibrated and functioning.
- Defrost system must be operational; drain pipe open.
- All indicator lights, fuses, backup batteries, etc., must be fully functional.
- Fresh air ventilation valve must be easy to operate and functioning.
- Air ducts must be unobstructed and clean.
All maintenance must be carried out by qualified personnel to the container owner’s specification. Only specified and approved materials, spares, and components may be used.
3.3 Cleaning of Containers
- Well-designed and constructed wash bays are required, with a solid sloped surface for fast draining.
- The container must be positioned with the door in the lower position.
- All dry material (dust, packaging remains) must be swept or vacuumed.
- All stains must be removed before washing.
- The inside must be thoroughly cleaned (methods: steam cleaning, high-pressure water jets). Only approved detergents may be used.
- All free water, especially in the T-bar floor, must be removed (preferably with high-pressure air).
4. Container Inspection and Storage
Each container must be inspected and approved by PPECB before use for perishable products. PPECB may perform a system audit if the depot demonstrates consistent, reliable operation of an approved Best Operating Practices (BOP) or in-house quality control program.
4.1 Condition and Cleanliness Inspection
- PPECB inspection should be done before the pre-trip (cooling) inspection.
- Aspects to check:
- Valid safety certificate (CSC plate), ISO registration number, and compliance certificate.
- Steel frame must be sound and rust-free; side panels must not bulge outside the steel frame.
- Side panels, roof, and floor must be intact, smooth, sealed, and clean.
- Doors must open/close easily; seals must be intact and airtight; locking mechanism must operate freely.
- Inside must be clean, dry, and free from foreign odor or taint.
- Insulation panels must be clean, intact, dry, and without bulging.
- Max 25% delamination per internal side allowed if insulation is absolutely dry (international recommendation: max 1m² per panel).
- T-bar floor must be in good repair to allow cargo handling and prevent moisture ingress.
- Drain holes must be clean and properly plugged.
- PPECB assessor seals the container doors with a PPECB cleanliness seal after inspection.
4.2 Pre-Trip Inspection (PTI)
Purpose: Ensure correct functioning of the cooling unit and temperature control/recording devices. Two PTI procedures: manual and automatic.
4.2.1 Manual PTI
- Fit a new temperature chart (Partlow) on the recorder before PTI.
- Set thermostat to 0.0°C (chill mode) and -20.0°C (deepfreeze mode).
- Maintain set point temperature within ±0.5°C.
- PTI must be done in both modes if cargo type is unknown.
- Check that at least one defrost cycle occurred and defrost water drained outside.
- Containers for in-transit cold treatment must be set at the specified carrying temperature (usually -1.0°C to 0.0°C) for PTI.
4.2.2 Auto PTI
- Two types: partly automatic (PTI-one, uses Partlow chart) and fully automatic (PTI-two and PTI-three).
- PTI-two: chill mode (0.0°C); PTI-three: deep freeze mode (-20°C).
- Auto PTI process:
- Ignore/remove Partlow chart recorder if fitted.
- Initiate auto PTI-two to allow the microprocessor to check the cooling unit and fans (may take hours).
- Save results and make available to PPECB for verification.
- PPECB verifies container number and that all PTI-two checks are passed.
- PPECB issues a PTI approval sticker if passed.
4.2.3 Temperature Run Method – Microlink
- Some units have a “Microlink” processor.
- Manual PTI or “temperature run” process:
- Set thermostat at 0.0°C (chill) or -20°C (deepfreeze).
- Run cooling unit for ~6 hours (longer for deep freeze).
- Manually check (Partlow chart or electronic download) after ~6 hours to ensure temperature has stabilized at 0.0 ±0.5°C or -20°C or colder.
- At least one defrost cycle must occur during pull down.
- Auto PTI is the same as fully auto PTI (PTI-two and PTI-three). PPECB verifies readings and, if compliant, approves the unit and issues the PTI approval sticker.
Storage of Container
- Approved containers may be stored in the depot for later use.
- PPECB cleanliness and PTI certificates are valid for 60 days, after which both procedures must be repeated.
- Containers must not be damaged or contaminated during storage.
4.3 Setting of Carrying Conditions
- Containers must be set to maintain the carrying conditions specified by the exporter.
- New backup batteries must be fitted to view settings.
4.3.1 Temperature Set Point
- Set required temperature in °C.
- Thermostat must control temperature within ±0.5°C of set point.
- Chilled cargo: control on delivery air.
- Deepfrozen cargo: control on return air.
- Affix a sticker indicating the set point next to the display unit.
- Depot is responsible for correct temperature setting.
4.3.2 Fresh Air Ventilation
- Set the fresh air intake valve according to the booking specification and verified by PPECB.
- Optimum rates are given in Chapter 8.
- Depot is responsible for correct setting.
4.3.3 Controlled Atmosphere (CA) Conditions
- CA requires a gas-tight container and special gas generating/controlling devices.
- Devices must be calibrated and set by depot personnel per shipping line specifications.
4.3.4 Modified Atmosphere (MA) Conditions
- MA conditions are used for specific products/conditions.
- Special generating/controlling devices must be fitted.
- Follow shipping line and MA service provider specifications.
4.3.5 Humidification
- Standard integral refrigerated containers maintain RH of 90±5% at equilibrium.
- Some containers can be fitted with humidity control devices.
- “Humidification” may refer to lower RH (e.g., 70% for bulbs, onions, garlic).
- Higher RH (95–98%) is used for some flowers and leafy vegetables, but >95% may cause condensation and fungal growth.
5. Special Requirements for In-Transit Cold Treatment
Some importing countries (e.g., USA, Japan, South Korea, Taiwan, Israel) require special cold treatments to kill quarantine insects. These requirements are part of bilateral agreements and are regularly updated by PPECB.
5.1 Container Certification
- Container must be specially certified for in-transit cold treatment.
- USA and some countries require a USDA certificate; others require a PPECB certificate.
- PPECB ensures containers comply with:
- Accurate and steady DAT across the air delivery plenum (within 0.5°C of set point).
- Sufficient refrigeration to recool fruit after loading.
- Sufficient capacity to maintain fruit at -0.6°C for at least 22 days.
- Defrost cycle and temperature maintenance to keep fruit pulp at -0.6°C or cooler.
- Cold treatment certificate is valid for 3 years, then must be renewed.
5.2 Temperature Sensors
5.2.1 Air Temperature Sensors
- DAT and RAT sensors must be connected to a permanent onboard data logger with accuracy ±0.1°C at 0.0°C, logging continuously for the full cold treatment (minimum 30 days memory).
- Cargo temperature sensors and data loggers are required (permanent or separate). Only certified systems may be used, calibrated in melting ice at 0.0°C by PPECB before each cold treatment.
- Some countries require 3, others 4, cargo temperature sensors, placed in specified fruit positions by PPECB. Accuracy must be ±0.1°C at 0.0°C. Log at least once per hour in 0.1°C units.
5.2.2 Calibration of Temperature Loggers
- Both permanent and separate loggers must be calibrated by PPECB before loading.
- Total accuracy (sensor, cable, logger) must be less than ±0.25°C.
- See Chapter 2 par 4.3.3 for more detail.
5.3 Precooling of the Container
- Containers for in-transit cold treatment must be set at the specified temperature and precooled for at least 6 hours before loading.
- Some countries require only precooled containers be loaded (containers must be on cooling until ready for loading).
6. Predispatch Check
All containers for export of perishable products must be checked before leaving the depot (gate out check).
6.1 Container Transport Documents
- A container terminal order (CTO) for port area loading or a container transport document (TPD) for inland loading must be delivered to the depot.
- All necessary information and container settings must be specified.
- Depot must verify all information and ensure:
- Correct temperature set point
- Correct fresh air ventilation setting
- Correct CA settings if required
- All necessary additional controlling and recording devices are installed
Notes:
- Only original and unchanged transport documents are acceptable.
- Incorrect containers, containers with incorrect settings, or containers not accompanied by a transport document (or with a changed document) shall not be loaded and will be returned to the depot at the depot’s cost.
6.2 PPECB Seals
Only containers with valid PPECB seals (certifying compliance to cleanliness and PTI specifications) may leave the depot.
7. Containers for Ventilated Transport
Ventilated transport and shipment of certain perishable products can only be done under specific conditions, with certain equipment, and to certain destinations. Main problems include:
- High humidity at sea (especially fog) and large day/night temperature fluctuations (notably on the West Coast of Africa) can cause condensation on the product and packaging.
- Rain and seawater can enter the container and cause damage.
- Delays in departures and transshipments can result in extended storage, risking rejection if the maximum permissible voyage is exceeded.
7.1 Types of Ventilated Containers and Specific Requirements
7.1.1 Open Door Containers
- Standard General Purpose (GP) containers are used for open door shipments.
- Doors must be kept open except during rain or high seas.
- Tarpaulins must cover the door opening when rain is expected.
- A system to secure cargo from moving must be installed.
- Prescribed cargo packaging and loading procedures must be followed.
Open door containers must:
- Have a valid ISO identification number
- Have a valid safety certificate (CSC plate)
- Be sound and rust-free with all load-bearing surfaces in good condition
- Be clean, dry, free from taint, and pass a PPECB cleanliness inspection at least 24 hours before loading
- Have a cargo securing system (e.g., hooks at the door end)
7.1.2 Open Side Containers
- The long side of a standard GP container is removed, with additional strengthening structures and a galvanized steel screen.
- Doors must be closed; fresh air circulates along the container’s length.
- Tarpaulins must be fitted to prevent rain and seawater entry.
- Same requirements as open door containers apply.
7.1.3 Fan or Ventainers
- Insulated or standard GP containers with an extraction fan to actively circulate air through the load.
- The fan may be permanent (in the bulkhead) or loose (fitted between doors).
- Air must be continuously and actively sucked through the load.
- Same requirements as open door containers apply, except tarpaulins are not required.
7.1.4 Passive Ventilated Containers
- Fitted with covered air vents on both long sides at the bottom and top.
- Allow convection flow of air on the inner sides.
- Not suitable for shipment of perishable products.
7.1.5 Flat Racks
- Flat steel structures of the same horizontal dimensions as a 12-meter (40ft) container.
- Cargo is loaded directly onto the steel base and secured by wire mesh or tarpaulins.
- Not readily available for South African trade but can be used for ventilated cargo.