All you need to know about Cold Treatment Sterilisation for shipment of fresh produce

Almost all countries around the world import fruit and fresh produce at various stages but fresh produce invariably comes with harmful pests foreign to the importing country potentially putting agricultural activity in that country at risk by their arrival and proliferation..

It may also be the case that the importing country has no effective natural predator of the insects from the origin country and they have to mitigate the potential risk of harmful pests using acceptable measures to ensure phytosanitary imports..

While the risk mitigation measures differ from region to region, country to country, and product to product according to their pest risk management protocols, one of the effective measures for the management of pest risk is Cold Treatment Sterilisation (CTS)..

South Africa is one of the key producers and exporters of citrus, deciduous, avocadoes, pome fruit, and stone fruit to various countries globally..

In this article, reefer logistics industry veteran Andy Connell shares information on all you need to know about Cold Treatment Sterilisation, what it is, how it works, and why it is required..

What is cold treatment sterilisation?

Firstly, Cold Treatment Sterilisation (CTS) is the correct name, but it is also variously, colloquially, and incorrectly termed as Cold Treatment and Steri shipments.

Cold treatment sterilisation is a therapy used to effectively kill any insects in any stage of metamorphosis by providing a lethal dose of cold temperature below 0.0ºC to a consignment of fresh-packed produce.

This therapy requires the consignment core temperature to be uninterrupted for a specific time and the time frame differs based on the fruit and country of import.

For example, for freshly packed citrus fruit exported from South Africa, the period may be from 12 days (Japan) to 24 days (China) or 26 days (EU).

Entomologists will determine the depth of cooling and duration of therapy according the to pest risk profile between the origin and destination regions.

Risk Management Protocols

How is the risk management protocol managed..??

The National Plant Protection Organisation (NPPO) of the destination country will publish their risk management protocols and these may also differ from one supply region to another, according to the risk profile determined between each origin and destination by the destination country.

This is a scientific process whereby pest lists are exchanged (PIP) and researched between both origin and destination. Entomologists evaluate the lists followed by a pest risk analysis (PRA), and then a risk management strategy.

As of 2022, there were 183 NPPOs that are member states of the International Plant Protection Convention (IPPC) and all of them have realised that getting pest eradication is far more costly than preventing the arrival of a pest.

The IPPC is a convention of the Food and Agricultural Organisation (FAO) of the United Nations (UN). The IPPC, in collaboration with all NPPOs, draws up international standards for phytosanitary measures (ISPM) to give firm guidelines on pest risk management in the supply chain.

This phytosanitary process requires the origin NPPO to make a declaration to the destination NPPO that their import conditions have been fully understood and all pest risk management agreements have been met in full.

This is a country-to-country and not an exporter-to-importer process, and the phytosanitary certification process is covered by ISPM 12.

Regulation & Guidelines

Who regulates and provides guidelines for Cold Treatment in South Africa..??

South Africa is fortunate to have the Perishable Products Export Control Board (PPECB) which is an assignee to the Department of Agriculture, Land Reform and Rural Development (DALRRD) – pronounced ‘dalart’ and not ‘dalrid’ (as a few English-speaking people refer to the DALRRD) sic.

The PPECB conducts ongoing research into the cold chain immediately from post-harvest to arrival at the final destination for all fresh packed produce, whether chilled or frozen.

The PPECB regularly updates the cold treatment protocol guidelines (Q25) and this is a single-page document, on the PPECB website with a version number and release date.

The PPECB also draws up and maintains the handling protocols for each of the special markets where cold treatment sterilisation is required.

These step-by-step procedures clearly guide the exporter through the process. Clearing agents regularly fall foul of this and run into trouble because staff refers to a printed document pinned on their desks and often miss the updates.

Exporters of fresh-packed produce refer to this protocol register and find the correct protocol to apply to the type of fruit being exported to the specific destination.

SA fresh produce export process

How does the SA fresh produce export process work..??

The export process is costly, right from the soil and plant material (orchard) preparation, growing treatments, packing treatments, and transport, which all require orchard registrations for the specific market over an above the extra preparation costs.

1. The orchard will undergo an inspection before harvesting may commence.
2. The consignment will undergo a specific inspection for any trace or evidence of the prohibited pests (referred to as ‘vectors’).
   After the inspection process, pallets will be force cooled to the correct transit temperature for the cold treatment sterilisation therapy.
3. Once every pallet has stabilised on the prescribed core temperature of the produce, it can be presented for loading.
4. The refrigerated container (ISO code 45R1) is specially prepared by the container operator (shipping line) and is nominally less than 5 years old (latest generation refrigeration machinery, supple rubber door seals)
5. There will also be three temperature probes (spear probes) hard-wired to the refrigeration control unit to monitor the temp regime).
6. The PPECB pre-trip inspection (PTI) sign-off date in the CY is valid for 30 days for all CTS equipment (containers), whereas for normal chilled cargo, the PTI is valid for 60 days.
7. These probes are calibrated in the releasing container yard (CY) before the release to the exporter.
8. The shipping line will have a representative at each loading, which is supervised by a PPECB inspector who actually places the three spear probes in the prescribed pallets as per the handling protocol.
9. The exporter/shipper should have their own representative present as well, but sadly very few do.
10. The target dwell time is to have each pallet loaded into the conveyance (Container or SRV) within nine to ten days of packing.
11. Some shipping lines require mandatory carrier haulage to ensure their risk is managed by themselves.
12. The trailer will have its own power generator set (genset) to ensure an uninterrupted cold chain along the cross-haul process between the point of packing and the Export stack or intermediate CY
13. The clever exporters pack CTS consignments before the vessel stack opens and places the container into a CY until the stack opens. This allows the three onboard temp spear probes to assimilate the core temperatures and demonstrate the consignment is stable within the required protocol for the therapy to begin. It is far easier to withdraw a container from a CY to unpack and start again.
14. The process of withdrawing a container from the Export stack is a costly and lengthy process requiring the re-import of the container (SARS Bill of Entry voucher of correction)
15. Only once the three spear probes confirm the product is stable at the correct temperature for 24 hours, the container operator presents the PPECB with a data download and the PPECB will issue a pre-cooling certificate (Q98) to the shipping line.
16. The date on the Q98 is the commencement date for the therapy.
17. If the CTS therapy is interrupted by a deviation in temperature, then it must start again.

Some destination NPPOs accept remote temperature monitors placed in the pallets and collect them after arrival to provide provenance of successful CTS Therapy

What is a ‘steri’ failure?

A CTS failure before issuing of the Q98 is a problem solely for the exporter who has clearly not performed to the required standard and involves unpacking the product and starting the precooling all over again.

The falling out of protocol of any of the spear probes after the PPECB has issued the Q98 is a problem the shipping line must shoulder and usually results in a claim.

Countless man-hours and costly management time is wasted because this process is so poorly understood by almost every segment in the supply chain.

Specialised reefer vessels (SRV) are ships built to carry fresh chilled and/or frozen produce.

They nominally have 4 cargo holds with four decks to each hold. (some vessels have only three decks in the front cargo hold)

The cooling plant is very efficient and consistent and provided the voyage transit time exceeds the CTS therapy time, the precooling and CTS therapy can be done once the fruit is actually stowed and ready for departure.

Cold Treatment Sterilisation Success Rate

SRV shipping has a 99.9% success rate while container shipping success rates differ from exporter to exporter.

Some never have a failure, others have serial failures. It all hinges on the level of diligence from plant preparation to shipping.

45R1 reefer equipment, now in its 6th generation of cooling machinery is very rarely the problem.

All CTS therapy consignments are stowed on the first two tiers above the deck where a technician can keep them functioning and online all the time.