Cold Chain for Bangladesh’s Lychee (Litchi) Export: Why Speed Matters More Than Temperature

Lychee is one of the least forgiving fruits in Bangladesh’s export basket. Grown mainly around Dinajpur and parts of Rajshahi, the harvest window lasts only a few weeks in late May and June, and the fruit’s shelf life at ambient temperature is measured in days, not weeks. Unlike mango or jackfruit, where a delay in cold chain mostly costs you ripeness and firmness, a delay with lychee shows up almost immediately as browning skin on fruit that is often still perfectly fine to eat underneath. That gap between what the fruit looks like and what it actually is has cost Bangladeshi exporters shipments that were rejected on appearance alone, which makes lychee one of the clearest cases where cold chain speed, not just cold chain existence, decides whether an export shipment succeeds.

The Browning Problem Is Cosmetic, and That Makes It Worse

Lychee’s red skin colour comes from anthocyanin pigments in the pericarp, and those pigments break down through enzymatic browning and moisture loss within 24 to 48 hours at room temperature in Bangladesh’s humid pre-monsoon heat. The flesh inside is often unaffected at the point the skin has already turned brown and blotchy, but buyers judge lychee on skin colour before anything else, so a fruit that is objectively fine gets rejected on sight. This is different from most produce cold chain problems, where poor handling shows up as actual decay. With lychee, poor handling shows up as a fruit that looks spoiled well before it is, which means the fruit has to be cooled fast enough that the browning process never really gets started.

Pre-Cooling Has to Happen Within Hours, Not Overnight

Field heat is the enemy here. Lychee harvested in the late morning in Dinajpur’s pre-monsoon heat can sit at 30–35°C, and every hour it stays at that temperature before cooling accelerates both moisture loss and browning. Forced-air cooling, where chilled air is pulled directly through stacked crates rather than just circulated around a cold room, brings fruit temperature down far faster than simply placing crates in a walk-in cold store and waiting for ambient cooling to work through the stack. The target is generally to get fruit down to somewhere around 3–5°C within a few hours of harvest, and the practical reality for most Bangladeshi growers is that this requires a pack house or pre-cooling point close to the orchard, not a cold store that is an hour or more away by road.

Treatments Used Internationally, and Where Honesty Matters

Major lychee exporting countries like Vietnam, China and Madagascar commonly use a combination of sulfur dioxide fumigation and an acid dip (often citric or hydrochloric-based) immediately after harvest to slow pericarp browning during the export window, sometimes followed by a light sulfite residue that gives the fruit its characteristic pale look on some export markets. We are not going to give you a specific protocol here, because the correct treatment, permitted chemicals and residue limits depend entirely on the destination market’s food safety rules, and getting this wrong risks a shipment rejection for entirely different reasons than browning. If you are pursuing formal lychee export, this is a conversation to have with a food safety consultant or the receiving market’s import authority before harvest, not something to improvise at the pack house.

Packaging That Actually Slows the Clock

Ventilated plastic crates lined with perforated polyethylene bags are the standard combination for lychee, because the bag holds humidity around the fruit (reducing moisture loss) while the perforations let some respiration gas exchange happen so the fruit does not suffocate in its own carbon dioxide. Packing too tightly, or stacking crates without airflow channels between them, traps heat inside the pallet even inside a cold room, creating warm pockets that brown faster than the rest of the load. For fruit destined for air freight, weight matters as much as protection, since lychee is usually shipped by air given its short shelf life, and every kilogram of packaging cuts into the chargeable weight the exporter is paying for.

Cold Chain From Orchard to Airport

A realistic lychee export cold chain in Bangladesh runs through several handoffs: pre-cooling near the orchard, a refrigerated vehicle to a pack house or consolidation point, cold storage while the shipment is built up to a viable air freight volume, and then airport handling that ideally keeps the fruit in a temperature-controlled area rather than sitting on the tarmac. Each handoff is a chance for the cold chain to break, and because lychee’s tolerance for a broken cold chain is so low compared with hardier fruit, even a single two-hour gap in an un-cooled vehicle can visibly affect the final product. This is why lychee export has stayed a smaller, more specialised trade compared with mango or jackfruit — the infrastructure required per kilogram shipped is genuinely higher.

What This Means If You Are Starting Small

Not every grower or trader needs full pre-cooling infrastructure to benefit from better cold chain practice. Even without forced-air cooling, moving lychee into any available shaded, ventilated cold storage within an hour or two of harvest, rather than letting it sit in open baskets in the sun while transport is arranged, measurably slows the browning clock. For traders supplying the domestic market rather than export, a mini cold storage unit sized for short-term holding — a day or two, not weeks — can be the difference between fruit that reaches Dhaka wholesale markets looking sellable and fruit that has already started to brown by the time it arrives.

• Field heat is the first and biggest quality loss point — cool within hours, not by end of day.
• Browning is a cosmetic clock, not a spoilage clock, but buyers cannot tell the difference by looking.
• Ventilated packaging with a humidity-retaining liner beats either loose crates or fully sealed bags.
• Chemical browning-control treatments are destination-market-specific — do not guess, ask before you need to.
• Every un-cooled handoff between orchard and buyer costs shelf life you cannot get back later.

Domestic Trade vs True Export-Grade Infrastructure

It is worth being clear-eyed about scale here. Most lychee moving through Bangladesh today travels through domestic wholesale channels — Dinajpur and Rajshahi growers selling into Dhaka’s Karwan Bazar and other wholesale markets, a journey of hours rather than days. That trade benefits enormously from even modest cold chain improvements: a few hours of pre-cooling and a refrigerated rather than open-bed truck can be the difference between fruit that reaches Dhaka looking sellable and fruit that has already browned in transit. Formal international export is a different proposition entirely, requiring forced-air cooling infrastructure, potentially fumigation or treatment facilities, phytosanitary certification, and air freight capacity timed precisely against a harvest window measured in weeks. A grower or trader deciding where to invest should be honest about which market they are actually serving — the equipment and infrastructure needed to supply Dhaka reliably is a fraction of what true export requires, and conflating the two leads to either underinvestment for export ambitions or overinvestment for what is really a domestic supply chain.

DE International supports Bangladeshi agricultural exporters and traders with cold chain equipment sourcing from China, including forced-air pre-cooling units, refrigerated transport solutions and pack house cold storage sized for fast-turnover fruit like lychee. If your business is scoping cold chain infrastructure for a short, intense harvest season, our sourcing and logistics services can help you specify the right equipment rather than over-building for the wrong kind of storage. See also our guides on pre-cooling methods for fresh produce and cold chain for mango export. Reach us through our contact page or browse the shop for sourcing options.