Fruit flies, humidity and customs rejection: an export packaging guide
Fruit fly, wet cartons and paperwork are three different failures. Only one of them is decided by your pallet wrap.
Three different failures all get called a customs problem
When an export load is stopped, the reason is usually one of three things, and they have little to do with one another. A plant health finding — a live pest, a soil trace, an intercepted consignment. A documentation failure — a certificate missing, out of date, or not matching the goods. Or a condition failure: the pallet arrives wet, mouldy or leaning and is refused on sight.
Packaging decides the third one. It has no vote at all in the second, and only an indirect part in the first. Anyone who tells you a film will get your consignment across a border is selling something they cannot deliver. What follows is the honest split, so you spend money and attention where they change the outcome.
What packaging can and cannot do about fruit fly
A stretch wrap is not an insect screen, and no perforated film should be sold as one. Quarantine pests are managed where they are genuinely controlled: in the orchard and the field, in packhouse hygiene and grading, in the primary packaging around the product, and in whatever approved treatment and temperature regime the destination requires. That is where the effort belongs.
What the wrap can do is avoid making it worse. A load held warm and humid under a sealed film breaks down faster, and breaking-down fruit is what attracts flies in the yard at both ends and what makes a consignment worth a closer look. Ventilation and a cool, dry pallet are a hygiene measure. They are not a pest barrier and should never be described as one.
If a treatment is part of your protocol — a temperature regime in transit, or anything applied to the pallet — ask your inspector and your importer whether the wrap you intend to use is compatible with it. Some regimes need air to reach the product; some need the load presentable for inspection. A film supplier cannot answer that for your destination.
Humidity is the failure you can actually engineer out
This part is genuinely yours to fix. Produce respires after harvest, giving off heat, carbon dioxide and water vapour for as long as it is alive. Seal that under a solid film and humidity inside the wrap climbs until the film's inner face drops below the dew point of the trapped air. Water forms there and runs back onto the cases.
The result is exactly what gets refused: softened corrugated that no longer carries the stack, a leaning pallet, lifted labels and unreadable print, and mould that only needs a warm damp corner and a few days at sea. None of it is visible when the truck leaves. All of it is visible when the pallet is opened.
Aerosonic answers that mechanism — a macro-perforated pallet wrap whose hole size and perforation count are set against the load, so respiration heat and vapour leave the pallet and cold air reaches the cases in the middle of the stack. In Toreto's own August 2026 wrap tests, 16-micron Aerosonic held 10 kg per square inch on 66 g of film a pallet, against 9.9 kg per square inch on 200 g for 23-micron solid film. Cost varies with film price and pallet size.
The pallet that gets opened for inspection and rewrapped by hand
An inspection means somebody cuts your wrap off. What happens next decides whether the load finishes the journey in the condition it started in. It is usually rewrapped by hand, on a cold dock, by whoever is free — and a hand rewrap is where film consumption, wrap time and containment quality all fall apart at once.
Toreto measured that job. In a field test in the United Kingdom in August 2026, a difficult pallet that had arrived machine-wrapped with several film failures had its film cut off and weighed, then was rewrapped by hand from the Hyper Wrap System dispenser and weighed again. Conventional hand stretch film: 181 g, two minutes, £1.00 a pallet. Hyper Wrap System: 151 g, one minute, £0.74. Labour is the same operative at £0.20 a minute.
Be precise about where that saving sits: 50% fewer metres went onto the load, because the film is stronger and wider, while the weight fell only from 181 g to 151 g. The film and its dispenser frame are sold only together; the frame with a full roll on it weighs about three kilograms, and the operator walks half the way round the pallet. Andy Chinnery, after the test: “I am 64 years old and have a bad back, yet I still achieved an excellent result with ease.”
What has to stay readable, and what your certificate actually covers
A wrapped pallet still has to be read. Case markings, lot codes, country of origin, the labels your importer's system scans on arrival. If the wrap — or the condensation under it — makes any of that unreadable, you have a problem that has nothing to do with the goods. Confirm with your importer what must stay visible on the outside of the finished pallet.
Be equally precise about certificates, because this is where claims quietly drift. A chain-of-custody certificate is not a food-contact declaration. Toreto holds FSC Chain of Custody, FSC-C227420, which covers responsible fibre sourcing and nothing else. If your customer needs a food-contact statement for a material that touches the product, ask for that document by name, from whoever issues it.
The questions to take to your importer before you change the packaging
Which authority sets the plant health requirement for this product and this destination, and what does the current version of it say? Is a treatment or temperature regime required in transit, and does it constrain the packaging? Does the pallet have to be presentable for inspection, or unwrapped for it? What markings must stay visible? Who rewraps a load that has been opened, and with what?
Get those answers in writing from your importer or your inspector — not from a supplier catalogue, and not from an article. Then specify packaging to fit them: a wrap that lets the load breathe and stay dry across the route, cases that let air move through the stack, and a hand-wrapping method that can restore the pallet once it has been opened.
Frequently asked
- Does perforated pallet wrap keep fruit flies out of a load?
- No, and it should not be sold that way. The perforations are engineered apertures rather than tears, but no stretch wrap — solid or perforated — is an insect barrier. Quarantine pests are controlled in the field, in the packhouse, in the primary packaging and by the treatments your destination requires. Ask your inspector or importer what applies to your product and route.
- Can packaging alone prevent a customs rejection?
- No. Plant health status and documentation are decided by the destination's authority and by your paperwork, and packaging plays no part in either. What packaging decides is condition — whether the pallet arrives dry, upright and readable, or wet, leaning and mouldy. That is the failure you can engineer out, and it is worth doing on its own merits.
- Our loads are pre-cooled, so why do they still arrive wet?
- Because pre-cooling rarely reaches the core of a pallet, and produce keeps respiring afterwards. Under a solid film that heat and vapour cannot leave, so humidity climbs and water forms on the inner face of the wrap at every temperature change on the route. A breathable film such as Aerosonic lets both out instead of trapping them against the load.
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