The Northern Rivers is one of the most productive agricultural regions in NSW, macadamias, bananas, sugarcane, blueberries, avocados, coffee, and a wide spread of mixed horticulture across the Richmond, Tweed and Clarence valleys. Every one of these operations depends on packing sheds, produce storage buildings, and cool rooms that hold harvested product, sometimes for hours, sometimes for weeks, before it moves on to market. In a subtropical climate with high humidity and heavy seasonal rainfall, these buildings face a mould risk that’s distinct from a typical residential or retail problem, and one that carries direct consequences for produce quality, food safety compliance, and in some cases export certification.
This guide covers where mould develops in Northern Rivers farm buildings and packing sheds, why it matters beyond the building fabric itself, and what an appropriate remediation and prevention approach looks like.
Why Packing Sheds and Farm Buildings Are High-Risk for Mould
Packing sheds and produce storage buildings combine several conditions that push mould risk higher than an ordinary commercial building. Large open structures with high roof lines and limited insulation experience significant temperature swings between day and night, generating condensation on the underside of metal roofing and on structural steel, particularly through the cooler months when the temperature differential is greatest. Produce itself, especially freshly harvested fruit and vegetables, releases moisture as it respires, and in a packing shed handling volume through the day, that moisture load adds up inside a building that often wasn’t designed with active dehumidification in mind.
Northern Rivers’ rainfall and humidity compound this. Sheds built decades ago, when many of the region’s macadamia and banana operations were established, were generally built for weather protection and workflow rather than moisture management. Roller doors left open for airflow and vehicle access during the working day let humid outdoor air in freely during the wet season, when outdoor relative humidity regularly exceeds 80%. Timber packing benches, cardboard and timber pallet storage, and any porous packaging material stored on site all provide an organic substrate that mould can establish on once ambient moisture is high enough.
Cool rooms and refrigerated storage add a further risk pathway. Even at typical cool-room temperatures of 4 to 8°C, several mould species remain capable of slow growth, and condensation on cool room walls, ceilings, and around door seals is common where refrigeration units aren’t properly maintained or where door seals have degraded. Produce stored in a cool room with active mould growth on adjacent surfaces is at risk of cross-contamination even without direct contact.
Where Mould Establishes in Packing Sheds and Farm Buildings
Roof and structural steel condensation. Metal roofing without sarking or insulation is prone to condensation dripping onto packing benches, stored produce, and cardboard packaging below. Mould on the underside of roofing and on exposed purlins is a common finding in older sheds.
Packing benches and timber structures. Timber benches and structural framing that stay damp from produce handling, cleaning water, or roof condensation develop surface mould, and in more advanced cases, structural degradation of the timber itself.
Cardboard and packaging storage. Stored cartons, pallets, and packaging materials in a humid shed environment are one of the most receptive substrates for mould in the entire operation, and mould here presents a direct produce contamination risk if affected packaging comes into contact with product.
Cool rooms and refrigerated storage. Condensation on walls, ceilings, and evaporator units, particularly where door seals have degraded or where the refrigeration system isn’t maintaining consistent humidity control, is a common and persistent problem.
Amenities and staff areas attached to sheds. Toilet blocks, lunch rooms, and change facilities attached to packing sheds face the same ventilation and moisture challenges as any commercial amenity space, often with less maintenance attention than the produce-handling areas themselves.
Food Safety and Compliance Considerations
Produce packing and storage operations that supply retail, wholesale or export markets operate under food safety frameworks that treat mould in the handling and storage environment as a direct compliance issue, not simply a maintenance nuisance. Under the Food Standards Code and the NSW Food Act 2003, premises used for the handling, packing and storage of food, which extends to fresh produce packing sheds supplying commercial markets, must be maintained in a condition that prevents contamination. Visible mould in areas where produce is handled, packed or stored, or in a position where spores or condensation could contaminate product, is the kind of finding that draws attention from council Environmental Health Officers and, for operations supplying larger retailers or export markets, from third-party food safety auditors assessing compliance against schemes such as Freshcare or HACCP-based systems.
Beyond the regulatory angle, mould in a packing environment is a direct commercial risk. Produce quality claims from buyers, rejected loads, and damage to a grower’s reputation with a wholesaler or retailer over recurring quality issues can be more costly than the remediation itself. For operations that have had any compliance finding or buyer complaint related to condition of the packing environment, addressing the underlying mould and moisture issue, not just the specific complaint, is the more durable response.
Appropriate Remediation for Farm Buildings and Packing Sheds
Farm building and packing shed remediation differs from a typical residential or retail job in scale and in the practical constraints of an active agricultural operation:
- Assessment during a realistic operational window. Packing sheds often run on a seasonal harvest cycle, and remediation is best scheduled around the lower-activity part of that cycle where possible, rather than during peak harvest.
- Professional mould remediation appropriate to the affected material, structural steel and roofing generally responds to surface treatment, while degraded timber benching or framing may require replacement rather than treatment in place.
- Food-contact-appropriate products for any surface that comes into direct or indirect contact with produce, with product safety documentation available for your records and for any buyer or auditor review.
- Cool room and refrigeration assessment, including door seal condition and evaporator drainage, alongside the mould treatment itself, addressing the mould without fixing the underlying condensation source simply resets the clock.
- Written documentation of the assessment and remediation, useful both for your own records and to demonstrate a proactive response if a compliance or buyer query arises.
Prevention for Northern Rivers Packing Sheds
Prevention in this setting comes down to controlling moisture at the sources specific to a packing and produce storage environment: improving roof insulation or adding sarking to reduce condensation drip, managing roller door and ventilation timing to limit humid air ingress during the wettest parts of the year without compromising workflow, keeping cardboard and packaging storage off damp floor areas and away from roof condensation zones, and maintaining cool room seals and refrigeration performance on a proper service schedule rather than reactively. A periodic professional inspection, timed for the shoulder period before peak harvest, identifies developing problems while they’re still straightforward to address rather than during the operational pressure of the season itself.
Frequently Asked Questions
Can mould in our packing shed actually affect the produce itself, or is it just a building issue?
It can be more than a building issue. Mould spores can settle on produce or packaging directly, and mould growing on cardboard or timber that comes into contact with product creates a genuine contamination pathway. Where mould is present in active handling, packing or storage areas, it should be treated as a produce quality and food safety issue, not only a maintenance one.
Do we need food-safe products for mould treatment in a packing shed?
For any surface in direct or indirect contact with produce or packaging, yes. Your remediation contractor should be able to confirm the products used are appropriate for use in a food handling and storage environment and provide the relevant safety data sheets for your records.
How often should a packing shed or cool room be inspected for mould?
An annual inspection is a reasonable minimum, ideally scheduled in the shoulder period before peak harvest so any findings can be addressed before the operation is under seasonal pressure. Cool rooms and refrigerated storage areas warrant closer routine attention given how persistent condensation-driven mould can be there.
Our cool room has visible mould around the door seals. Is this urgent?
It’s worth acting on promptly. Degraded door seals both cause the condensation that supports mould growth and allow warmer, more humid air to enter the cool room, undermining refrigeration performance as well as creating a produce contamination risk. Addressing the seal and the existing mould together is the appropriate response rather than treating the mould alone.
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