Transporting heavy produce like onions, garlic, and citrus across the US via refrigerated trucks (reefers) involves a major hidden risk: Airflow Short-Cycling and Hot Spots.
Even if your reefer is set to a perfect 38°F (3.3°C), improper air circulation inside the trailer can cause localized temperature spikes up to 60°F (15°C), melting your profits through accelerated rot.
1. The Physics of Reefer Airflow
Reefer units blow cold air across the top of the cargo, which must then drop down, move through the floor channels, and pull back to the front.
- The Plastic Blockade: If you wrap your pallets tightly in standard plastic stretch film, or use solid cardboard bins, you create a solid wall. The cold air merely bounces off the top and sides, completely bypassing the hot, breathing produce in the center of the pallet.
2. Eradicating “Respiration Heat”
Onions and potatoes are alive; they generate heat via respiration. A single pallet of tightly packed onions can raise its internal temperature by 2°F to 3°F per day purely from self-generated metabolic heat.
- The Mesh Solution: Shipping in open-mesh produce bags ensures that the suction created by the reefer floor channels draws cold air directly through the core of the pallet. Metabolic heat is flushed out instantly, preventing “sweat” condensation.
3. Pallet Stacking for Max Airflow
- Never Block the Bulkhead: Leave at least 6 inches between the front wall and your first row of mesh bags.
- Use Honeycomb Stacking: When stacking mesh bags on pallets, alternate the direction of the rows layer by layer. This creates natural vertical chimneys for cold air to circulate freely.