Since its founding more than 20 years ago Ivanhoe NC-based Sweet Berry Farms has succeeded in providing the freshest blueberries by ensuring that the fruit is transported from the field into stores in just two days. Because time is of the essence the company can’t afford downtime on any of its six high-speed packaging lines.
“I can have the best crews picking the berries” says Chester Barnhill owner of Sweet Berry Farms “and the plumpest berries but if the containers don’t work on our lines we’re in for trouble.”
Originally Sweet Berry Farms was using a clear oriented polystyrene clamshell for its one-pint size. But every tenth container or so would crack when a pinch roller closed the lid over the blueberry container; the containers are conveyed single file down the length of the packaging line.
“Our previous containers had a horrible failure rate” admits Joey Benton plant manager at Sweet Berry Farms. “They would crack under the pressure of the pinch roller. That would jam the unit stopping sorting and filling operations. Many of the original containers got damaged on the truck and would be rejected by the supermarkets.”
To reduce container damage Sweet Berry Farms turned to Fabri-Kal (Kalamazoo MI) to develop a one-pint clamshell with a snap-fit lid. Although the blueberry grower packs different-sized containers the one-pint container is the only one supplied by Fabri-Kal with the K-Resin® material component. The container and lid are formulated of crystal polystyrene (XPS) blended with K-Resin styrene-butadiene copolymer (SBC) from Chevron Phillips Chemical Co. (Houston TX).
The materials provide not only strength and hinge flexibility but also clarity which is important for product merchandising. Most important the Fabri-Kal container runs consistently on Sweet Berry Farms’ automated production lines. No new equipment was needed to accommodate the new container.
The clear success
Other clear polymers including previously used OPS were considered stiff easy to crack and unable to provide the durability needed for a good hinge. K-Resin KR03 is used when extruding the material into sheet. The formulation also contains a microcrystalline wax that acts as an Antiblock a material that stops the containers from sticking together while they are nested.
According to package designers at Fabri-Kal K-Resin was also selected for its ease of processing. It can be extruded into a high-quality sheet with equipment normally used for high-density polyethylene or polystyrene. Manufacturing costs remain the same for all materials.
During packaging containers are conveyed from a denester underneath a hopper from which the blueberries gently descend into the container. The containers are then conveyed underneath the pinch rollers that shut and lock the lid to the container through locking tabs. Containers are conveyed to a labeler that applies a pressure-sensitive label to the top of the lid. Labeled containers are conveyed to hand-packing stations where workers pack them into corrugated flats for shipping.
In addition to requiring that the container run smoothly on its packaging equipment Sweet Berry Farms also required that the container stay closed provide proper cooling ventilation to maintain berry freshness and make the product visible to consumers.
“With the new container we could run our packing operation indefinitely” Benton says. “This one-pint container does it all and it stays closed. It’s a reliable container. Our customers rely on Sweet Berry for the freshest fruit. [The new container] helps us do just that by providing protective packaging that looks good on the shelf and works the way we need it to.” —ALR