For Cabot Creamery Cooperative, fresh is best. That's why the company is using the new KwikCool Induction Unit developed by Delkor Systems, Inc. to shave off as much as 30 percent of the time required for its cultured dairy products to cool between packaging and shipping.
"If we can save a day in the cooling process, that means our product is one day fresher for our customers," says Marcel Gravel, plant manager for Cabot Creamery, a dairy cooperative based in Cabot, VT. "Cooling the cultured product quickly creates better quality and longer shelf life."
Using Delkor's patent-pending invention, Cabot has also been able to reduce the work-in-process at its facility and increase throughput. At the same time, Gravel says, the dairy manufacturer has seen proportionate energy savings for each case of cultured product in the 80,000 square-foot refrigerated facility in which the product is cooled to the proper shipping temperature.
Cabot is best known for its cheddar cheese, which is distributed nationally. However, the co-op manufactures and distributes a number of other dairy products, including butter, cottage cheese, sour cream, Greek yogurt and flavored dips. These products are distributed regionally, primarily in New England and along the Eastern Seaboard.
Thermal processing followed by rapid cooling
During the processing stage of production, the temperature of cultured dairy products can be raised to 50° to 90°C, Gravel says. This is done to facilitate homogeneity, reduce viscosity or to destroy pathogens. Perishable goods such as cultured dairy products can be spoiled by transient periods at even moderate temperatures, so rapid cooling of the final package is of critical importance.
Gravel says the packages must be cooled to at least 45° F or cooler before they can be shipped. This can take up to 72 hours, depending on the container size, type of secondary packaging, pallet patterns and refrigeration temperature. On larger containers, he adds, cooling time has been cut by as much as a full day. Cabot uses a puck-shaped recorder that is placed inside pallets to determine when the product has reached the shipping temperature.
The cultured products are filled into a variety of plastic containers ranging from 6 to 32 ounce, says Terry Johnson, cultured packaging supervisor at Cabot. The containers are then conveyed to a Delkor Spot-Pak loader, where they are placed on flat, corrugated pads and held in place by a temporary bond adhesive while they are shrink-bundled for shipment.
The film conforms tightly and completely around the packages when they pass through a heated shrink tunnel, creating a barrier that protects the products inside as well as a unitized bundle for handling and transport, says Kevin Weiss, Delkor product line manager. However, he adds, the film barrier also acts as an insulator, restricting airflow and limiting thermal dissipation.
Punches C-shaped apertures in the film
Cabot has found that cooling time can be dramatically reduced through the use of the Delkor KwikCool Induction Unit. Weiss says the KwikCool vents the film in strategic locations to allow much better airflow between wrapped containers, especially when cases are stacked on a pallet. The KwikCool Induction Unit is installed on the wrapper and punches C-shaped apertures in the film just before it is wrapped around the containers. The apertures are placed in the areas between the tapered containers commonly used for cultured dairy products. By locating the perforations where film tension is low, packaging integrity is preserved while airflow is greatly increased, Weiss says.
Randy Swartz, maintenance manager at Cabot, says several years ago the dairy company began experimenting with ways to reduce the cooling time. They installed six turbo fans that blew 32° to 33° air at the wrapped containers as they were conveyed 80 feet from packaging to pallet stack-down.
He said they tried various shippers, and found that corrugated containers took much longer to cool the product. After Cabot changed to shrink wrap, they tried drilling holes in film rolls and even designed their own system that punched out circles of film. Much of this early work was done by Dean Lafoe, a machinist at Cabot, who designed the first punch system the co-op used.
"The problem is that the holes never hit in the right space to get the heat dissipation we needed," Swartz says. He adds that they also found that the fully punched chads of film clogged the shrink tunnel as the film melted onto the equipment.
Can be retrofit to most shrink-wrap machines
At that point, Cabot turned to Delkor, the maker of their secondary packaging equipment. Working as partners and building on Cabot's experience, Delkor engineers configured a system to consistently place the perforations where they are needed. The unit can be installed on any conventional shrink-wrap machine.
Using an array of cylindrical cutters, Weiss says, the device punches the film while it is stationary, waiting for the next package to enter the machine.
"Cabot has been running these perforators every day for some time," says Swartz. "They run very well and require little maintenance."
The KwikCool device is in use at other major dairy facilities in different parts of the U.S. Those companies also report dramatic reductions in cooling times, with the associated boosts in productivity and energy savings.
Cabot plant manager Gravel points out that any company planning to add refrigerated space might be able to reduce the required space by using Delkor's KwikCool Induction Unit: "We were looking for something more economical that would work within our tight footprint. KwikCool has given us savings in so many areas."
