From the types of seals and closures to the material used, tamper evident packaging can affect production line speed, end-product quality and consumer reaction.
Cold seal, for its advantages in line speed, comes with several disadvantages. By opening the package, a consumer reduces the adhesive properties. Mr. Kehrli said cold seal also doesn’t provide a complete oxygen barrier, therefore reducing shelf life.
When introducing heat into the packaging process, several complications can arise. Overexposure can cause polyethylene and polypropylene bags to melt. Mr. Lindsey said this messy occurrence happens when a line stops and the plastic bags are left in direct contact with the hot surfaces of sealing machines.
“Our sealer is a non-contact heat seal method, which literally means we do not have a heated belt directly in contact with the bag,” Mr. Lindsey said. “If product stops inside our machine, we divert heat away from the bag so it doesn’t melt it and cause problems for production.”
The TEC200 features user-friendly heat adjustment for temperatures ranging from 250° to 450° F. Two heat-resistant plastic belts run parallel to each other through the machine while the heat manifold blows hot air on the top and bottom of the bag as the belts guide it.
“As it comes through, we’re heating that bag up to the point where it fuses together, and then as it exits, it goes through a crimp roller so you can see that it is sealed,” Mr. Lindsey said. “The crimp roller gives the comfort that you can see a seal on there.”
Formost Fuji addressed the need for longer dwell time with heat seals by creating a swing rotary that provides for longer dwell time while not slowing down the rest of line. At interpack 2017, the company introduced its high-speed box-motion seal system that will run up to 400 packages a minute while still providing two to three times as much dwell time as previous models.
“We’re now able to use more sophisticated materials that require more dwell time for sealing and still run high speed,” Mr. Gunnell said.
Bettendorf Stanford offers baggers and a heat sealer that address the challenge reducing wasted material both in bagging as well as damaged products caused by overwrapping.
“Quite a bit of the scrapped product that is attributed to the wrap room comes from the overwrapper itself,” Mr. Atkins said. “If you can eliminate that, your costs and scrap rates go down, which means profit.”
The Betterndorf Stanford heat sealer can replace or work with a wrapper and features a resealable zip-lock style bag that is heat sealed after inserting the product. Mounted on the end of a bagging line, the heat sealing system trims the excess material off the bag.
“In general, consumers are flexible when it comes to the different types of packaging,” Mr. Atkins said. “What you should watch out for is when the product becomes difficult to open or requires the consumer to throw away excess packaging material.”
To create an effective tamper-evident seal, Mr. Gunnell recommended a test run with an equipment manufacturer. Formost Fuji’s test lab helps establish that bakers and snack producers use the right material at the maximum speed.
“It takes a partnership with the material supplier, the equipment supplier and the baker, and that is sometimes something that gets missed,” Mr. Gunnell pointed out. “If we don’t get the three legs of that stool all together in the same place at one time, it really causes a problem.”
