Episode 7: It Was Never the Film

Episode summary

In 2025 the Porter County Cheesemakers Guild surveyed its nine member creameries and found that 3 to 9 percent of retail packs were coming back: mold under the film, “leakers” that lost vacuum in the case, and puffy packs in summer. The guild assumed it needed a better barrier film and asked Dr. Grace Nakamura which one to buy. She proposed testing the assumption first.

Hallie Brekken, the student lead, describes the three parts of the project run out of the Center for Packaging Innovation: return autopsies on failed packs the creameries save in dated freezer bags; shelf-life trials of four films stored at 38 °F, in the dark and under retail case lighting; and line visits, where students spend a packing day at each creamery with a stopwatch and a checklist and are not allowed to suggest anything until they have written down what is actually happening at the seal bar.

After thirteen months and nearly 400 returned packs, the answer is mostly not the film. About six in ten failures were seal-channel leaks — tiny wrinkles across the seal line, almost all on hand-loaded chamber machines — and only about one in eight traced to the film itself, though the cheapest film did badly under case lighting. A student-designed loading guide, a cut acrylic plate that centers the wedge and tensions the bag, costs about $40 to make in the Forge Prototyping Lab. At the first two creameries to use it, leakers fell from 6.8 percent of packs to 1.9 percent. It goes to all nine creameries this fall, with a short training video.

Chapters

Selected transcript

An excerpt, lightly edited for reading. The full speaker-labeled transcript is in your podcast app’s transcript view, or email podcast@uwporterfalls.edu for an accessible document.

Abe Tollefsrud: Hallie, what is a return autopsy?

Hallie Brekken: Exactly what it sounds like, minus the dignity. Every creamery keeps a freezer bag of packs that came back from stores, with the date and the store written on it. Once a month we drive around and collect the bags. Then we open each pack, dye-test the seal, measure the oxygen left in it, and photograph whatever went wrong.

Corinne Lacasse: And what went wrong?

Hallie Brekken: Mostly wrinkles. If the wedge goes into the bag a little crooked, or the bag isn’t smoothed, you get a tiny fold right across the seal line. It looks sealed. It isn’t. Air finds that channel in about a week.

Grace Nakamura: Everyone wanted the answer to be a better film, because you can buy a better film. I understood that. I came from industry, where you can always buy something. But the data kept pointing at the seal bar.

Abe Tollefsrud: How did the cheesemakers take that?

Grace Nakamura: Better than you’d think, because of how the students behaved. My rule is that on a line visit you watch and you write it down, and you don’t offer advice. A creamery packing three hundred wedges on a Friday afternoon does not need advice from a sophomore. It needs an accurate description of what’s happening.

Hallie Brekken: The advice came later, in a one-page summary, and only to that creamery. Nobody else in the guild sees your numbers unless you say yes.

Corinne Lacasse: And the fix is a piece of plastic.

Hallie Brekken: Acrylic. Forty dollars and a morning of practice. I’m a little offended at how well it works.

Links mentioned

• Keeping farmstead cheese sealed (research spotlight)
• Dr. Grace Nakamura
• Center for Packaging Innovation
• Fermentation & Food Innovation Laboratory
• Forge Prototyping Lab
• PKG 3500 Food and Pharmaceutical Packaging
• Packaging Technology program
• Nine seconds to the first bandage: a packaging alum’s medical kits (magazine)