Thermoformed Skin Packs Catch Attention, Hook Consumers

To accommodate retailers’ and consumers’ growing demand for case-ready skin packs of fresh fish, this seafood processor and packager turned to flexible, high-speed thermoforming equipment that makes sanitation easy.

North Coast Seafoods operates out of three USDC Grade A compliant processing facilities in Chatham, New Bedford, and in the Boston Seaport District, where Packaging World visited. Each facility undergoes voluntary inspections by the US Department of Commerce and the FDA.

The company sells its North Coast Chef’s Catch brand fish, both fresh and frozen, through club store retailers like BJ’s and Costco. North Coast recently began adding value to the previously unadulterated fish fillets in the form of slices of herbed butter, added seasoning, or other in-pack value-adds that are aimed at simplifying meals and demystifying seafood recipes for consumers. 

But delivering fish to retail is a challenge, especially fresh fish. Any faulty link in the chain from baited hook to retail cooler compromises the entire supply chain. Plus, waste or scrap is expensive and only gets more expensive as value is added in processing and packaging. 

In order to guarantee the freshest fish imaginable, North Coast vertically integrated its business from dock to door to control every part of the process. Such under-one-roof ownership produces an unbroken chain of custody spanning the time on water, to how the fish are caught, to who catches them, to fish handling, to the way they’re processed, to—most important for our purposes—how the fish are packaged and routed to retail. Vertical integration makes the process trackable and verifiable every minute the seafood is in North Coast’s possession. This way of doing business also lets the company set its own pace in throughput, buying it more hours or even days of unfrozen retail freshness. 

“Fish is unique in its timing and pace, and how fast the product moves,” says Jim O’Hara, Director of Operations at North Coast Seafoods. “We don’t keep any inventory. Everything comes in and goes out immediately. It’s a constant, fast-moving flow. And we have to carefully connect production with logistics and timing, so there are a lot of moving parts, and they’re moving fast.”

Automating fish packaging with thermoformed skin packs
That sort of speed lends itself to automation. There’s less opportunity for it in fish processing, which largely remains an artisan hand skill. But once the cod or haddock is broken down into consumer-sized fillets, packaging automation can keep up with the constant flow, at speed and at volume, without the heavy labor inputs that the processing side requires. 

“Finding labor is getting harder,” O’Hara says. “And labor’s expensive, that’s why we’ve got to automate things. All things considered, you’re going to spend $30,000 or $40,000 a year for a person. But if you can buy something automated, that costs $100,000, and it lasts more than a few years, there’s a quick payback. So I think you’re going to see that happening in a lot of industries in the next five, six years. It’s coming really quickly.”

The company recently has turned to vacuum skin-pack (VSP) thermoforming equipment to automate and provide shelf-standout packages for its fish. Of course, the primary function of a skin pack is to extend the fish’s shelf life. But compared to traditional vacuum packaging, the process adds characteristics that provide additional value, such as improved liquid retention. With VSP, as compared to say, MAP packaging, the upper and lower film in a skin pack are welded together on the entire potential contact surface, except of course for the space occupied by the product, thus safeguarding it, holding it in place, and retaining its appearance. 

Single and meal-for-two packs of fish are therefore center-of-the-bullseye applications for the skin-packing thermoformers at North Coast’s Boston processing and packaging facility. 

Case-ready sockeye programs inspire equipment upgrade
Last year, North Coast began a new sockeye salmon program for Costco and more recently another salmon program for BJ’s, featuring what the company calls its case-ready package format. 

Trays are thermoformed on the TFS 707 from roll stock via metal dies designed to accommodate the full range of fish sizes, shapes, and portions, including but not limited to 1x3, 2x3, or 3x2 formats. Fish and any value-add ingredients (pictured is Atlantic salmon with herbed butter) are currently hand-filled, but look for North Coast to apply robotic solutions for tray filling in the future.Trays are thermoformed on the TFS 707 from roll stock via metal dies designed to accommodate the full range of fish sizes, shapes, and portions, including but not limited to 1x3, 2x3, or 3x2 formats. Fish and any value-add ingredients (pictured is Atlantic salmon with herbed butter) are currently hand-filled, but look for North Coast to apply robotic solutions for tray filling in the future.

“This case-ready packaging format is great for a supermarket selling fresh fish right out of the case,” O’Hara says. “The skin pack seems to be getting more popular over the last few years. People like to grab and go. They don’t even have to go to the fish counter at their supermarket.” 

These two programs, vanguards of a larger trend leaning toward case-ready pack formats in fish, precipitated a technology jump at the Boston facility from legacy machinery to a faster, more robust thermoformer with in-line vacuum skin pack equipment. After shopping around, O’Hara decided on the TFS 707 in-line skin packing machine from Harpak-Ulma, a thermoforming machine specified for full sanitation. 

“Right after we got this machine—for the sockeye last year during peak season—we were doing 40,000 pounds a week,” O’Hara says. “And that’s 40,000 trays per week. We needed a big machine that could handle that volume and be flexible enough to do other varieties in other seasons. When we first got the TFS 707 up and running, we were doing 60 cases an hour, and we were right on the money all the time. But then we got even smarter. We knew how many cases we could get out of a roll [of tray material], so before long, we found out we could predict exactly when the roll was going to empty, too. So we could plan when we’d have to change rolls and time the runs accordingly. We got to be consistent, which was good.”

Machine particulars
Harpak-Ulma delivers the TFS 707 with its own proprietary Ulma PLC controls, or it can use Allen Bradley HMI and controls when requested. Components are standard components from Omron, and the machine controls are programmed and managed by Ulma, as is the case with the North Coast machine, unless otherwise requested. 

The semi-rigid trays that the machinery produces out of rollstock are constructed  of a laminated multilayer film with as many as 12 functional layers, including barrier, puncture-resistant, and shield layers, all bonded together by adhesive tie layers. The trays are formed on plates in variable depths, depending upon the size and shape of the fish, but the draw ranges from 30 to 50 mm. Tray forming is accomplished without plug assist; air pressure is sufficient. 

Changeovers to different packaging formats require plate changes, but O’Hara says re-plating is fast. A simple depth-of-tray change might take 15 minutes. Changing the tray length or width, say from 3 x 1 on a longer, full-length salmon fillet pack, to 3 x 2 arrangement for shorter cod fillets, for example, might take a half hour.

Once trays are formed, fresh fish is manually loaded into the trays, often alongside the aforementioned flavored butter slice or other flavoring value-adds. Two to three operators work the loading station to keep things running at the designated line speed. Loaded trays enter the downstream sealing station, where vacuum is used to heat and apply the lidding film. 

“The sealing station is basically a combination of vacuum and venting processes to arrive at the skin pack,” O’Hara adds. “There’s no mechanical seal made with the 707, it’s all done via vacuum thanks to unique lidding material.” 

Lidding material lets fish breath
Fresh fish still needs to breath, even after it has been processed. To prevent an anaerobic environment that would lead to spoilage or off flavors, North Coast Seafoods uses Cryovac Darfresh 10K OTR film from Sealed Air as the top film over a semi-rigid skin pack tray for all fresh fish applications on the TFS 707. This highly permeable film, designed specifically for vacuum-seal applications, complies with all FDA regulations. 


Darfresh 10K OTR has forming characteristics that allow it to totally surround the fish when vacuum sealed, preserving the fish’s color, flavor, shape, and integrity. It acts as a second skin, according to the company, with transparency that offers consumers the product visibility they desire to verify freshness themselves prior to purchasing. 

“That’s another reason we went with Harpak-Ulma, too,” O’Hara adds. “They have a partnership with Sealed Air around this Darfresh breathable film. The material was hard to work with at first, but the two companies figured out how to stretch it, tension it, seal it, and everything else. I was impressed because I was in their factory a few times when they were working on developing this film. I went down [to Harpak-Ulma’s nearby Taunton, MA, facility] and ran some samples and saw they figured everything out. It was seamless, it just worked great. And we haven’t had any issues since we’ve been using the system, either.”

Downstream from the thermoformer
Sealed skin packs are conveyed immediately downstream to an in-line pair of labelers and a checkweigher from Marel. The first labeler applies to the bottom of each tray a preprinted pressure-sensitive label containing cooking instructions, nutritional information, and other general information that isn’t specific to each individual pack. 

Each skin pack unit is then checkweighed, and information gleaned from the weight measurement is transferred to the next labeler, this one a thermal transfer printer, that prints a belly band specific to each pack and wraps the tray, adhering it with hot-melt glue. The preprinted multicolor bands use the North Coast Chef’s Catch branding, but leave an open window for the thermal transfer printer to specify the type of fish, barcode, unit price, weight, sell-by date, and other pertinent information unique to each pack. 

Currently, secondary packaging consists of hand-erected corrugated cases that are immediately hand-filled and hand-palletized at the end of the line, but O’Hara may be convinced to look into end-of-line equipment if the volumes and speeds continue to increase. 

TFS 500 thermoformer handles frozen fish
The TFS 707 for fresh fish is actually the second Harpak-Ulma installation at North Coast. Two years ago, O’Hara purchased a TFS 500 thermoformer that’s designed to vacuum pack frozen fish. Frozen fish doesn’t require the same breathable film as fresh fish, but the VSP packs still offer many of the advantages of the skin packs in terms of display and case-ready packing formats. 

The day of Packaging World’s visit, North Coast was running frozen, seasoned 6-oz salmon burgers on the TFS 500 in a three burger-wide by one burger-deep format with a perforation between each of the three trays. The top seal included North Coast-branded lidding film, and the three packs were being hand-loaded into corrugated cases in four counts for 12-pack corrugated cases of burgers. Polyvinyl chloride-based p-s labels from M&M Label were then hand-applied to the cases. 

“This TFS 500 is a workhorse of a machine, we’re working it eight to 10 hours per day,” O’Hara says. 

Aftermarket support
Aftermarket support has been somewhat of an afterthought so far on both the newer 707 and the existing 500 machines. O’Hara says he only needs to perform regular preventative maintenance on both for basic oil changes or getting out in front of wear part failure. 

“For the 500, which we’ve had for a little longer, we’ll have a technician come in maybe once a year and review the whole machine,” O’Hara says. “We might take a day to see if there are any wear parts we need to change, and we’ve gotten better at that, so we’ll have less downtime. But neither of the machines really causes any downtime. That’s critical today. When you have all the paid, skilled employees in the room ready to work, you don’t want to be down at all.”

Location is also an advantage since Harpak-Ulma is less than an hour away from North Coast. O’Hara has sent his techs to visit the OEM’s facility and spend the day every once in a while, just for continued training. 

“It’s a well-made machine,” O’Hara concludes of the TFS 707. “We researched different machines. We’ve used different machines, and we felt like this was the best-value machine and the best machine out there. Harpak-Ulma has proved to be a great partner and great as far as technical support.”

What’s next
The new TFS 707 at North Coast is currently hand loaded since the fish need to be delicately handled and benefit from the human touch. But new robotic end effectors using pneumatic grippers—O’Hara specifically mentioned those from Soft Robotics—make it possible to further automate the loading process with robotics, also from Ulma.  

“There are a lot of different companies that are taking advantage of different types of gripper tools, whether they’re doing steaks or fish or hotdogs,” adds Kurt Nelson, Harpak-Ulma. “Now there are a lot of different ways of doing it. Certain things don’t require a soft touch, in this case swordfish is pretty resilient. But if you’re looking at haddock, that’s more delicate. I think it’s really product dependent.”

“The interesting thing to me is that three of my existing vendors are all working with robots now,” O’Hara adds. “One of my packaging companies, one of my software companies, and clearly Harpak-Ulma is getting into it. So, it’s clear to me that robotics are coming.”  -PW

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