Today, frozen foods are convenient and popular, and the statistics show it. The global frozen food market size was valued at $177.07 billion in 2021 and is expected to expand at a compound annual growth rate (CAGR) of 5.2% from 2022 to 2030, according to Grand View Research. According to an article published in Progressive Grocer in August 2021, the popularity of these foods including breakfast meals rose by 10.9%, and dinners/entrees were up by 4.9%. frozen meat, up 2.7%, and processed chicken (up 10.4%). Moreover, the utilization of these products by numerous end users such as full-service restaurants, hotels and resorts and quick-service restaurants will further support the growth of this market.
There is a plethora of frozen food products that have been individually quick frozen (IQF), and with good reason. From vegetables to delicate berries and fruit and from burgers to seafood, the IQF process seals in moisture while keeping product loss low. After the food is quick-frozen, today’s insulated metal-paneled, automatically zone controlled freezer/warehouse spaces keep food at the right temperature as it awaits distribution—all the while saving energy.
Refrigeration and freezing have a long history with slow and steady improvements, with IQF being one of the landmarks. In addition, modern construction techniques and automation have steadily increased improved cold storage capacity and capabilities.
Back in the 1960s, according to the McDonald’s website, a small family-owned beef business in the Philadelphia area set out to find a way to freeze beef patties in a method that would keep their taste and texture. Herb Lotman had a big idea: individually quick-freezing hamburger patties, locking in their juices and flavor. The rest is history. Lotman founded Keystone Foods, and teamed up with McDonald’s to develop a distribution system based on his quick-freezing technologies and a winning distribution concept. Today Lotman’s IQF process is in use worldwide with several food products—and Keystone Foods is one of the largest food companies with product distribution to more than 13 countries around the world.
IQF freezing and conventional methods
IQF freezers (for example, tunnel or spiral in structure) can use conventional ammonia or CO2-based mechanical refrigeration systems, but most often rely on cryogenic gases like liquid nitrogen or CO2. IQF foods you may have purchased include frozen shrimp, blueberries, vegetables, meatballs and hamburger patties—and sometimes the technique is used for prepared foods like pasta and pizza.
Impingement freezing is an IQF or rapid-freezing method, which directs high-speed airstreams from above and below the product. This method is typically applied to thin products (e.g., hamburgers, chicken fillets, shrimp, etc.) and achieves freezing in a few minutes. This method can be used with cryogenic or conventional refrigerants/mechanical systems.
Two other freezer types include plate and blast freezer—and while the former may use cryogens, the latter typically uses conventional refrigerants powered by mechanical compressor systems. Plate freezing is usually applied to brick-like products (e.g., packaged meals), and blast freezers are typically large spaces for bulk freezing where products typically remain for several hours or days.
COVID-19 pandemic and interruptions
The recent pandemic brought about several interruptions in the food distribution supply chain, and refrigeration systems were likewise affected. When food suppliers were shifting from food service/institutional to consumer/retail to meet the changing demand, processors needed to step up their cryogenic IQF capabilities. Many processors had been using CO2 in their cryogenic systems, but labor shortages and lack of CO2 availability forced cryogenic/freezer suppliers and processors to come up with alternatives.
“When our customers had to curtail production due to labor shortages and CO2 reliability, we quickly installed new chilling and freezing technologies to help boost throughput and to mitigate CO2 shortages,” says Mark DiMaggio, vice president of applications, marketing & execution at Messer Americas. “Our customers have accelerated their adoption of nitrogen and, given the ongoing CO2 supply challenges the industry faces during the pandemic, they are continuing to do so.”
In terms of large mechanical refrigeration systems found in industrial applications, ammonia, CO2 or a combination of both (cascade) are in use. According to Lauren Stephenson, Starfrost marketing manager, there has been a balance of both systems installed in the UK and Europe, however, there has been a recent increase in CO2-specific cooling equipment because it is perceived as having safety advantages over ammonia, and it is not a greenhouse gas as are some of the organic hydrocarbons.
Freezer types and refrigerant
Liquid nitrogen typically has been a preferred choice for impingement freezing when an instant crust freeze to lock in natural flavor and moisture is desired. However, as we said, conventional mechanical refrigerant systems can be used as well. For example, Octofrost released in 2021 an impingement system (the Multi-Level Impingement Freezer), designed for small footprints. Eliminating the need for liquid nitrogen reduces the operating costs for some food processors. The freezer uses three straight conveyor belts that can double production capacity per square meter of space. For frozen products requiring glazing, glazers can be installed at both ends.
Octofrost also builds a fluidized IQF freezer with bedplate technology. Depending on the application, processors often need to make a choice between IQF and static freezing, which means freezing in the cold-storage room, often taking some hours to freeze completely. Raspberries pose a special problem due to their fragility and moisture content. Most consumers prefer frozen raspberries to be IQF (so they remain whole)—not mushed together in a glob when frozen en masse. With IQF freezing, berries are frozen in minutes in a fluidized tunnel.
Why IQF for raspberries? Tests have shown that when IQF is used, dehydration ranges from 1% to 5%, while static freezing water loss ranges typically from 4% to 10%, which is many times more than the amount of weight loss. With IQF, Octofrost suggests that raspberry processors save up to 10% in yield and make more profits on the basis of dehydration alone.
IQF impingement freezers operating with liquid nitrogen can be used with sausage. Kayem Foods Inc. had installed a cryogenic tunnel freezer at its fresh sausage plant, but it couldn’t keep up as throughput increased. Two years later, Kayem installed a new Messer impingement freezer, which doubled the line’s freezing capacity in about the same space.
With the new freezer, the surface of the sausage is instantly crust frozen with a liquid nitrogen spray and high-velocity nitrogen gas, trapping moisture inside the product. As the sausage moves along the belt, it continues to be impinged from all sides with high-velocity nitrogen gas. This impingement freezing technology maximizes both production throughput and process efficiency.
After exiting the impingement freezer, the product is trayed, overwrapped, metal detected, labeled and put into a master case for final freezing—all in about 90 seconds.
Spiral freezers are capable of IQF and can use conventional ammonia refrigeration. Butternut Box, a dog food maker in the UK, uses freshly prepared, human-quality meat and vegetables for its products. Having moved recently into a 150,000-sq.-ft. facility, Butternut Box found it had space to invest in a spiral freezer to quick-freeze its products—rather than use a conventional static system.
Butternut Box selected Starfrost to provide an end-to-end freezing and cooling solution. Starfrost designed and built a double helix spiral freezer that operates on ammonia refrigeration. The freezer handles 4,000 kg. of vacuum-packed dog food pouches per hour, which has doubled Butternut Box’s production capacity. The double helix, automated freezer operates with two separate temperature zones, which significantly reduces the total number of kWs of low-temperature refrigeration needed to freeze the produce. This reduces both operational and energy costs of the system.
“Our new spiral freezer and refrigeration plant has assisted the business with doubling production this year,” says Marco Attanasio, head of strategic projects at Butternut Box. “The design specification also supports our overall growth plans allowing for future expansion. Since the installation of our new freezing equipment, we have considerably reduced our freezing times in comparison to the static freezers that were used before and the method of freezing is consistent which has greatly improved the quality of our end product.”
Cold storage construction: IMPs solve problems
Though insulated metal panels (IMPs) are hardly a new innovation, they have solved a couple of problems for A&E (architectural & engineering) firms in today’s post-pandemic world. The all-in-one modular wall assemblies can be put in place with just an installer—rather than multiple trades, which can lead to scheduling delays.
MWC, a joint venture among Glanbia Nutritionals, Dairy Farmers of America and Select Milk Processors recently moved into its nearly 400,000-sq.-ft. new facility in St. Johns, Michigan. MSKTD, the architect of record on the project, worked with A&E Shambaugh & Son and installer Eagle Enterprises of Michigan to install Kingspan KS Shadowline with QuadCore and KS Shadowline Interior with Quadcore IMPs. A total of 131,500 sq.-ft. exterior and interior IMPs met food processing guidelines and the construction timeline.
The IMPs have a standard finish of Imperial White siliconized modified polyester, which can withstand heavy sanitation used in processing plants. New technology allows for automatic equipment sanitization within the plant, along with daily cleaning shifts. The IMPs have an R value of 8 per inch.
IMPs go the distance (or height)
In another project, FreezPak Logistics opened its fifth state-of-the-art freezer warehouse facility—this one located on the border of two communities, Elizabeth and Newark, N.J.—about 20 miles south of the Newark International airport. In this case, FreezPak had one challenging requirement—to meet its height specifications, 72-ft.-long IMPs would be needed. In this case, Metl-Span was able to meet the specifications.
“FreezPak Logistics was looking to build a public refrigerated warehouse for frozen food storage,” says Kate Lyle, director, industrial cold and food at Ware Malcomb of Irvine, Calif. “A priority of the design was to maximize their building clear height, their ‘cube’ for the site. The overall building height was limited to 75 feet, and the design team worked diligently with Industrial Building Group and the developer to design a 66-ft. clear freezer.”
Part of the design goal was to minimize the number of stack joints for the IMPs around the freezer envelope. According to Lyle, Metl-Span was able to provide IMP lengths that, in spite of the building’s height, required no stack joints on two sides of the freezer. Cold Storage and Industrial Building Group of Montgomery, Texas, also worked with Metl-Span to develop details that covered the stack joint location with the blue accent stripe around the building and allowed for 32 faux windows to be attached to the outside of the metal panels. These faux windows were required by local jurisdictions.
“There were many jurisdictions in the U.S. that would not allow the building of a 75-ft.-tall freezer,” Lyle says. “The FreezPak Logistics project received the support of two jurisdictions: Elizabeth, N.J., where the project is located, and Newark, N.J., which is across the street from the site. The project brings much needed cold storage to support local businesses like grocery stores.”
“We went with Metl-Span because they could get us the 72-ft. panels we needed,” says Wade Hudson, project manager for Cold Storage Construction. “Also, having the panels delivered from their (Prince George) Virginia plant was the most economical.”
Cold Storage Construction installed more than 100,000 sq.-ft. of 6-in.-thick CF42 insulated metal panels with a 48 R-value; half of that square footage was made up of panels 72 ft. long. The exterior 24-gauge panels were coated with PVDF Almond. The remaining 20,000 square feet of interior partition metal panels were 4-in.-thick CF45 panels in SMP White. All interior panels were 26-gauge in SMP White.
One feature of the warehouse is that half of the building has an automated storage and retrieval system, and half is a standard vendor-neutral system.
“This is the seventeenth freezer building I’ve built, and we’ve used Metl-Span on all but one of them. And that one has some significant long-term performance issues,” says Karl Dickman, owner/partner of Industrial Building Group, LLC.
IMPs—Stainless steel or PVDF coatings?
While cold storage freezers and refrigerators in a warehouse environment don’t often receive washdowns like a wet process room, non-stainless-steel coatings may be used on interior-facing panels. However, I’ve been in my share of food facilities where washdowns occur regularly and often on a daily basis, and the interior surfaces of IMPs are almost always stainless steel (SS). I spoke with Arnold Corbin, technical services manager at Nucor Insulated Panel Group, a NUCOR company, and parent company of Metl-Span.
I asked Corbin, if there is anything new with IMPs. “There is nothing new, other than we are seeing value engineering away from stainless to painted surfaces due to material availability or to save money,” says Corbin.
“Painted surfaces in aggressive washdown or wet process areas will not last as long as stainless,” adds Corbin. In some cases, that can be as little as one year before the product fails. There are many variables that affect the coating performance, and it is impossible to predict how long a painted surface will last in these environments. One thing to note is: Just one repaint can be greater than the cost of using stainless steel during construction. In this case the cost of ownership is greater than the cost of construction. If you have to repaint every few years the cost of maintenance will far exceed the initial cost of stainless. A compromise would be to use a mix of painted and stainless with stainless just located in the wet process areas of a room, says Corbin.
“Also be careful of no-rinse sanitizing chemicals,” states Corbin. “Most food processing equipment is 316 stainless steel, which has good performance against sanitizing chemicals such as sodium hypochlorite. The common grade of stainless used for insulated panels is 304 which can be damaged by the long-term exposure to these chemicals. Always rinse after sanitizing when 304 is used or the sanitizing chemicals can cause corrosion.”
My next question: Use 304 or 316 SS, and what is the cost differential? Mike Petros, division sales manager – cold storage at TrueCore, a NUCCOR company, volunteers, “Unfortunately, the most scientific answer to this is, ‘it depends.’ The issue we face with 316 stainless is how we purchase it. Because it is not used often, it is not a standard sourced product in our industry. So, every time we need it on a project, we price it at the time of quote. That price is typically good for five business days, which is very difficult when you go through a standard construction cycle and bid process. We have seen the price of all stainless fluctuate drastically over the past 18 months or so, and while 304 has leveled off to a manageable spread, 316 is still very volatile. For this reason, many go into a project thinking that 316 is the direction they want to go, until they see the volatility around it.
“Spreads between 304 and 316 have ranged from 15% to 50% over the past year and a half,” adds Petros. “I wish I could give you something more concrete, but that is kind of the market that we are in today.”
Smart warehouse automation increases efficiency, saves energy
Opened in 2019 and operated by Dutch service provider NewCold, the XXL freezer in Burley, Idaho, has 90,000 storage positions and occupies 155,000 sq. ft., primarily serving McCain Foods. The 138-ft. tall automated warehouse has an AS/RS capable of operating in the dark with a throughput rate of 189 pallets per hour simultaneous storage and retrieval.
Constructed in cooperation with TGW, the facility features 14 levels of storage and is kept at a constant temperature of -13°F, while the temperature in the picking area lies between 23°F and 28°F. Storage and retrieval is based on a dark warehouse concept that allows additional energy reduction beyond the automaton that saves energy.
“Automation is one of the keys to meeting our customers’ needs. They are in the process of reorganizing their supply chains in order to achieve the greatest efficiency and the lowest costs possible,” explains Peter Verharen, vice president project management at NewCold. “Automation is the only way to achieve the throughput that the market demands.”
According to Verharen, automated freezer warehouses offer many other advantages as well: the space required can be reduced by up to 60% compared to manual warehouses—an important argument in areas where land is scarce and/or costly.
Modern technologies are the key to significant energy conservation. “With an automated rather than a manual freezer warehouse, you can not only double productivity but also save up to two thirds of the cooling energy,” notes Michael Schedlbauer, industry manager for grocery retail at TGW.
Today’s software solutions also offer the advantage of a transparent value-added chain. “That can be important in the case of product recalls, for example,” explains Schedlbauer. If worse comes to worst, manufacturers and logistics service providers need to be able to identify the affected products with just a few mouse clicks. Such supply chain transparency is only possible through digitalization and automation.