Capitalizing on winter frosts, consumers in cold climates have been freezing food naturally for countless centuries. The mechanical freezing of food dates to the 1860s, pioneered by Thomas Mort (1816–1878), who established the first commercial freezing works in Darling Harbor, Australia. In 1930, Brooklyn, N.Y., native Clarence Birdseye (1886–1956) patented his method to flash-freeze foods and deliver them to the public, an accomplishment considered to be one of the most important revolutions in the food industry.
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Fast forward to the present.
As of June 2019, U.S. retail frozen food sales totaled $55 billion for 52 consecutive weeks, according to Nielsen Retail Measurement Services (NRMS). Not surprisingly, ice cream was the most popular frozen food during that same time frame, per NRMS, with $6.7 billion in retail sales, followed by pizza ($4.8 billion), seafood ($4.8 billion), novelty ($4.6 billion), and complete meals ($4.5 billion). Following the top five are vegetables ($3.1 billion), cooked meat ($3.0 billion), fresh meat ($2.9 billion), appetizers ($2.1 billion), and potatoes ($1.8 billion). Categories rounding out the list are sandwiches ($1.7 billion), ice ($1.6 billion), breakfast sandwiches ($1.3 billion), main courses ($1.3 billion), fruit ($1.1 billion), and handheld entrées ($1.0 billion).
In 2019, in collaboration with the Food Marketing Institute, the American Frozen Food Institute (AFFI), based in Arlington, Va., released a research report, “The Power of Frozen in Retail,” that examined the consumption, purchase drivers, and use of frozen foods. These research findings, along with actual sales and consumption data, provide an overview of frozen food that equips frozen food manufacturers and their retail partners with opportunities for continued growth, according to Donna Garren, PhD, AFFI’s executive vice president of science and policy.
Founded in 1942, AFFI is a national trade association dedicated to advancing the interests of all segments of the frozen food and beverage industry. Highlights from the report address the retail frozen landscape in 2018, specifically:
- Frozen foods generated $57 billion annually in retail.
- A total of 99.4 percent of households purchase at least some frozen foods.
- The top three categories for growth in sales were pizza (+$232 million), novelties (+$211 million) and dinners/entrees (+$206 million).
- The top three categories with the largest percent dollar growth include appetizers/snacks (5.8 percent), soups/sides (9.8 percent, and breakfast foods (5.7 percent).
Addressing Food Safety Challenges in Frozen Food Industry
Dr. Garren observes that, currently, Listeria monocytogenes (Lm) and enteric viruses are pathogens that challenge global regulatory agencies and food manufacturers alike. “We’re addressing issues in this area by continuing to produce resources related to control and prevention of Lm, as well as exploring ways to support the frozen fruit industry in control and prevention of enteric viruses,” she relates.
To that end, in 2017, AFFI embarked on a strategic plan that prioritized the advancement of food safety within the frozen food industry supply chain, Dr. Garren says. “This was shortly after an Lm recall for frozen vegetables,” she notes. “We knew then that AFFI could be instrumental to our members and the collective frozen food industry in developing the science and best practices to ensure that frozen foods and beverages are safe.”
For this effort, Dr. Garren says, resources were developed with the support of more than 75 food safety experts representing the frozen food industry. All of this information is available for free on AFFI’s online resource, Food Safety Zone. “This website was launched in 2019 to provide frozen food and beverage manufacturers with best food safety practices aimed at Lm control and prevention in the areas of sanitation controls, hygienic design, environmental monitoring, process validation, hygienic zoning, and freezer management,” Dr. Garren relates.
Since 2017, AFFI has funded several research programs to build the body of scientific information around Lm and the public health impact of listeriosis. “Scientists at the University of Georgia [UGA], Cornell University, and the University of Minnesota are conducting these research projects,” Dr. Garren says.
For one example, a project at UGA evaluates current environmental monitoring practices being implemented across the frozen food industry to prevent and control Lm. “We’ve learned there is a need for facilities to review their sampling strategy, including the frequency and timing of sampling,” Dr. Garren relates. “A take-home message of the project is that facilities should focus on sampling for Lm at times and in places where they are most likely to find the pathogen, in order to get a more realistic assessment.”
All of the peer-reviewed publications resulting from the AFFI-funded research will be added to the Food Safety Zone, Dr. Garren notes. She shares that, since its launch, AFFI’s Food Safety Zone has resulted in some 30,480 page views, with more than 5,000 best practices resources downloaded.
Food Safety Partnerships
A recent AFFI collaboration with Mérieux NutriSciences has led to development of Lm Trend Tracker. “This program is designed to gather industry microbiological sampling data, which can be used to evaluate the implementation of our best food safety practices, develop new resources, and determine if AFFI’s recommendations should be modified or improved,” Dr. Garren explains.
A second partnership was developed with Intertek Alchemy to develop a Listeria-specific 12-month food safety training course that is tailor-made for frontline workers in frozen food manufacturing facilities and the broader food industry. “This program, called Listeria Stops Here, includes a variety of interactive content that keeps workers engaged for better retention, results, and risk reduction,” Dr. Garren elaborates, adding that AFFI ships a toolkit of training materials to participating companies.
The National Frozen & Refrigerated Foods Association (NFRA), a nonprofit trade association representing all segments of the frozen and refrigerated foods industry, is the sponsor of March Frozen Food Month, June Dairy Month, Summer Favorites Ice Cream & Novelties promotion, and the Cool Food for Kids educational outreach program. Headquartered in Harrisburg, Pa., the NFRA, founded in 1945, includes more than 400 member companies.
“Through our Easy Home Meals consumer-facing website and social media platforms, NFRA talks to thousands of consumers every day about frozen and refrigerated foods,” says Julie Henderson, the organization’s vice president of communications. “We share food safety tips on our Easy Home Meals website and blog, including storage temperature and time charts, and also tips on proper refrigerator and freezer cleaning to help ensure the quality and safety of the foods stored there.”
NFRA recently began collaborating with the Partnership for Food Safety Education (PFSE). “We’re looking forward to sharing resources and helping to get more food safety messages out to our large consumer audiences,” Henderson says. “Our goal is to begin implementing PFSE’s Safe Recipe Style Guide, which has all recipe directions begin with the basic food safety “measure of washing your hands with soap and water and includes instructions for keeping foods separated.”
To instruct students, NFRA has partnered with Young Minds Inspired, a provider of free educational outreach programs, to create downloadable activities for middle and high school consumer science and health teachers that address both food waste and food safety. “Curriculum materials relative to these topics have been emailed to more than 65,000 teachers throughout the U.S. since 2019,” Henderson relates.
Promoting Frozen Food Quality
Relative to food quality, NFRA is consistently telling the farm-to-table story of frozen foods, Henderson emphasizes: that it’s real food, just frozen. “We emphasize to consumers and educators that frozen foods are made from real ingredients picked at the peak of ripeness and flash frozen, sometimes right on the field, to lock in all the beneficial nutrients and keep them in their perfect, just-picked state,” Henderson elaborates.
With its “Real Food. Frozen” consumer public relations campaign, NFRA focuses on changing the current conversation and perceptions about what people can find in the frozen aisles. “The campaign promotes the real ingredients, culturally-inspired recipes, fresh flavors, and smart packaging that make our category of foods unique,” Henderson says.
In 2019, the campaign achieved more than 700 million impressions through influencer marketing, media outreach, strategic partnerships, and social media efforts on the NFRA’s Easy Home Meals consumer channels and EasyHomeMeals.com, Henderson mentions.
Freezing Technique in Development
A novel technique called isochoric freezing holds promise for use in food manufacturing and preservation, according to its developer, Boris Rubinsky, PhD, a professor of biomedical and mechanical engineering at the University of California, Berkeley.
Dr. Rubinsky first published the thermodynamic principles of isochoric cryopreservation in 2005 in the journal Cryobiology. His initial research focuses on using isochoric freezing for human cells and tissues, and organs destined for transplantation. Collaborating with USDA since 2017, Dr. Rubinsky and other scientists have shown that freezing various foods under certain isochoric conditions results in products with quality superior to those preserved by conventional freezing.
Typically, food is frozen under isobaric conditions, which means a constant atmospheric pressure when temperature and volume vary in tandem, Dr. Rubinsky relates. “Within such a system, an unrestricted volume of water or the total water content within a given solid mass of food will freeze almost completely when held at a temperature below its freezing point,” he explains.
With isochoric freezing, a food product is immersed in an isotonic solution inside a closed chamber so that the volume remains constant during freezing, Dr. Rubinsky elaborates. “The chamber is then gradually cooled down to a preset freezing temperature,” he says. “Once the temperature reaches the freezing point of the solution, ice starts forming and growing in size, generating hydrostatic pressure inside the closed chamber until the system reaches a new thermodynamic equilibrium at the preset freezing temperature. At this point, a two-phase system exists, with an unfrozen liquid portion and a frozen solid portion.”
The most notable benefit of isochoric freezing, Dr. Rubinsky says, is that food can be safely preserved without ice crystal formation if it remains in the liquid portion of the system. To date, the technique has been successfully demonstrated with studies on cherries, tomatoes, potatoes, and tilapia, Dr. Rubinsky reports. “Additional foods that could benefit from the process include berries and leafy greens, which deteriorate after traditional freezing and thawing,” he points out. “Moreover, isochoric freezing of bacteria in solutions at minus 15 degrees Fahrenheit for 24 hours has resulted in a seven-log reduction of Lm and Salmonella typhimurium.”
“Energy savings is another benefit of isochoric freezing,” Dr. Rubinsky adds. “Our research shows that an isochoric system requires up to 70 percent less energy compared to conventional freezing.”
Another game-changing breakthrough is on the horizon. “Our current research includes freezing for 3D printing of food—cryoprinting,” Dr. Rubinsky says. “That will have a major impact on the food industry worldwide. One day, in the foreseeable future, instead of first making a food product and then freezing it, we will be able to freeze a food product as it’s being made, courtesy of cryoprinting.”