180 Years of of Freezing – and the AI revolution

How can AI help to make more delicious frozen fruits and vegetables? How can sensors save energy in the quick-freezing process? And how can you sell ice to the Eskimos? Answers in the article – and the upcoming episode of AGRI-FOOD.AI podcast!

Humans have always sought ways to preserve food. In hot areas, dehydration with sunlight and preservation with salt were the best methodologies, while in colder climates, freezing was the easiest way – first in winter. When frozen food naturally occurred, people discovered that the frigid air of winter could prevent food from spoiling. This natural freezing technique was utilized across regions, particularly by those living in arctic environments, such as the Inuit, who perfected these methods long before modern refrigeration technologies were developed.

The experiments with frozen food preservation began in the 19th century when innovators started to prolong winter under the 4-season climate with artificial freezing. One of the earliest pioneers was Thomas Sutcliffe Mort, founder of the world’s first freezing works in Darling Harbour, Sydney, Australia, in 1861.  Mort and his partner, the engineer Eugene Dominic Nicolle, developed a commercial ice-making patent that allowed the export of frozen goods. Though Mort did not achieve widespread success in international trade, his work paved the way for large-scale frozen food transportation.

With the advent of mechanical refrigeration systems, the true turning point arrived. First, in the 1880s, regular shipments of frozen meat began flowing from Australia and New Zealand to Europe. The first notable success was a shipment of frozen New Zealand sheep to London aboard the Dunedin in 1881. The international frozen food trade soon expanded, including shipments of chickens and geese from Russia to the United Kingdom. By 1899, companies like Baerselman Bros were regularly importing thousands of frozen birds to London using cold storage techniques developed by German engineer Carl von Linde. Linde discovered the refrigeration circle and invented the first industrial-scale air separation and gas liquefaction processes, which led to the first reliable and efficient compressed-ammonia refrigerator in 1876. He is the founder of Linde Inc. – still one of the largest producer of industrial gases.

The history of sales has a special hero in several case studies – without mentioning his name.  The hero was a Westinghouse salesman who sold refrigerators to Aleuts in Alaska. His irresistible offer was: to keep food fresh, cool AND soft. The benefit of ready-to-eat meat opened the markets for the thought-to-be unsellable product–   as before, due to the heavy minuses, Unganans had fresh but stone-hard frozen meat only.

The story went on in Labrador, Canada. Clarence Birdseye, an American inventor took part in a fur-trapping expedition in 1912. Meeting Inuits, Birdseye noticed that fish caught in Labrador froze almost instantly in the extreme cold, and when thawed, the fish retained its texture and flavor. This observation sparked Birdseye’s groundbreaking work on quick freezing, leading to a new era of frozen food technology.

In 1924, Birdseye developed two primary quick-freezing methods. The first involved packing food between two metal belts chilled by a calcium chloride solution. The second, more widely adopted method: he placed the food between hollow metal plates cooled by the evaporation of ammonia. This allowed food to be frozen quickly – so prevented the formation of large ice crystals that would otherwise damage the food’s texture. Birdseye’s methods revolutionized food preservation, making frozen food commercially viable on a large scale. He went on to obtain 168 patents related to his freezing techniques, packaging, and processes.

By the 1930s, Birdseye’s methods were adopted worldwide, and frozen food became more accessible to the public. For example, the Icelandic Fisheries Commission encouraged fishermen to use quick-freezing methods in 1934, leading to the formation of one of the first frozen fish companies in Iceland. The adoption of quick-freezing expanded further during World War II, as the U.S. military conducted experiments with frozen orange juice, ice cream, and vegetables, solidifying frozen food’s place in both commercial and military use.

Modern Technologies of Food Freezing

The core principle behind modern frozen food preservation is the same as Clarence Birdseye’s original discovery: freezing food quickly to maintain its texture and taste. However, technology has advanced significantly to meet the demands of global markets, improving both efficiency and cost-effectiveness.

Most frozen foods today are preserved using mechanical refrigeration, a process that utilizes vapor-compression technology like household freezers. However, for industrial-scale freezing, more advanced techniques are employed to enhance the freezing speed and product quality.

The basic method is air-blast freezing when food is placed in rooms with cold circulating air. This method is affordable and simple, but slow – making it ideal for large cuts of meat or fish but less effective for items requiring quick freezing. A variant of this method, known as tunnel freezing, involves placing food on trolleys that pass through a tunnel with continuously circulating cold air, allowing for faster processing.

For products that require faster freezing, belt freezers and contact freezing methods are often used. In belt freezing, food moves along a conveyor belt inside a cold room, while contact freezing involves placing food between metal plates or belts that have direct contact with refrigerants. This increases the efficiency of heat transfer, resulting in quicker freezing times.

One highly efficient variant of contact freezing is plate freezing, where food is placed between metal plates that press against the product. This method is particularly effective for freezing flat items like fish fillets or packaged meals. A more specialized form is contact belt freezing, which combines conveyor belts with plate freezing to freeze items like fruit pulp, egg yolks, and soups.

For smaller food items such as peas or berries, fluidized bed freezing is a common technique. In this process, food is blown by fast-moving cold air, causing the food to “float” in the air, allowing for even and quick freezing. This method is part of a broader category known as Individual Quick Freezing (IQF), which ensures that each item freezes separately rather than clumping together in a block.

Another method still in use today is immersion freezing, which involves dipping the food into a liquid refrigerant like liquid nitrogen or carbon dioxide. This process rapidly freezes the outer layer of the food, locking in moisture and flavor. Liquid nitrogen, which operates at extremely low temperatures (as low as -196°C), allows for the fastest freezing times, but its high cost limits its use to premium products like seafood, fruits, and berries.

As technology has evolved, the frozen food industry has continually sought ways to improve freezing speed and maintain food quality. Cryogenic freezing, using gases like nitrogen, has been refined to achieve better results in terms of texture and flavor preservation, while mechanical freezing methods continue to advance in terms of energy efficiency and cost reduction.

Sensors and AI – present and future

Traditionally, quick freezing focused on rapid temperature reduction to preserve nutrients and texture, but advancements in digital technology have introduced new dimensions to the process. Digital sensors, AI, and continuous monitoring systems have transformed quick-freezing by enhancing efficiency, precision, and quality control.

Digital sensors monitor key variables such as temperature, humidity, and air velocity in real-time, ensuring that optimal conditions are maintained throughout the freezing process. These sensors allow for more accurate regulation of freezing parameters, minimizing the formation of large ice crystals, which can damage vegetable cell structure. This precise control helps produce higher-quality frozen vegetables, preserving freshness, taste, and nutritional value.

AI plays a central role in analyzing and responding to the data collected by the sensors. Through machine learning, AI algorithms can predict optimal freezing cycles for different types of vegetables, adjusting the process to account for varying moisture levels, density, and size. For example, AI systems can differentiate between leafy greens and dense root vegetables, fine-tuning the freezing process to suit each type’s specific characteristics. This level of automation reduces energy consumption, cuts down on waste, and increases throughput, benefiting both producers and consumers.

Continuous monitoring systems further support food safety and compliance by maintaining records of each freezing batch. This helps food manufacturers trace products back to specific points in the production chain, ensuring quality control and enabling rapid response to any issues. Together, these innovations in digital sensing, AI and monitoring not only improve the consistency and quality of quick-frozen vegetables but also support a more sustainable and cost-effective approach to food preservation in the industry.

And, with advanced sensor connectivity and AI integrated into a specialized model, we can create a digital twin of the freezing facility. Digital twins can model the entire process or, if needed, just a single phase. This “virtual factory”—your facility’s digital twin—enables you to experiment with small or large process adjustments to see what leads to the desired outcomes, all without making even a minor modification to your real, physical factory. Digital twins are incredibly useful, as we’ll explore in our podcast!

AGRI-FOOD.AI and Mirelit Mirsa are launching a pioneering project to enhance quick-freezing machinery! With 80 years of experience in the frozen food industry, Mirelit Mirsa operates a diverse range of machinery, some installed over a decade ago and others more recently. The key challenge is to integrate these conveyor belts, freezers, and packing lines using digital twin technology developed by the engineers at AGRI-FOOD.AI—all while keeping costs budget-friendly.

How can we optimize the freezing process to save energy and improve efficiency? What strategies can we implement to produce high-quality products without investing heavily in new machinery? Tune in to the AGRI-FOOD.AI podcast to learn more about this innovative approach!

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