History of cryogenic freezing of food

Cryogenic freezing as applied to food can be defined as very rapid freezing achieved by exposing food to a very cold refrigerant that usually undergoes a change of state while the food is being frozen.

The word ‘cryogenic’ comes from the Greek word ‘kryos’, which means cold and is simply study of materials at low temperature such as 77 K.

It is believed that the first ever successful liquefaction of any cryogenic gas was carried out not earlier than 1877, by a French mining engineer Cailletet who produced a mist of liquid oxygen droplets.

He succeeded in pre-cooling a container filled with oxygen at 300 atm and then expanding the gas by suddenly opening the valve of the container.

Scientist have been experimenting with the use of extreme cold to strengthen metals since mid 1800s, but it was not until the advent of space travel that cryogenic processing really came into own.

NASA engineers analyzed spacecraft that had returned from the cold vacuum of space and discovered that many of metal parts came back stronger than they were before spending time in space.

In the early 1880s, one of the first low-temperature physics laboratories the Cracow University Laboratory in Poland was established by Szygmunt von Wvroblewski and Olszewski.

They obtained liquid oxygen ‘boiling quietly in a test tube in sufficient quality to study properties in April 883. A few days later, they also liquefied nitrogen. Ten years later Olszewski and a British scientist Sir James Dewar liquefied hydrogen.

In 1902 Georges Claude improved the efficiency of air liquefaction by including reciprocating expansion engine.

From the early 1960s food freezing with liquid nitrogen developed very rapidly when it was found that food that is frozen cryogenically had superior quality to the frozen by mechanical freezing.

The method of cryogenic processing materials at sub-zero temperatures was first acknowledged when metal parts that were transported via train have been crammed with dry ice (at -79 ° C) resulting in perceptible increases in wear resistance.

Rapid freezing in liquid nitrogen prevents the formation of the large, long, needle-like crystals present in slow freezing, and less damage occurs to delicate food cells because the rupture of the cell walls during freezing is avoided.
History of cryogenic freezing of food

Development of Food Preservation

During the 20th century the continued application of scientific research to food production has significantly changed the way the world eats.

Food preservation is as old as human civilization. Preservation of foods inhibits spoilage cause by bacterial growth, oxidation, insects or desiccation.

The Chinese reportedly preserved vegetables by fermentation in prehistoric times and Plinius preserved white cabbage in earthenware pots in Italy in the first century AD.

The earliest recorded instances of food preservation date back to ancient Egypt and the drying of grains and subsequent storage in seal silos.

Fermentation, oil packing, pickling, salting, and smoking are all ancient preservation technologies.

Refrigeration in caves or under cool water were also well known ancient techniques of food preservation.

But the potential of this particular food preservation technique was not fully realized until the 1900’s when Clarence Birdseye introduced frozen foods to the American public.

People in many parts of the world developed techniques for drying and smoking foods as far as 6000 BC. Microorganism need water to carry out their metabolic processes.

Ancient Mesoamericans used salt as a preservative for trade in fish and other food stuff over long distances, as well as for storing food for long periods of time.

Since Phoenician times (from around 1250 BC) the standard practice for preserving fish was to gut it, dry it and pack it in layers with salt.

The first dehydrator for drying fruits and vegetables was introduced in France in 1795.

In 1803, a French chef named Nicholas Appert invented a new technique for preserving food.

He prepared and preserved soup, beef with gravy, beans and pea. The French navy store it for three months, Then they tried it. The food was delicious and safe to eat.

When Appert published this method in 1810 he had no knowledge of bacteria. It took another 50 years and Louis Pasteur to elucidate the relationship between microorganism and the spoilage of food.

In 1854 Louis Pasteur began his investigation in wine. And pasteurization process of milk was begun in Germany and United States in 1880 and 1890 respectively.

Freezing did not fully develop until the 1950s. Freezing keeps food safe by slowing the movement of molecules, causing microbes to enter a dormant stage.

It extended periods of time because it prevents the growth of microorganisms that cause both food spoilage and foodborne illness; so frozen food is theoretically safe forever.

The term of irradiation appeared only around 1950s, but the technology can be traced back to the late 19th century.

Although food preservation has now reached a high standard at least in the developed countries, the quantities of food still spoiled are astonishing.

According to estimates, no less than 20% of foods produced never reached the consumer’s table because of attack beforehand by rodents, insects or microorganisms.
Development of Food Preservation