What Is the Process of Pasteurization?
Pasteurization is the process of heating liquid food items to high temperatures and then cooling them suddenly to low temperatures before packing them into containers. The process is used worldwide for milk, both by the food industry and at home. This process kills the harmful microorganisms present in the milk, helps in increasing its shelf life, and makes it safe to drink, leading to its mass usage worldwide. Hence, the milk can be stored for a long time and used more efficiently, avoiding wastage. Another advantage of this method is that the taste and nutritional value of the liquid remain intact.
What Is Raw Milk?
Raw milk is the milk that directly comes from the farm animal and becomes available for consumption. There have been claims that raw milk is healthy, but these claims hold on scientific approval. Raw milk contains a lot of pathogens and is risky for health if consumed.
Who Invented the Process of Pasteurization?
Louis Pasteur, a French scientist, discovered the process of pasteurization in the year 1864. He had found this technique to extend the shelf life of alcoholic drinks used for social purposes, like wine and beer. Pasteurization proved beneficial for milk as well, and after that, it was widely accepted and used globally. It is the most familiar form of heat treatment used on milk today.
Why and How Was Pasteurization Discovered?
In the nineteenth century, the production of milk had risen exponentially, but it came with a demerit, that is, the increase in the death rate due to an upsurge in the diseases born from milk. Milk commonly contains bacteria like Mycobacterium tuberculosis, Salmonella, E. coli, Listeria, Campylobacter, and other non-spore-forming microbes that cause food poisoning. There was a prevalence of the diseases like tuberculosis, Q fever, diphtheria, severe streptococcal infections, typhoid fever, and other foodborne illnesses before discovering the pasteurization process. As the revolution gained momentum widely, the incidence of milk-borne disease outbreaks fell drastically. It came as a life-saving method, which led to less than one percent of reported attacks today.
The milk gets contaminated from a variety of sources, such as:
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Waste products of the animals, like feces and urine. All the three concerned parts are close to one another; contamination is relatively easy.
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Infections and illnesses of the animal udder.
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Skin flora of the animals.
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The surroundings and residing place of the animals that have dirt and dust.
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The animal food and the equipment and machines involved in taking their care.
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Drugs and medicines consumed by the animals for their treatment.
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Other neighboring animals on the farm carry disease-causing microbes.
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And the people dealing with the animals.
So to make the milk free from all contaminants, pasteurization is necessary before consuming it.
What Are the Different Types of Pasteurization Methods?
- Vat Pasteurization: This method is also known as Batch pasteurization. It was originally used by Louis Pasteur. The milk is heated to a temperature of 145℉ for 30 minutes.
- Continuous-flow Pasteurization: It is of the following types:
- High-Temperature Short time (HTST): In this method, the temperature of the milk is increased to 161℉ (71℃) for at least 15 seconds or 145°F (62°C) for 30 minutes with the help of metal plates and hot water, then the milk is suddenly cooled.
- Higher Heat Shorter Time (HHST): In this approach, the milk is heated within the range of 191°F (89°C) to 212°F (100°C) for 1 second to 0.01 second, depending on the selected temperature. The equipment used here is a bit non-identical to the HTST technique, and it is called a heat exchanger.
- Ultra-High Temperature (UHT): In this process, the milk is heated to 280°F (138°C) for at least two seconds in commercially sterile equipment. It is then filled under aseptic conditions into hermetically sealed packaging. The milk is cooled rapidly after that. This method kills good bacteria as well, besides harmful bacteria but gives a much longer shelf life to the milk. The milk treated by this technique does not need refrigeration until the pack is opened, and its shelf life prolongs for at least six months. The product obtained by this technique is known as shelf-stable.
- Ultra-Pasteurized (UP): This process is different from UHT. The milk is again pasteurized using commercially sterile equipment, but it is not considered clean because of its less stringent packaging. The temperature is escalated to 280°F (138°C) for at least two seconds, then cooled quickly. The milk served by this method needs refrigeration and remains fresh for 30 to 90 days.
Both UHT and UP-treated milk need refrigeration, and their expiring times after opening the package become the same as other products dealt with pasteurization.
The HSTS and UHT techniques involve the compelled flow of raw milk in the hollow pipes and thin plates of the metal. The temperature of the metal increases, which consequently raises the temperature of the milk. This technique keeps the milk heated for the appropriate time before it gets pushed into the cooling chamber of the pasteurizer. The milk is then suddenly cooled to a temperature below 41°F which further kills the pathogenic microbes that may have become inactive at high temperatures but may get activated at moderate temperatures. This milk is then packed in sealed containers and distributed for consumer use.
What Are the Myths and Facts About Milk and Its Pasteurization?
Like all other famous things, the process of pasteurization also comes with a list of myths and facts. They are as follows:
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Lactose intolerance and allergies are caused by both raw milk and pasteurized milk. The pasteurization process has no role in these reactions as they are caused by sensitivity to milk proteins.
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The pathogenic microbes are only killed by the process of pasteurization and do not destroy themselves.
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The nutritional content and value of the milk remain unaffected by pasteurization.
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All pasteurization processes do not ensure its safety without refrigeration once the package is opened.
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Pasteurization destroys the pathogenic microbes and prevents people from falling sick.
Conclusion:
The process of pasteurization provides many health benefits, particularly in relation to wellness, without showing any side effects. So, pasteurized milk should be used which is the key to healthy milk consumption.