Powdered milk, alternatively termed dried milk or milk powder, undergoes a processing method where the liquid component is extracted, resulting in a finely textured powder. In the United States, it must not exceed 5% moisture by weight. This powder can be reconstituted with water to yield a liquid milk suitable for consumption. Valued for its prolonged shelf life, convenient storage, and adaptability in diverse culinary and food manufacturing uses, powdered milk holds significance in various applications.

HOW IS IT MADE?

The process commences with the collection of fresh milk from dairy farms, typically sourced from cows, though other mammalian sources may also be utilized. After collection, the liquid milk undergoes a dehydration process, primarily achieved through techniques such as spray drying or roller drying.

Spray drying

The first step in spray drying involves preparing the milk by homogenizing it to ensure a uniform mixture. The liquid milk is then pumped through a specialized nozzle, breaking it into tiny droplets. These droplets are introduced into a drying chamber, where they come into contact with hot air. The heat causes the moisture in the droplets to evaporate quickly, leaving behind dried particles of milk solids. The size of the resulting powder can be controlled by adjusting the spray nozzle and regulating the drying conditions. This allows manufacturers to produce a range of powdered milk products with varying textures and applications.

Preserving nutritional content stands out as a primary benefit of utilizing spray drying in the production of powdered milk. This method is specifically engineered to reduce heat exposure, safeguarding essential nutrients like proteins, vitamins, and minerals from degradation. This ensures the maintained nutritional value of the end product.

Roller drying

Roller drying, also known as drum drying, is an alternative method for producing powdered milk. It is also used for the manufacturing for other dehydrated flakes and powders. In this process, liquid milk is applied onto the surface of a heated drum or roller. As the drum rotates, the milk spreads thinly and is simultaneously exposed to hot air, leading to the evaporation of moisture and the formation of dried milk solids.

The roller drying technique imparts distinct attributes to the produced powdered milk. The steady rotation of the drum ensures a uniform and consistent heat exposure, facilitating a controlled drying process. The resulting milk powder exhibits a flaky or sheet-like texture, proving advantageous for recipes that require specific textures. However, when compared to spray drying, roller drying might involve slightly elevated temperatures, potentially resulting in the loss of some heat-sensitive nutrients.

One notable aspect of roller drying is its suitability for specific types of milk-based products. For instance, roller drying is often preferred for the production of instant or quick-dissolving milk powders. The resulting flakes or sheets can be easily broken down into a fine powder that quickly dissolves when reconstituted with water.

FORTIFICATION

The production of powdered milk, while offering practical advantages, carries the potential for unintended consequences. The widely utilized methods of spray and drum drying, while efficient in dehydrating liquid milk, can unfortunately compromise the stability of certain heat-sensitive nutrients. This is where fortification comes in.

Fortification in food refers to the intentional addition of essential nutrients, such as vitamins and minerals, to enhance the nutritional content of a product. This process aims to address nutritional deficiencies, meet specific dietary requirements, and provide consumers with a more comprehensive and healthful food option. In the case of powdered milk, common fortifications include vitamin D, calcium, and vitamin A.

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The fortification process is not arbitrary; it is intricately regulated to meet specific nutritional standards. Regulatory bodies establish guidelines to ensure that fortified powdered milk provides a consistent and reliable source of essential nutrients.

This precision in fortification not only compensates for potential nutrient losses during production but also aligns the powdered milk with established nutritional benchmarks. This reassures consumers of its reliability as a convenient and nutrient-rich alternative to fresh milk. In the US, the quantity of vitamin A and D, if included, must not be less than 2,000 and 400 International Units per quart, respectively.

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Powdered milk, alternatively referred to as dry milk or milk powder, is a dairy product obtained from liquid milk using a dehydration method. The liquid milk undergoes evaporation to eliminate a substantial portion of its water content. Subsequently, the concentrated liquid is converted into a dry, powdery state, often through techniques such as spray drying. The product is milk powder that serves as a convenient substitute for liquid milk, offering an extended shelf life and facilitating effortless storage and transport.

But, how enduring is this liquid milk alternative, really? Well, knowing powdered milk’ extended shelf life involves going beyond the surface of the “best-by” date.

HOW IS POWDERED MILK MADE

The production of milk powder involves a series of carefully controlled processes to transform liquid milk into a dry, shelf-stable form.

Initially, the primary ingredient—fresh liquid milk—undergoes a procedure referred to as evaporation. During this stage, the milk undergoes heating to eliminate a substantial portion of its water content. The objective is to condense the milk, increasing its density before advancing to the subsequent phase. This evaporation process, not only diminishes the volume for more convenient transportation, but also acts as the preliminary stage in eliminating moisture, a crucial element in preserving the integrity of the powder.

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/After evaporation, the concentrated milk is exposed to a process called spray drying. This is the pivotal step in converting liquid milk into a fine powder. The concentrated liquid is atomized into tiny droplets, which are then introduced into a hot air chamber. As the droplets travel through this chamber, the remaining water content evaporates, leaving behind small, dry particles of milk. The result is a powdery substance with a much longer shelf life compared to its liquid counterpart.

The last stage encompasses the packaging of the powdered milk in a manner that safeguards it against external factors, including moisture and light, ensuring sustained quality. Commonly, airtight containers or sealed pouches are employed to thwart moisture absorption and shield the powder from potential impurities. This packaging serves a pivotal role in maintaining both the flavor and nutritional content of the milk powder.

THE SHELF LIFE OF POWDERED MILK

Manufacturers put “best-by” dates on powdered milk. However, these are not hard and fast deadlines for spoilage. Instead, they indicate peak quality – the point where flavor and nutrient content might start to decline. The good news is, powdered milk boasts inherent resilience thanks to its dehydration process. This removes moisture, a key ingredient for bacterial growth, essentially putting the milk in a state of suspended animation.

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The duration powdered milk remains fit for consumption depends on factors like storage conditions, packaging, and the specific type of powdered milk. Typically, unopened powdered milk stored in a cool, dry environment can maintain its quality for up to two years or even more beyond the indicated “best by” date. Conversely, opened powdered milk has a comparatively shorter shelf life, and it is advisable to consume it within a few weeks to ensure optimal quality.

Nonfat dry milk (NFDM) boasts a lengthy shelf life when contrasted with whole dry milk. This is because of the extraction of fat content. The removal of fat acts as a deterrent to common factors like oxidation and rancidity. These chemical changes typically lead to the deterioration of food products. When stored unopened in a cool, dry location and within an airtight container, NFDM can endure for up to 25 years or even more. However, once the NFDM container is opened, its shelf life is diminished to approximately three months, according to Utah State University.

IS IT EXPIRED?

While powdered milk generally has a longer shelf life compared to liquid milk, various factors can contribute to its deterioration over time.

One of the most apparent signs of spoilage is a noticeable change in odor. Fresh and properly stored milk powder should have a mild, slightly sweet aroma. If the powder emits a sour, or rancid smell, it is likely an indication that the product has gone bad. The development of undesirable odors suggests the presence of spoilage microorganisms or the breakdown of fats within the powder.

Any deviation from the typical color, which is usually a creamy white, may indicate spoilage. Discoloration can manifest as yellowing or the presence of unusual dark spots. Such changes may be attributed to oxidation or the introduction of contaminants. A thorough visual inspection before use can help identify any potential issues with the milk powder.

Milk powder is intended to have a fine, powdery texture. The development of clumps or a change in texture, such as a gritty or lumpy consistency, suggests moisture infiltration. Clumping is a clear sign that the powder has absorbed water, leading to the formation of solidified clusters. Moisture not only compromises the quality of the milk powder, but also creates an environment conducive to the growth of microorganisms.

While milk powder may exhibit a slightly bland flavor due to the dehydration process, any noticeable off taste is an alarming signal of spoilage. An unpleasant or sour taste can result from the breakdown of fats and proteins within the powder. Performing a small taste test by mixing a small amount of powder with water can help discern any abnormal flavors.

The post How Long Does Powdered Milk Really Last? appeared first on The Food Untold.

Milk, a vital and widely consumed beverage, has undergone numerous technological advancements to extend its shelf life while preserving its nutritional value. One such innovation is Ultra High Temperature (UHT) treatment, a process that revolutionizes milk preservation. UHT milk undergoes a rigorous heating process that eliminates harmful microorganisms, ensuring a longer shelf life without the need for refrigeration.

The science behind UHT milk involves a delicate balance of temperature, time, and the understanding of microbial growth. This innovative technology has revolutionized the dairy industry, making it possible to transport and store milk for extended periods without compromising safety or taste.

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This post will explore the scientific aspects of UHT milk and how it differs from conventional pasteurization. We will discuss the key stages involved in UHT treatment, including the heating process and its effects on the nutritional composition of milk. Furthermore, we will examine the microbiological factors, including the elimination of harmful bacteria and the importance of aseptic packaging in preserving the milk’s sterility.

Let’s dive in.

WHAT IS ULTRA HIGH TEMPERATURE (UHT) MILK?

When you visit a supermarket, you may notice two different types of milk storage: refrigerated milk and milk displayed on a shelf at room temperature. The distinction between these two types lies in the treatment they have undergone. Refrigerated milk has typically undergone pasteurization, while the milk on the shelf has been treated with the ultra-high temperature (UHT) method.

Ultra-High Temperature (UHT) milk refers to a type of milk that has undergone an intense thermal treatment process to achieve an extended shelf life without the need for refrigeration. This preservation method involves subjecting the milk to extreme heat of 284°F (140°C) for 4 seconds. This rapid heating is crucial as it ensures the destruction of bacteria, yeast, and molds that may be present in the milk. By eliminating these microorganisms, UHT milk remains safe for consumption over an extended period, even without refrigeration. A properly packaged UHT milk should last 3 to 6 months or longer.

This is the reason why UHT milk can be safely displayed on the shelf at room temperature. Sure, pasteurized milk has also been heat-treated, but the temperature is relatively lower. The temperature for milk pasteurization is 162°F (72°C) for 15 seconds. This does not completely sterilize the milk. Hence, some microorganisms, although significantly reduced in number, may still be present. These remaining microorganisms can multiply and cause spoilage if the milk is not refrigerated.

The advantages of UHT milk are significant. It allows for the distribution and availability of milk in the regions where refrigeration may be limited or unreliable. UHT milk also provides convenience for consumers, as it can be stored at room temperature until opened. An opened UHT milk under refrigeration has a shelf life similar to that of fresh milk, 7 to 10 days.

HOW IT IS MADE

The process begins with the collection of fresh milk from dairy farms. Quality control measures are implemented to assess the milk’s composition, including fat content, protein content, and absence of any abnormalities or contaminants.

The collected milk undergoes pre-treatment to remove any impurities or particles. This involves processes such as clarification, centrifugation, or filtration to ensure a clean milk base for further processing.

The pre-treated milk is then subjected to ultra-high temperatures. In UHT treatment, the milk is heated rapidly at 284°F (140°C) for 4 seconds. This time and temperature combination varies, depending on the manufacturer and brand.

Following the heating process, the milk is rapidly cooled to bring it back to a safe temperature. This step is crucial to halt the heating process and prevent any further undesirable changes in the milk’s composition.

During UHT processing, the sugars in the milk, such as lactose, can undergo caramelization due to the intense heat. This process leads to the formation of new compounds and the development of characteristic flavors and colors associated with caramelization. However, caramelization can contribute to a burnt or slightly cooked flavor, altering the natural sweetness of the milk. The milk may also lose some of its original creaminess or richness, resulting in a slightly thinner consistency.

Once cooled, the UHT milk is filled into sterilized containers through a process known as aseptic packaging.

With aseptic packaging, the packaging materials undergo sterilization to eliminate any microorganisms on their surfaces.

The aseptic carton or Tetra Pak is the most prevalent type of packaging used for aseptic packaging of UHT milk. These cartons have several layers, including a layer of paperboard, an aluminum foil layer, and layers of plastic film. This mix of components creates a barrier against light, oxygen, and bacteria, assuring the milk’s long shelf life and safety.

UHT MILK NUTRITIONAL COMPOSITION

UHT milk retains many of the essential nutrients, including proteins and calcium, found in fresh milk. But here is the thing though.

Although protein is still present in UHT milk, the intense heat during the UHT process denatures the proteins in the milk. Denaturation refers to the structural changes in proteins due to heat exposure. This leads to a loss of their original shape and function. The high temperatures used in UHT treatment can cause denaturation of the milk proteins, altering their structure. Denatured proteins may have reduced bioavailability. So proteins in UHT milk may be less efficiently digested and absorbed by the body compared to those in raw milk.

Furthermore, the heat treatment involved in UHT processing can impact the solubility of specific minerals, such as calcium. While UHT milk provides a similar calcium content as other milk types, the high temperatures used in UHT treatment can cause calcium to become insoluble, leading to the formation of precipitates or clumps. For this reason, the body may encounter challenges in effectively absorbing and utilizing the calcium in UHT milk when compared to raw milk.

In a 2013 study conducted in Korea, the effect of various heat treatments on the solubility of calcium in commercial milk products was investigated. The findings revealed that raw milk exhibited the highest calcium levels, measuring 450.2 mg/kg and 444.2 mg/kg after two rounds of ultrafiltration. In comparison, UHT milk only contained 370.3-380.2 mg/kg and 371.3 mg/kg of calcium after undergoing ultrafiltration.

However, it is important to note that UHT milk still contains significant amounts of calcium. To compensate for potential calcium loss, some UHT milk products may be fortified with additional calcium to ensure an adequate intake of this essential mineral.

MICROBIAL DESTRUCTION AND STERILITY

The key principle behind UHT milk is the concept of thermal processing. This relies on the understanding that microorganisms and enzymes are heat-sensitive. Raw milk may contain pathogenic bacteria such as Listeria, Campylobacteria, Salmonella, Brucella, Cryptosporidium, and E. coli. When milk is exposed to such high temperatures, the heat disrupts the structure of these microorganisms. This renders them inactive and incapable of causing spoilage. Additionally, UHT treatment also inactivates enzymes that can lead to undesirable changes in flavor, texture, and nutritional quality.

After undergoing the Ultra High Temperature treatment, milk has to be packaged in a way that maintains its sterility and prevents recontamination. This is achieved through a process called aseptic packaging.

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Aseptic packaging involves filling the UHT milk into pre-sterilized containers under hygienic conditions. These containers are designed to create a barrier against any microorganisms or external contaminants that could compromise the milk’s safety and quality. Aseptic packaging is crucial in preserving the long shelf life of UHT milk without the need for refrigeration.

The containers used for aseptic packaging are typically made of materials such as cartons, bottles, or pouches. These packaging materials undergo a sterilization process to eliminate any microorganisms present on their surfaces. The sterilization techniques can include heat treatment, chemical sterilization, or a combination of both.

The post The Science Behind Ultra High Temperature (UHT) Milk appeared first on The Food Untold.

During the ancient times, our ancestors consume milk in its fresh form. Today, milk comes in many forms. This is due in large part of various processes that it may undergo. Some of these include pasteurization, fortification, bleaching, and homogenization. And it is indicated on the packaging or container if the milk has gone any of these processes. The words “pasteurized” and homogenized” are most common. So what is homogenized milk, anyway?

The process of homogenization started in Europe when it was invented in 1899 by French inventor August Gaulin. When the process was introduced in North America in 1909, the reception was lukewarm. But the public eventually accepted homogenized milk nearly 20 years after its introduction.

The primary purpose of homogenization is to prevent creaming, or the rising of fat to the top of a milk container. To do this, the size of the fat globules is decreased while increasing their number to make them evenly distributed throughout the milk. The homogenization technique permanently emulsifies the tiny fat globules by pumping milk under high pressure at 2,000 to 2,500 lb/in.2 (psi) through small mesh orifices in a homogenizer, a machine that creates a uniform and even mixture.

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The homogenized milk introduced in America in 1909 was made by a Gaulin homogenizer and milk sterilized in bottles at 226°F (108°C) for 20 minutes. This early form of a homogenizer consisted of a three-piston pump that pushed a mixed stream of milk and cream through tiny capillary tubes or valve.

If properly performed, homogenization gives milk a more homogeneous composition, better body and texture, a whiter look, richer flavor, and more digestible curd.

HOW HOMOGENIZATION WORKS

Homogenization provides permanent emulsification. This is due to the fact that as the surfaces generate new fat globules, each fat globule is covered with a portion of the lipoprotein membrane as well as extra proteins from casein and whey. As a result, these proteins adsorb onto the newly formed oil surface. This prevents globules from rejoining or coalescing and ensuring that fat is evenly distributed throughout milk.

Milk fat globules range in diameter from 1 to 10 microns when fresh from the cow. Following homogenization, the globules range in diameter from 0.2 to 2.0 m. Raw milk is homogenized by forcing it under pressure through very small diameter nozzles. Large milk globules are driven through an opening. This makes the membranes to shear, essentially breaking the tough globule coverings while mixing and forming many smaller fat globules. If the protein surface load is still low, the frequent collisions between newly produced drops could lead to recoalescence.

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The exposed lipid droplets are immediately covered by casein proteins from the milk’s liquid phase. As a result, casein-coated milk fat globules are smaller and less prone to separate from the rest of the milk. The negative charge of the casein proteins prevents milk fat globules from combining and forming a solid layer of fat.

Homogenization is most efficient when the fat phase is liquid, and temperatures between 140°F (60°C) and 158° (70°C) are typically used. A rise in temperature results in a little reduction in particle size. A temperature so low is not good either as it makes part of the fat crystalline.

Milk can be homogenized before or after pasteurization. The homogenization procedure is conducted quickly to ensure bacterial control and quality loss.

WHY HOMOGENIZED MILK?

When buying milk, it may be confusing as to which form to get. But is homogenized milk for you? It depends. Prevention of creaming is the main purpose of homogenization. But there are other benefits as well.

If you are someone whose stomach has a hard time digesting milk, Then homogenized milk is for you. Since its fat globules have been broken down into smaller particles, homogenized milk can be consumed without having an upset stomach afterwards.

Homogenized milk also has a whiter appearance than a non-homogenized milk. This is generally more acceptable than milk that is cream in color. This white color of homogenized milk is because of more evenly distributed fat. Due to the smaller fat particles, there is an increase in light absorption and reflection.

Some milk gets its white appearance because of bleaching. Bleaching is a process that makes milk white by treating the carotenoid or chlorophyll pigments with compounds such as benzoyl peroxide (BP). The Food and Drug Administration (FDA) permits the use of BP as a bleaching agent in milk, or in a mixture with potassium alum, calcium sulfate, or magnesium carbonate. But if you want white milk without such compound added, get homogenized milk.

The use of homogenized milk also has several disadvantages.

The production of any product that depends on the aggregation and gelation of the caseins, such as rennet curd formation or acid gelation in fermented milk, yields a final product that differs from equivalent foods derived from unhomogenized milk in terms of rheological and textural characteristics.

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The fat globules are also more prone to lipolysis when active lipase is present and to light-induced oxidation, both of which can be easily avoided by opaque packing.

The post What Is Homogenized Milk? appeared first on The Food Untold.

Milk without addition of any ingredients or additives is already rich in important nutrients, especially calcium. Milk in its pure form was the norm when our ancestors began consuming milk from animals. Fast forward to modern food industry, processes such as drying, pasteurization, homogenization, or fortification create products with different texture, taste, nutritive value, and shelf life. Pasteurization is a breakthrough in the milk industry as it makes milk safer to consume. Fortification is another important process in milk. Along with pasteurization, fortification became widespread in the early 20th century. It began in the 1920s when iodine was added to table salt to prevent goiter among children in the United States.

Fortification is the addition of micronutrients that were not originally there in the food. This helps reduce health risks while increasing the nutritional value of the food supply and promoting public health. Some products of food fortification include fortified milk, cereal, fruit juices, salt, and bread. Milk is commonly fortified with fat-soluble vitamins A and D. To put it simply, fortified milk is milk with added micronutrients (vitamins A and D) not commonly found in significant amounts.

Milk is naturally low in these vitamins, especially if milk contains no fat. Whole milk naturally contains vitamin A in its fat, and more vitamin A may be added before it is sold. For the milk to be nutritionally equivalent to whole milk even if it is reduced fat, low fat, or even skim milk, vitamin A fortification is required.

Since vitamin D is found in small amounts in whole milk naturally, it is often fortified. However, due to the cow’s ability to synthesize vitamin D when exposed to sunlight and the possibility that vitamin D may be present in animal feed, vitamin D to some extent is present in milk.

VITAMIN A & D IN FORTIFIED MILK

Micronutrients are so-called because our body needs them in small amounts. However, they are equally as important as macronutrients. Micronutrient deficiency may lead to serious health problems such as goiter. Micronutrient deficiency is a global health problem. For this reason, governments require certain foods to be fortified. Fortification of whole milk with vitamin A and D is optional. But low-fat milk, nonfat milk, and low-fat chocolate should be fortified with vitamin A.

Vitamin A

According to the World Health Organization (WHO), vitamin A deficiency is one of the most common globally. This is especially true in developing countries. Vitamin A-deficient individuals may experience health problems such as night blindness, skin diseases, and certain infections.

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Since the human body cannot produce this vitamin, it must be obtained from food sources. Unfortified milk already contains significant amounts (37.7 IU per gram of fat) of vitamin A since the vitamin is associated with milk fat. However, low-fat and skim milks have less vitamin A due to the elimination of milk fat. There was a nutritional concern about the loss of vitamin A present in these products as the demand for low-fat and skim milk products surged in the United States. To address this issue, low-fat and skim milks are required to be fortified with vitamin A to the nutritional equivalent of the general milk standard.

Low or non-fat milk and chocolate milk must be fortified with 2,000 international units (IU) or 140 retinol equivalents (RE) of vitamin A per quart (often before pasteurization). For milk involved in interstate commerce, it is necessary.

Vitamin D

Fortification of milk with vitamin A was initiated in the 1940s. This was the result of the positive acceptance by the public when fortification of milk with vitamin D was started to be practiced in 1933.

Vitamin D is available in two forms: vitamin D2 (ergocalciferol) and vitamin D3 (cholecalciferol). A plant-based source of vitamin D is vitamin D2. When exposed to ultraviolet radiation, skin spontaneously produces vitamin D3. Vitamin D3 is what commonly added in food.

Our body needs vitamin D to maintain and regulate healthy levels of minerals, including calcium, phosphate, and others in the blood. The minerals, in turn, are used for a number of processes, such as bone mineralization, muscular contraction, nerve conduction, skin, and overall healthy cellular functioning. But rickets prevention was the main reason why vitamin-D fortified milk was introduced. Since then, the disease is now rare, especially among children. Rickets is a skeletal disease in which the bones become soft and deformed. This develops from lack of vitamin D intake and exposure to sunlight.

Although it is not required, adding vitamin D to attain levels of 400 IU per quart is practiced. However, evaporated milk is required to be fortified with vitamin D.

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Aside from fortified milk, other common sources of vitamin D include oily fish, oysters, cheese, eggs, butter, and cream.

The post What Is Fortified Milk? appeared first on The Food Untold.

Raw milk is rich in nutrients—the primary reason why is it one of the highly perishable food items. To give you an idea, raw milk in the refrigerator may only last for only several days (7 to 10 days). Without subjecting it to high heat, raw milk may contain harmful microorganisms, particularly pathogenic bacteria. Pathogens such as Salmonella, E. Coli, and Campylobacter are commonly found in raw milk. Drinking contaminated milk may cause serious illness or even death.

For this reason, raw milk is tightly regulated anywhere in the world. In the United Kingdom (UK), consumers can only purchase raw milk directly from registered milk farms, direct online sales, and farmers at registered farmers’ markets. Scotland has completely banned the sale of raw milk. In the United States, the Food and Drug Administration (FDA) has prohibited the interstate sale of raw milk since 1987. Today, raw milk comes from highly hygienic farms where infections are rare, due in large part of the laws that exist.

Raw milk is meant for immediate consumption. But what about milk unrefrigerated on the shelf and in the refrigerator at the supermarket?

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Heat treatment makes it possible for milk to be stored this way. Heat destroys the pathogenic bacteria that may be present in the milk, extending its shelf life. This more shelf life stable form of milk is what the most of us consume. But if you frequent your local supermarket for your dairy supplies, you might have noticed that milk usually comes in two forms according to heat treatment: UHT (Ultra High Temperature) milk and pasteurized milk. But what exactly are the differences between UHT and pasteurized milk?

Let’s find out.

UHT vs Pasteurized milk

Basically, both forms of milk have been heat treated in a process called pasteurization. By definition, pasteurization is the partial sterilization of a product In order for it to be safe for human consumption. This process was named after the French scientist, Louis Pasteur, after he discovered that microorganisms are responsible for the souring of alcohol. By heating the beverage and then quickly cooling it destroy the bacteria and thus extending its shelf life. Today, many food items go through pasteurization including syrups, juices, eggs, beer, and milk.

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In dairy milks, there are basically three levels of processing—raw milk, pasteurized, and ultra-heat treated (UHT) milk.

Pasteurized milk is milk treated to a high temperature of 162°F (72°C) for 15 seconds. This heat is sufficient to eliminate the pathogens that may be present in the milk. While the duration of the treatment makes it possible to preserve the flavor, it starts to decline after several days. Under proper refrigeration, pasteurized milk can last for up to 3 weeks.

However, it is advisable to consume pasteurized milk before its expiration date written on the label. In the US, the storage temperature for raw and pasteurized milk must be maintained to 45°F (7°C) or lower.

UHT milk, on the other hand, is more shelf-life stable than pasteurized milk. UHT-treated milk is milk that has undergone a high temperature of 284°F (140°C) for 4 seconds. This destroys virtually all the microbes, spoilage enzymes, and unfortunately, the good bacteria (probiotics). And since UHT uses a temperature twice as high as that of pasteurized milk, UHT does not necessarily have to be heated for quite as long. UHT milk sealed in an aseptic packaging can last for up to 6 months or longer even if stored without refrigeration. This answers why milk on the supermarket shelf does not easily go bad.

Are these two better than raw milk?

It depends. Quality-wise, nothing beats raw milk. It it full of flavor, richer, and more creamy. Because it does not undergo any heat treatment, it retains its components, especially proteins, making it ideal for cheese processing. Studies have also revealed that raw milk contains more bioavailable nutrients, probiotics, as well as beneficial enzymes.

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Obviously, the only downside of raw milk is its perishability. Raw milk is highly perishable—It lasts only 7 to 10 days. Plus, it starts losing flavor after one day. So if you are going for raw milk, make sure it is consumed immediately.

While heat treatment allows milk to be stored safely for longer period, it is worth noting that heat alters the quality of milk, especially the nutrients and taste. This is especially true for UHT milk. The temperature it uses denatures the active protein, which degrades further during storage. Moreover, the calcium becomes insoluble. This means our body will have a harder time absorbing the bone-strengthening mineral after heat treatment.

Another disadvantage of UHT is milk is its altered taste. The ultra-high temperature affects the sugars in the milk, prompting caramelization to occur, reducing the creaminess, and giving the milk a burnt taste. When talking about convenience, UHT milk is a clear choice as it can reach distant places without spoiling. (UHT milk, by the way, is the most dominant form of milk in Asia.)

But if you have a fridge at home and are wary of the safety of raw milk, it is better to go for pasteurized milk. Its shelf life is long enough, and its quality is comparable to that of fresh raw milk.

The post UHT And Pasteurized Milk: What’s The Difference? appeared first on The Food Untold.