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Milk, often called nature’s most complete food, is the sole base on the basis of which the dairy industry forms one of the most vital components of the agricultural and food sectors worldwide. India, being the largest producer of milk, plays a central role in global dairy development and innovation. The continuous growth of this sector has contributed to nutrition and food security, and also provided sustainable livelihoods to millions of farmers. This book, “Textbook on Market Milk,” presents a comprehensive overview of the principles, practices, and processes involved in milk handling and processing. It aims to serve as a practical guide for students, teachers researchers, and professionals in dairy science, veterinary, and food technology disciplines. Beginning with the status and scenario of the dairy industry in India and abroad, the book details stages of milk collection, transportation, reception, and pretreatment. It discusses in detail the preservation of raw milk, role of natural inhibitors, and key technological processes such as homogenization, pasteurization, UHT and sterilization. Further chapters focus on special milk types, market milk, and distribution systems, ensuring a clear understanding of both traditional and modern milk processing techniques. The concluding section highlights the nutritive value of milk, emphasizing its importance in human health and nutrition.

Dairy Industry in India Milk holds a deeply symbolic place in Indian culture, far beyond its role as a mere food item. It is intricately woven into the cultural and historical identity of the nation, with the dairy industry serving as a cornerstone of India’s economy. The sector is a driving force behind rural development providing a crucial pathway to prosperity for millions of small-scale farmers. It plays a significant role in alleviating poverty and generating employment opportunities. The dairy sector by empowering farmers, developing modern infrastructure embracing technological advancements, and promoting sustainable practices, fostering widespread socio-economic progress in rural India. In the 1920s, modern milk processing and marketing technologies were introduced in India. The National Dairy Development Board (NDDB; founded in 1965), implemented Operation Flood (1970-96) to modernize the dairy sector through cooperatives. This led to the rise of dairy cooperatives countering the exploitation by private milk plants. The cooperatives followed the Anand model, a three-tier structure comprising village-level societies (producers), district-level unions (milk collection and processing), and state-level federations (marketing). Originating in Anand, Gujarat in 1946, the model was later adopted nationwide. The progress termed as White Revolution transformed India from a nation struggling with milk shortages into the world’s largest producer and consumer of milk. By 1997, India became the global leader in milk production with a volume of 70.9 million tons, surpassing the United States (FAO data rearranged by Our World in Data). Further in the year 2014, for the first time, it beat the entire European Union. Since 1950, India’s milk production has seen tremendous growth, rising from 17 million tonnes in 1950-51 to 230.58 million tonnes in 2022-23. The per capita availability of milk increased from 124 g/day in 1950-51 (PIB 2022) to 459 g/day in India during.

Introduction Similar to the procurement of raw materials in a factory, milk collection is one of the initial and essential steps for a milk processing or marketing company. A successful milk collection system combines efficient route planning, quality control, and effective farmer engagement. By prioritizing technology integration, cold chain management, and regulatory compliance, dairy companies can establish a reliable and sustainable milk procurement system that meets both operational and quality standards. India dairy sector depends on smallholder individual milk producers, each contributing between one to a few litres of milk per day. Typically, milk production takes place in rural areas, while the demand is concentrated in urban centres. However, rural producers often face significant marketing challenges due to the dispersed nature of milk production, scattered settlements, and inadequate supply infrastructure. Therefore, milk needs to be collected, transported, and marketed from villages to cities to ensure profitable returns for producers. Milk is usually collected from producers at designated collection points in rural areas, which serve a large number of small suppliers. This approach minimizes the need for individual chilling and storage facilities. Collection points should follow the same hygiene standards as dairy processing facilities. Milk should arrive at a chilling station within four hours of milking, especially in warmer climates. There, it must be quickly cooled to below 4°C to preserve its quality. Bulk milk coolers of required capacity are installed for the chilling and storage of milk at low temperature till it is transported to the processing plant.

Introduction Milk reception at the processing plant is a crucial stage in the dairy supply chain, as it serves as the first point of quality control and the gateway to further processing. The success of milk processing hinges on the careful handling, evaluation, and preparation of the raw milk upon arrival. The stringent protocols at reception ensure that only high-quality raw milk enters the system. By implementing advanced technology, strict hygienic standards, and efficient handling practices, processing plants can maintain milk’s safety and quality, setting the foundation for the production of superior quality dairy products. The intricate procedures at this stage safeguard consumers' trust and ensure compliance with regulatory requirements. Milk is transported to dairy plants either in cans or in road/rail tankers. The designated area within the dairy plant where milk is first received, inspected, and graded for acceptance is referred to as the milk reception dock, platform, or raw milk receiving dock (RMRD). This reception dock is specifically designed and equipped to ensure the efficient handling of milk, enabling its swift unloading while also accommodating the cleaning and sterilization of used containers. Since the quality of milk is a critical factor for its subsequent processing, the decision to accept or reject milk must be made promptly upon its arrival, following a thorough evaluation. The milk reception process should be meticulously planned, and the equipment must be selected to ensure efficient intake operations, particularly in facilities handling large milk volumes. Any delay can result in deterioration of milk before unloading, increased labour requirements, and higher operating costs. To avoid such issues, milk deliveries should adhere to a strict schedule, and the reception process should be completed within a stipulated time frame of time. This ensures seamless continuity of the dairy plant operations.

Preservation of raw milk is essential to maintain its quality during storage and transportation before processing. One of the primary methods for extending its storage life is refrigeration, where milk is cooled to 2°C to 4°C immediately after milking. This significantly slows down the microbial growth and enzymatic activity. Bulk milk coolers (BMCs) are vital in achieving rapid cooling, especially in collection centres or dairy farms, where they ensure that milk remains fresh during storage and transportation. BMCs are particularly essential for regions with inadequate cold chain infrastructure, as they help maintain milk quality until it reaches processing facilities. In addition to refrigeration, thermisation is another method used to preserve raw milk. Thermisation, a mild heat treatment, is widely used to extend the shelf life of raw milk, particularly when it needs to be transported over long distances. This process involves heating the milk to 57–68°C for 15 seconds, effectively reducing the microbial load while preserving the milk’s natural characteristics. Thermisation is typically followed by refrigerated storage, where milk is cooled to temperatures between 2° and 4°C to inhibit further microbial growth. The combination of thermisation and refrigeration ensures that milk retains its freshness and safety until it reaches processing facilities, even in regions with extended supply chains. Raw milk also benefits from its natural inhibitors, such as lactoperoxidase, lactoferrin, and immunoglobulins, which exhibit antimicrobial properties and slow down bacterial growth. The lactoperoxidase system, for instance, can be activated by adding small amounts of hydrogen peroxide and thiocyanate to enhance milk’s preservation in the absence of refrigeration. The use of chemicals like hydrogen peroxide (H2O2) for milk preservation is not permitted in India due to safety and quality concerns. However, the FAO recommends its application under strict regulatory conditions in some countries as part of the lactoperoxidase system, particularly in regions where refrigeration is unavailable.

Homogenization is now a widely used industrial process in dairy production, essential for stabilizing milk and other liquid dairy products. Its main purpose is to prevent fat from separating out of the milk, ensuring a smooth, consistent, and uniform product. Milk is a complex emulsion comprising water, fat, proteins, carbohydrates, minerals, and vitamins. Among these constituents, fat plays a critical role in determining the texture, flavor, and overall sensory quality of milk and dairy products. In its natural state, milk fat exists in the form of globules of varying sizes, surrounded by a thin membrane that stabilizes them in the aqueous phase. These fat globules typically range in size from 2 to 10 μm and have a lower density than the surrounding water-based phase of milk. This difference in density causes the fat globules to rise and form a cream layer when milk is left undisturbed, leading to an uneven texture and separation during storage. Homogenization is a mechanical process applied to milk to modify fat globules by forcing the milk under high pressure through a tiny orifice. This reduces the average size of the fat globules while increasing their number and surface area. Practically, this greatly minimizes the tendency of fat globules to rise and form a cream layer. The enhanced stability of homogenized milk is due to three key factors: the reduction in the average diameter of fat globules, as described by Stokes’ Law, which slows their upward movement; the uniformity in size distribution, which ensures globules rise at similar speeds, preventing clustering; and the increased density of fat globules caused by the adsorption of a protein membrane, bringing their density closer to that of the surrounding liquid. Additionally, heat pasteurization complements homogenization by breaking down the cryo-globulin complex, which otherwise promotes clustering and cream formation. The smaller and uniformly dispersed fat globules create a smoother, creamier texture and enhance the mouthfeel. This process also contributes to the visual appeal of milk, making it appear whiter and more uniform. Homogenization is, therefore, an essential step in modern dairy processing, ensuring the stability, quality, and consistency of milk and other dairy products, while addressing the challenges posed by the inherent properties of milk fat and its lower density.

Introduction Heat treatment is the most commonly used method in the dairy industry for milk processing. Its primary objective is to eliminate pathogens and reduce spoilage-causing organisms, ensuring milk is safe for consumption and has a longer shelf life. While advanced methods like high-pressure processing, pulsed electric fields, ultrasound processing, cold plasma treatment, and ultraviolet sterilization have emerged, heat treatment remains the preferred choice due to its simplicity, reliability, and proven effectiveness. All dairy products undergo some form of heating during processing, whether through pasteurization, sub-pasteurization (e.g., for milk used in aged cheeses), or sterilization. To facilitate this, liquid heating systems such as continuous heat exchangers or jacketed tanks are widely used, typically powered by steam or steam-heated water. Consequently, steam generation boilers are a standard feature in almost all dairy processing facilities. The Key Objectives of Heat Treatment Include 1. Elimination of harmful pathogens in milk, ensuring it is safe for consumption and protecting public health. 2. Increasing the keeping quality of milk by reducing the number of spoilage organisms. 3. Inactivating enzymes naturally present in milk or secreted by microorganisms to prevent enzymatic degradation. 4. Preventing the autoxidation of lipids, which can lead to off-flavors and spoilage. 5. Inactivating agglutinin to reduce rapid creaming and maintain uniform consistency. 6. Enhancing the growth of starter cultures by eliminating natural inhibitors and dissolved oxygen in milk, essential for producing cheese and fermented products.

Introduction and Relevance UHT processing of milk was developed to produce a shelf-stable product with minimal chemical changes as encountered with sterilized milk. Aseptically packaged UHT milk can have a shelf life of 06 to 12 months and does not need to be stored in a refrigerator. Its role in the market varies by region. In countries like the India, USA and Canada, where UHT milk occupies a smaller segment of the liquid milk market, it is often used as a backup option, reserved for situations when pasteurized milk is unavailable. Conversely, in regions such as Europe, (particularly France, Belgium, Spain and Germany), Asia, (China, Japan, Thailand and Vietnam) Latin America and (Brazil) in UHT milk is the dominant form of milk available and is consumed regularly. In markets where it is a backup option, UHT milk requires long-term stability of 6–12 months, while in regions where it is used daily, a shorter shelf life of three months or less is often sufficient. Ultra-High Temperature (UHT) treatment involves heating milk to very high temperatures, typically between 130°C and 150°C, for a brief period of few seconds. This process results in commercially sterile milk, meaning that while not all bacteria are destroyed, those capable of growing under ambient storage conditions are effectively eliminated. An essential component of UHT processing is aseptic packaging, where the sterilized milk is filled into presterilized containers in a sterile environment. This combination ensures that the milk remains free from contamination and maintains its extended shelf life without requiring refrigeration. Standards for UHT processing vary globally. In the European Union, a minimum temperature of 135°C with an appropriate holding time is mandated. In the United States, the standard for ultra-pasteurization is 280°F (137.8°C) for 2 seconds. Many international standards recommend 135°C for at least 1 second, though some countries do not specify minimum conditions. However, this level of treatment is often regarded as insufficient for completely destroying the spores of spoilage organisms, highlighting the importance of precise temperature-time combinations and the critical role of aseptic packaging in ensuring product safety and stability.

Sterilization is a thermal process aimed at destroying all microorganisms and microbial spores in milk, ensuring the product is microbiologically safe and shelf-stable at room temperature for extended periods. It is primarily used in the production of sterilized milk and evaporated milk, with typical conditions involving heating at 116°C for 15 minutes. This process kills all microorganisms and also inactivates all milk enzymes, including plasmin, which might otherwise contribute to spoilage during storage. However, enzymes produced by psychrotrophic bacteria should not be present in raw milk, as they are highly heat-stable and may remain active even after sterilization. Sterilized milk can be stored at room temperature for longer period. Sterilization kills all microorganisms and inactivates all microbial spores that may germinate under the storage conditions of the product in the market. The Food Safety and Standards Authority of India (FSSAI) define “sterilization” in relation to milk and milk products as the process of heating the product in a sealed container continuously to at least 115°C for 15 minutes. This treatment ensures that the milk can be preserved at room temperature for a period of not less than 30 days. In-bottle sterilised milk is a shelf-stable dairy product produced by sealing milk in glass bottles and subjecting it to high-temperature heat treatment. Typically, the milk is heated to temperatures ranging from 110°C to 121°C for 15 to 30 minutes. This process effectively destroys all vegetative microorganisms and bacterial spores, making the milk microbiologically safe and extending its shelf life up to 6–9 months without refrigeration. The heating is usually done in batch retorts or autoclaves after the milk has been bottled and sealed. Although the process ensures safety, it often leads to a slight cooked flavour and some nutritional losses, particularly in heat-sensitive vitamins such as vitamin B1 and vitamin C.

Introduction Market milk holds a crucial place in human nutrition, economic development, and the dairy industry. Its consumption patterns and marketing strategies continue to adapt, influenced by evolving lifestyles, consumer preferences, and advancements in processing and packaging technologies. Regulatory frameworks ensure its safety and quality, while the wide range of milk types caters to diverse dietary and cultural requirements around the world. Modern dairy farms rely on advanced milking machines that prioritize both efficiency and hygiene. These machines use vacuum-operated devices to gently extract milk from cows’ teats without causing discomfort. The collected milk is immediately transferred into refrigerated tanks to maintain its freshness and prevent bacterial growth. Speed and efficiency in transporting milk to processing facilities are critical to ensuring its safety and quality. At the processing plant, milk undergoes standardization, an essential step where the fat content is adjusted to produce different types of milk, such as whole milk, toned milk, double-toned milk, and skimmed milk. This ensures uniformity in fat levels, meeting market specifications and regulatory standards such as prescribed by FSSAI in case of India. The milk then undergoes pasteurization, a process of heating it to a specific temperature for a defined period to eliminate harmful bacteria while preserving its nutritional value. Pasteurization has significantly improved milk safety, reduced health risks, and extended its shelf life. Following this, the milk is homogenized, where fat molecules are evenly distributed to prevent cream separation. This centres a smooth texture and consistent flavor preferred by consumers.

Introduction Special milks, a dynamic segment of the dairy industry, cater to diverse consumer needs through products like flavored milk drinks, lactose-reduced or lactosefree milk, micronutrient-fortified milk (e.g., vitamin- or iron-enriched), and protein-enhanced milk. This segment is experiencing significant growth, driven by health-conscious consumers, increasing lactose intolerance awareness, and demand for functional and fortified foods. Globally, the market for fortified and specialty milks is projected to grow at a compound annual growth rate (CAGR) of over 6% by 2030. While flavored milks dominate in terms of appeal to younger demographics, fortified milks, particularly those enriched with vitamin D and calcium, cater to aging populations and health-conscious individuals. The economics of special milks are appealing for producers, with higher price premiums compared to regular milk. Niche areas, such as proteinenriched milk for athletes, lactose free milks for lactose intolerant persons, and low-sugar variants for diabetics, are gaining traction, reflecting evolving consumer preferences for tailored nutrition. This sector’s growth underscores a shift toward personalization in the dairy market, supported by innovations in processing and packaging to retain nutritional quality and extend shelf life. Flavored Milks Milk drinks are products ready for consumption, made from milk with differing fat contents and additions such as sugar, cocoa, fruit concentrates, coffee, flavors and/or other food ingredients, which are homogeneously mixed and contribute to flavor and taste. Flavored milks of various types are manufactured on the basis of whole milk, fat-reduced milk or skim milk (<0.5% fat). They are marketed in the form of pasteurized, UHT or sterilized products. These beverages promote milk consumption by offering a flavorful alternative to plain milk, especially for those who are reluctant to drink regular milk. Studies showed that providing flavored milk in schools significantly boosts milk intake, thereby enhancing the consumption of essential nutrients like calcium, protein, and vitamins among children.

The distribution systems are designed to ensure that processed fluid milk is stored and transported under optimal conditions, maintaining its quality and freshness until it reaches consumers. An effective distribution system for processed fluid milk involves careful planning and execution to guarantee timely delivery, quality preservation, and customer satisfaction. Given that milk is a highly perishable product, it requires meticulous handling and strict temperature control. Technology plays a crucial role in preserving its integrity throughout the supply chain. The use of technology reduces human error, increase the efficiency of distribution operations, and lower operational costs by preventing idle resources through coordinated logistics for both outbound and inbound trips. To address the specific demands of manufacturing, packaging, distribution, and transportation, integrated business process automation solutions are implemented. These solutions include following features: • Identify and define the most efficient delivery routes, reducing transportation costs and ensuring timely delivery. • Scheduling and monitoring of delivery routes to maintain optimal delivery speeds, and manage loading and unloading processes so as to minimize exposure to adverse conditions. Automated solutions and tools help maintain the required temperature conditions throughout the entire supply chain. • Verify and document supplier practices to ensure that all partners in the supply chain adhere to the agreed-upon temperature standards. Store the temperature-related data to help in auditing and analysis, and continuous improvement of the cold chain process. • Shelf life and expiration date management is a critical component in  the storage and transport of dairy products. Proper management ensures that dairy products remain safe for consumption and retain their quality throughout the distribution chain.

Milk: Composition, Nutritional Role, & Importance for Human Health Introduction Milk is one of nature’s most complete and balanced foods, offering a rich source of essential nutrients such as proteins, fats, carbohydrates, vitamins, and minerals in forms that are easily digested and assimilated by the body. It serves as a cornerstone of human nutrition, providing critical support for growth, bone strength, and overall health. Known as the nectar of life, milk not only sustains life but also enhances immunity, forming the first bond between mother and infant. An adequate intake of calcium, particularly during childhood, is critical for bone development and preventing osteoporosis in later life. Rich in calcium, phosphorus, and vitamin D, milk is vital for maintaining strong bones and teeth while preventing osteoporosis. Its high-quality proteins support muscle growthand recovery, while lactose and fats provide both immediate and sustained energy. Micronutrients like zinc, selenium, and whey proteins strengthen the immune system, and its high water content makes milk an excellent source of hydration. These qualities make it a protective food for all age groups, from infants to the elderly. While milk naturally lacks iron and has low levels of vitamin D, fortification with additional nutrients enhances its nutritional profile, making it even more beneficial. Fortified milk helps address deficiencies, supports bone health, and boosts immunity, making it an ideal dietary option for diverse populations. For infants and children, milk is a near-perfect food, and for adults, it serves as an excellent dietary supplement, particularly for its calcium, protein, and vitamin content. Beyond its nutritional benefits, milk plays a significant role in culinary traditions and cultural practices across the globe.