Preface Dairying is an integral part of the diverse system of agriculture that prevails in India and therefore, plays a vital role in agricultural economy and food production of the country. It provides essential food value in the form of milk and milk products to the millions of the country’s inhabitants. Dairying is the major source of income for the rural masses, as about 70% of the population comprises of small, marginal and landless farmers who benefit directly from dairying activities. India has about 15% of the global cattle population, 56% of the world’s buffalo population and accounts for 15-16% of the word’s annual milk production. The growth in milk production is about 4%. India stands tall among the milk producing countries with an annual production of about 120 million metric tons, though the organized sector handles only about 30% of the total milk produced. The initiation and development of the dairy co-operative enterprise paved the way for increased milk production and handling. India currently has more than 133349 village dairy cooperatives federated into 177 milk a systematic manner requires entrepreneurial skills, managerial experiences and proficiency in manufacturing. The dairy researchers in the country have contributed immensely to the exponential growth of the dairy enterprise. However, they cannot rest on their laurels and need to explore, disseminate and promote newer areas of knowledge. Novel tools, equipments, techniques and technologies are the need of the hour for edging the dairy enterprise towards greater success. Thus, Human Resource Development in dairying will encompass a thorough understanding of the basic theory accompanied by skillful application of that knowledge on the shop floor with the correct attitude towards experimenting with and introducing new ideas and techniques for constant improvement. The authors with their strengths of academics and research in the discipline of Dairy Technology have been involved in developing manpower for the dairy industry and imparting training at an Institute of national repute. This book is the result of their strong feeling of the need to compile information and integrate traditional and novel technologies that exist worldwide in the processing of liquid milk. The book has been organized in various chapters that include the history of dairy development in India, procurement and consumption pattern of milk, processing, quality assurance and packaging of fluid milk products and food safety laws. The authors hope that this work will serve the students of Dairy Technology in the country and also provide a ready reference to the teachers involved in shaping the human resource needs of the Indian dairy industry.

1.1. Introduction The significance of milk as the most wholesome single food available in nature has never been debated. It is as ancient as mankind itself, as it is the substance created to feed the mammalian infant. All species of mammals, from the lowly rat to the mighty whale, produce milk for this purpose. Several centuries ago, perhaps as early as 6000-8000 BC, ancient man learned to domesticate species of animals for obtaining their milk for consumption. These included cows, buffalos, sheep, goats and camels, all of which are still used in various parts of the world for the production of milk for human use (Fig. 1.1 & 1.2).

Milk is the secretion of the mammary glands of animals. For human consumption, milk is that liquid obtained from the cow or the buffalo during the period following at least 72 hours after calving or until the milk is colostrums-free. It is a complex biological fluid consisting of seven main components: water, fat, protein, sugar (lactose), minerals, vitamins and enzymes. Milk is a white opaque fluid in which fat is present as an emulsion, protein and some mineral matters in colloidal suspension and lactose together with some minerals and soluble proteins in true solution. The opacity of milk is due to its content of suspended particles of fat, proteins and certain minerals. The colour varies from white to yellow depending on the carotene content of the fat. Skimmed milk is more transparent with a slightly bluish tinge. Milk of a good flavour has a pleasant, slightly sweet taste, and no odour. It is an excellent source of calcium, phosphorous and riboflavin. Vitamin A and D are currently added to whole milk, partly skimmed and skimmed milk.

Milk production in India is a subsidiary activity of agriculture in contrast to the organized dairy sector in the western countries. Farmers and landless labour maintain one to five milch animals. As a result, small quantities of milk are produced in a scattered manner. Due to this reason, milk procurement models from western countries, such as bulk cooling and bulk transportation are not applicable under Indian conditions. Collection of small amounts of milk is scattered over long distances and, therefore, poses a formidable challenge in maintaining the quality attributes and keeping costs down. 3.1. Rural Milk Collection A systematic approach to rural milk collection suitable for the tropical climate and techno-economic conditions prevailing in India has been developed, based on the indigenous experience gained over the past few decades. In the first phase, extensive surveys are undertaken in the milkshed areas, where the milk plant is to be established. The second phase involves ‘route planning’ taking into account, availability of quantities of milk, access to roads for plying vehicles and distance from the site of dairy plant. Then zones are identified, representing equal costs of collection and transportation. In the third phase, planning is done for locating the primary collection centres as well as chilling centres, where, milk can be cooled to 4ºC before transporting to the milk plant. Milk may be collected from individual producers either by the contractor or by forming village level cooperative societies.

Milk, on reception at the dairy factory is subjected to various unit operations on its way to product manufacture. Processing is applied as a means to convert liquid milk into products or to render the milk (and products) safe from harmful organisms. The basic processing operations to which milk is subjected at processing units have been described in this chapter. The common processing operations employed are depicted in Fig. 4.1. Several of these operations are routine compulsory processes common to all dairies, while certain others are undertaken for specialized purposes in some dairies. 4.1. Filtration and Clarification At the time of milking various foreign materials such as dirt, feed, manure, dandruff, hair, flies, dust particles, worn out cells, cell debris and many other undesirable substances may find their way into milk. The process of removal of this extraneous matter (solid particles of higher density than that of milk) is called filtration or clarification. This can be achieved either by simple filtration through specially woven filter cloth or continuous process of centrifugal clarification that helps

Milk, as secreted in the udder of a healthy animal is practically sterile, but during its transit to the processing plant, becomes heavily contaminated with a variety of micro-organisms. These may be responsible for spoilage of milk or for causing diseases in animals and human beings. It thus becomes imperative that adequate heat treatment is given to milk to destroy these micro-organisms, thus increasing the shelf-life of milk as well as making it safe. Varied heat treatments offer the potential of producing different kinds of processed milk to satisfy the needs of the consumer. To cater to the ever-increasing demand of consumers, several varieties of processed milk are available in the market, some of which are discussed below. 5.1. Pasteurised Milk Pasteurisation was named after the renowned French scientist Louis Pasteur, who discovered that spoilage organisms could be inactivated in wine by applying heat at temperatures below its boiling point. The process was later applied to milk and remains the most important operation in the processing of milk. It is the process by which every particle of milk is heated to such temperature-time combinations (usually to 63°C for not less than 30 minutes or to 72°C for not less than 15 seconds) and promptly cooled to 4°C or below so as to destroy any harmful bacteria that may be present without affecting flavour and food value. Pasteurisation does not involve the use of any additives. Apart from making milk safe to drink, pasteurisation increases the length of time it can be kept before it spoils. The nutrient losses due to pasteurisation are so small, that they are considered insignificant.

Packaging is a tool that is used to contain the product, protect the product from environmental hazards and help in marketing the product. Examples of ideal natural packaging systems are that of a banana, orange, coconut and egg, where the packaging is provided by nature. The major step forward in the food processing arena has been the ability to protect and preserve products with packaging and hence ensuring the availability of fresh and processed products out of season and over long distances in various forms. Milk is a highly perishable product and is not uniformly available round the year to the whole country due to geographical and genetic variations. If dairy products are to be available all the year round the country, irrespective of the season and area, it must be presented in packages that are convenient to purchase and use. Packaging has additional responsibilities of providing convenience, safety and facilitating, besides handling, storage and distribution of products. It should prevent spoilage of food by microbial or insect attack. It also preserves the quality and nutritive value of many foods by the exclusion of oxygen and the control of moisture loss or gain. It increases the shelf-life and ensures longer availability and contributes to the product image through structural and graphic design. Product information is also given out through the medium of labeling, which acts as a tool for marketing and advertising.

Cleaning and sanitisation are the two processes employed in dairy industry to ensure hygiene and product safety. The safety of milk and milk products is a very important aspect and every attempt should be made, during processing, to minimize contamination through handling and processing equipments. The accumulated dried milk solids (milk stones) consist largely of calcium phosphate, milk proteins (precipitated, coagulated and baked on by heat) and insoluble calcium salts from water and washing detergents. The surface can also contain biofilms, which are formed by the incorporation of bacteria into the accumulated inorganic and organic materials that attach to most surfaces. With time and in the presence of nutrients, a biofilm and the bacteria within the biofilm will grow and become strongly attached to the surface. The removal of dairy soil, milk stones as well biofilms is the prime objective of the cleaning process. International Dairy Federation (IDF) defines a clean surface as one which is free from residual film or soil that will not contaminate the food products coming in contact with it. While cleaning refers to the removal of soil from the surface of the equipment, sanitisation implies destruction of all pathogenic and almost all non-pathogenic organisms. Cleaning and sanitisation are complimentary processes. Either of the processes alone will not achieve the desired result, which is to leave the surface as free as possible from soil and viable organisms. In actual practice cleaning and sanitisation overlap to some extent, as during cleaning a high proportion of bacteria are destroyed and others get removed in the detergent solution. Inadequate or faulty cleaning and sanitisation can have serious consequences, as milk is a prefect nutrient in which bacteria can multiply. A thorough understanding of the cleaning methods is, therefore, necessary for economic production of high quality food products.

India has achieved a commendable position of being the highest milk producing country in the world. Nearly 110 million tons of milk per annum is contributed by small and marginal farmers having 2-3 milch animals which are scattered in lakhs of villages across the length and breath of India. The poor socio-economic conditions are serious constraints in producing raw milk of good quality. The quality of milk is further deteriorated during subsequent handling and transportation. Milk being a product of biological origin, is extremely vulnerable to attack by microbes. It is also a good vehicle for additives and adulterants without any apparent changes in its appearance. Thus, milk is susceptible to several post-secretion changes, some natural and some man-made. Indian dairy industry faces a mammoth task to meet the world quality standards, particularly in the present context of globalization and increasing quality conscious consumers. In view of the highly perishable nature of milk soon after it is secreted, it is important to monitor its quality by having a firmly installed quality assurance programme along the entire production-to-supply chain. This can be possible with application of sensitive, accurate and rapid methodologies as a tool in quality assurance programmes. Quality comprises of several attributes ranging from physical, chemical, technological and bacteriological through nutritional to aesthetic. All dairy plants have a quality assurance laboratory (Fig. 8.1) and usually follow chemical quality control with the intention of payments to contractors/producers, processing of milk and meeting mandatory requirements for end products. Quality is judged both by objective and subjective tests.

The dairy processing industry in India deals mainly with the fluid milk and/or short shelf life products, despite India being the largest producer of milk in the world, with an output bordering the 110 million ton mark. This feature offers immense potential in the area of R&D in dairy processing in terms of value addition. The potential gains are many, including higher returns for producers and advantages in terms of health, therapeutic, nutritional and/or gastronomy for the consumers. However, the Indian Dairy Industry can amass possible benefits by being a global contender in trade only when its products are at par with those available in the rest of the world in terms of price and quality. It is evident from the post-WTO scenario that for sustainability, Indian dairy industry will need to maintain wholehearted commitment to quality management right from the farm to the consumer, shedding its inhibitions and resistance to changes. 9.1. WTO Agreements and Food Industry The General Agreement on Tariffs and Trade (GATT) was formed in 1947 and lasted until 1994, when it was replaced by the World Trade Organization (WTO) in 1995. The WTO is the only global international organization dealing with the rules of trade between nations. It provides a forum for negotiating agreements aimed at reducing obstacles to international trade and ensuring fair deal for all, thus contributing to economic growth and development. Currently, there are 16 agreements to which all WTO members are parties and two agreements to which only some WTO members are parties. WTO currently has 153 members, of which 117 are developing countries or separate customs territories. The Head Quarters of WTO is at Geneva (Switzerland) and the official languages are English, French and Spanish.

Index A Acidity 31, 62, 69, 100, 116, 160, 169, 196, 232, 233, 239, 240 Adulterants 79, 229, 235 Aflatoxin 263 Age gelation 40 Agglutination 30, 37 Agriculture Produce Grading 254, 255 Alcohol test 69, 232 Alcohol-alizarin test 232 Alkaline phosphatase 42, 43, 50 Alpha lactalbumin 38, 41, 42 Aluminum foil 185, 187, 189 Amino acid 37, 42, 55, 177 Amylase 42, 204, 206, 207, 222 Angular velocity 94 Antibiotic 243, 244, 245, 246, 250 APEDA 83 Ash 26, 27, 47, 48, 195, 200, 201, 216, 236