eChapters

Milk is a highly perishable commodity. The shelf life of raw milk is in hours. In order to harness its full potential for the well being of the humanity, it is essential to extend its shelf life not only in days but also in months and years. This can be achieved by judicious application of processing and preservation technologies.

Preservation is any purposeful treatment or processing of a food which prevents spoilage and extends the shelf life of raw material to a longer than its natural keeping quality.

During storage and distribution foods are exposed to a wide range of environmental conditions. Environmental factors such as temperature, humidity, oxygen and light can trigger several reactions that may lead to food deterioration. As a result foods may be altered to such an extent that they are either rejected by the consumer or are harmful to the person consuming them. It is, therefore, essential that the good knowledge of different reactions that cause food deterioration is gained prior to understanding the principles of food preservation.

The deterioration in foods may be caused either due to internal or external chemical or microbial reactions occurring in milk. The changes may be either latent to senses of consumer, or they may be discernible by the human senses. The consumer cannot perceive latent changes visually, olfactorily or otherwise, and laboratory measurements are the only method to detect them. Still the nutritional value of such materials may be seriously impaired. Such changes include fermentation, oxidation of lipids, loss of vitamins and changes in the contents and composition of nitrogenous substances.

Non-microbial changes in foods, perceptible to human senses, may often lead to serious deterioration noticeable to the average consumer. These include discolouration and changes in odor, taste and consistency. Microbial changes may result in alteration of original properties of milk making it unfit for further processing, deterioration in flavour quality, loss of nutrients and toxin production.

Membrane technology is a proven separation method used on the molecular and ionic levels. Since the beginning of the 1970s, this technique has been adopted by the dairy industry. Membrane separation is widely used in dairy processing plants to perform an ever-increasing range of duties, e.g. pre-concentration, partial demineralization, protein separation, bacteria removal, brine clarification and waste water recycling. Representing one of the great technological developments occurring within the dairy industry during the second half of the twentieth century, progress was driven initially by the transfer of know-how gleaned from the application of cellulose acetate-based reverse osmosis (RO) and ultrafiltration (UF) membranes in other industrial sectors to whey processing. Later, new membrane materials and engineering designs were built on this initial achievement and opened up further opportunities for the application of the full spectrum of membrane separation systems that also includes Nan filtration (NF) and cross-flow microfiltration The integration of these unit operations into traditional dairy processes has led to the development of innovative ingredients as well as improvements in yield, efficiency and product quality. R & D work indicates potential RO application for concentration of milk for products like khoa, condensed and dried milk products and of UF application for the manufacture of shrikhand, paneer, chana and cheese. Application of these processes permits higher energy saving, higher yields and superior product quality compared to traditional processes of thermal evaporation.

Packaging means a coordinated system of preparation of goods for distribution, storage, merchandizing and shipment at optimum cost compatible with the requirements of the product. It also includes the art, science and technique used, preparatory to and during transportations and selling of goods and technical methods and work processes related to the above preparations.

The broad range of dairy products necessitates that packaging equipment and materials encompass nearly all types from flexible to rigid and from high to low barrier. The general types of packaging and equipment are discussed below with a focus on fluid products but it must be recognized that other dairy products such as cheese have their own particular packaging requirements and technologies.

Role of packaging in distribution and sale: The essence of what makes milk and dairy products important source of human nutrition also causes rapid deterioration and high perishability. The major role of dairy packaging is to retard the deterioration by preventing microbial recontamination and excessive chemical deterioration. Fluid products are especially susceptible to microbial, enzymatic and chemical degradation. In addition to retarding quality loss, packaging must provide containment, facilitate use, identify products, communicate, and appeal to consumers, all with maximum production efficiency. The large volumes and low unit value means that these functions must be met with minimal economic cost and environmental impact. Because food packaging is generally highly regulated, legal requirements must also be understood and met.

When natural constituents of whole milk are altered by addition, removal, exchange and / or treatment, the resultant milk is designated as special milk. Recent years have witnessed a large increase in market penetration of special milks into the total fluid milk market. In many countries, now a large portion of fluid milk is consumed in the form of special milks. Manufacturers of special milks offer numerous advantages that are broadly related to dietary, cost and scarcity aspects. Special milks provide an avenue to diversify the milk with variety of flavours and other characteristics.

Milk is considered as nature’s almost perfect food. However, milk in its natural form is not considered suitable for many more healthy people who do not like the taste of milk as such. All these problems can be overcome by manufacturing special milks such as dietetic milks, low fat milks, flavoured milks, etc.

Butterfat is the most expensive constituent of milk. Therefore, the cost of buffalo whole milk is very high and many people particularly the weaker section of our society cannot afford to buy it. Consequently, manufacture of low priced toned milk was introduced in many markets. This also enabled the dairy plants to meet the ever increasing demand of milk, particularly during lean season. Replacement of butterfat by vegetable fat could also help in reducing the cost of milk

Due to seasonal fluctuation in milk production, there is acute shortage of milk during the lean period in our country. In certain parts of the world fresh milk is not produced at all. Manufacture of reconstituted and recombined milk from anhydrous milk solids can overcome such whole milk shortage. These anhydrous milk solids could either be prepared from the domestic seasonal surplus or marketed from those countries that have surplus milk production. The machinery and manpower of a market milk plant can be fully utilized all the year round by such diversifications.

Fat-rich dairy products such as cream, makhan, butter, butter oil and ghee have played a pivotal role in growth and development of dairy industry in India as well as abroad from the time immemorial. The reference of makhan and ghee has been found in old Indian scriptures. Makhan was popularized by Lord Krishna about 5000 years before. In the traditional Indian dietary regimen, milk fat in the form of malai (cream), makhan (freshly churned butter) contributes significantly towards nourishment of people of almost all ages.

Indian dairy industry, over the years, has been converting surplus milk for the manufacture of fat-rich dairy products, especially ghee and butter with skimmilk as a byproduct because of technological and economic reasons. More than one-third of the total milk production is being utilized for the production of ghee and butter wherein milk lipids, the most expensive constituents of milk are conserved and preserved. Milk lipids play many diverse roles, some of which are essential for human health. Many of the desirable flavour and textural attributes of dairy products are due to their lipid components, consequently, butterfat has, traditionally, been highly valued. Significance of fat can also be realized from the fact that the consumer’s perception of food quality is largely based on the perceivable rich taste. Unfortunately, milk lipids are subject to chemical and enzymatic alterations which can cause flavour defects referred to as oxidative and hydrolytic rancidity, respectively. The storage stability of high-fat products is strongly influenced by these changes.

2.1. The Story of Fermentation

Human progress depends on man’s tact to tame the forces of nature. It calls for knowledge. Prior to Age of Science, our fund of such knowledge was gained by a process of trial, error and accidental discovery. Progress was due not so much to man’s understanding as it was to his unquenchable spirit, miraculous ingenuity and indomitable persistence.

At last, in the utmost urgency of struggle for a longer, healthier and more satisfying existence, humanity taught itself the scientific method, which has changed the world, and will change it more in the coming years. This chapter deals with one of the most momentous and far reaching of all scientific achievements: the ability to harness microscopic living creatures in the service of mankind. Thanks to the wonders of fermentation technology and biochemical engineering developed by scientists and skilled technicians in industrial, governmental and university laboratories around the world, billions of microbes are now at work in industry, producing substances that give us better food $#x0026; drink, better clothing $#x0026; shelter and better medicines. Thus, the human race has entered a new era of health, comfort and longevity.

In the Beginning Art without Science: The cave man discovered that meat allowed to stand a few days was more pleasing to the taste than meat eaten soon after the kill. The cave man’s earliest descendants learned that intoxicating drinks could be made from grains and fruits.

Starter cultures were unknown until 1878, when Lister isolated pure cultures of the lactic acid bacteria responsible for milk acidification. In the 1980s, improvements to standardization and ripening of butter were made by introducing pure starter cultures. During the period 1910-20, Orla-Jensen, von Freudenreich, Sherman, Hammer and other dairy microbiologists prepared pure cultures for fermented milks. Commercial production and use of starter cultures grew rapidly and was widespread at the beginning of the 20^th century.

Dairy starters are the ‘heart’ of fermented milk products, the most crucial component in the manufacture of high-quality fermented milks. The cultures are harmless food-grade microorganisms, active bacteria intentionally grown in milk or whey or other formulated media which impart desirable and predictable flavour and texture to fermented dairy products.

The dairy microorganisms employed in milk fermentation are single-strain or multiple-strain cultures of lactic acid bacteria, producing different types of fermented milk products. Usually, one or two strains dominate the milk environment. Individual strains can be selected in advance for their resistance to both bacteriophages and antibiotics. Mixed starter cultures are used to ensure that fermentation will continue after a bacteriophage attack. Bacteriophages are highly strain-specific, and if the dominant strain in a mixed-strain starter culture succumbs to an attack, the phage-resistant mutant or the next dominant culture maintains a satisfactory rate of lactic acid production.

Cheese is a milk product of ancient origin and portrays the ethos of civilization and its cultural evolution. Cheese is one of the oldest foods of mankind. It is commonly believed that cheese evolved in the Fertile Crescent between the rivers Tigris and Euphrates in Iraq some 8000 years ago. The so-called Agricultural Revolution occurred here with the domestication of plants and animals.

It seems that the cheese originated accidentally as a result of the activities of nomadic tribes. Since animal skin bags were a convenient way of storing liquids for nomadic people, these were used for storing surplus milk. Fermentation of the milk sugars in the warm climate prevailing would cause the milk to curdle in the bags. The swaying animals would have broken up the acid curd during journeys, to produce curds and whey. The whey provided a refreshing drink on hot journeys, while the curds, preserved by the acid of fermentation and a handful of salt, became a source of high protein food supplementing the meager meat supply.

This activity gave rise to the assumption that cheese was evolved from fermented milks. It is perhaps more probable that the crude fermentations progressed in two ways. In one direction towards the production of liquid fermented milks such as dahi, yoghurt, laban, koumis and Kefir and in the other direction through the drainage of whey through a cloth or perforated bowls, to leave solid curds which when salted became cheese.

It was a prominent article of the Greek and Roman diet as much as 2500 years ago. It is referred to in the Old Testament several times.

Heat desiccated products represent khoa and khoa-based sweets, rabri, basundi, etc. These are important traditional dairy products. Traditional dairy products and a great assortment of sweets is an integral part of Indian heritage. These products are endowed with enormous value and enjoy tremendous mass appeal. Of great social, religious, cultural and economic importance these products have been developed over a long period of culinary skills and carry with them, the age-old wisdom and experience. Traditional dairy products have always played a pivotal role in preservation of precious milk nutrients and promotion of its consumption among masses. The increased availability of milk during the flush season coupled with lack of facilities to keep liquid milk fresh during transit from rural production areas to urban market has led to the conversion of milk into variety of traditional products. In addition to preservation of milk solids for longer duration, manufacture of traditional dairy products adds value to milk and also provides tremendous employment opportunity. It is estimated that about 50% of milk produced in India is converted into a variety of traditional products.

Traditional dairy products represent the most prolific segment of Indian dairy industry. These products not only have an established market in India but also have a great export potential because of strong presence of Indian diaspora in many parts of the world. In view of the growing awareness towards the safety aspects of milk-based sweets in India, the consumer shall prefer to buy these products from the organized sector. Despite the widespread popularity and acceptability of traditional milk products in the Indian market, the organized sector has so far not been able to tap into this market potential for many reasons such as lack of published literature on their technology, inadequacy of appropriate technologies for their commercial exploitation, inadequacy of appropriate packaging materials and labeling to take care of new pattern in consumer demand, low keeping quality and a lack of quality assurance systems.

Milk may be concentrated as a necessary initial step in drying operation or as concentrating step in the manufacture of sweetened condensed milk or evaporated milk or the preparation of infant formulae. In order to preserve the milk constituents in a concentrated form, condensed milk/concentrated milk is manufactured from whole skim milk by removing or evaporating part of the water under vacuum. But this form of milk still has limited shelf life. Attempts to prolong the shelf life of this product have been made through the addition of bacterial growth inhibitor like sugar (sweetened condensed milk) or by heat processing (evaporated milk) to destroy the microorganisms.

Concentrated milk industry is an important segment of dairy industry. It plays an important role in the economy of industry. It serves as a balanced economy. It utilizes surplus milk in the flush season. It utilizes abundant milk production in certain localized area. It makes use of surplus milk below excellent grade. By either concentrating or drying less space is needed to store and it becomes less bulky and therefore it can be transported to any part of the world. The keeping quality of milk is increased. The concentrated products give considerable saving in the cost of packaging, storage and transportation. Milk concentrates can be easily reconstituted with required amount of water corresponding to that removed by evaporation to yield a product having normal consistency of milk. It is estimated that nearly two per cent of the world’s milk production is converted into different types of condensed or concentrated milks.

Brief history and developments: The present day concept of preservation of milk by concentration and by application of heat had the beginning with the pioneering work of French man Nicholas Appert around 1793. Gail Bordon of USA was first to commercially exploit the method of concentration of milk under vacuum. He was awarded U.S. Patent in the year 1856 for processing milk in a semi-fluid state after evaporating under vacuum. Commercial production of sweetened condensed milk by Gail Bordon started in 1856.

The method of preserving various food stuffs by drying them, and thereby depriving microorganisms of the water necessary for their growth, has been known for centuries. According to Marco Polo’s accounts of his travel in Asia in 13^th century, soldiers of Kublai Khan carried dried milk on excursions. Before it was used, water was added to a portion of dried material. Mixing was accomplished by movement of the horse during riding on the trip. The recombined product was then consumed at the mealtime. The belief is that part of the fat was removed from the milk before drying and dehydration was accomplished by solar heating.

Drying is defined as the removal of the liquid, usually water, from a product by evaporation, leaving the solids in an essentially dry state. Today the production of dried milk and milk products has become important segment of dairy industry. Dry milk provides a means of preserving the excess milk supply during the flush season for use during the lean season. The value added dried dairy products like malted milk foods, infant food and infant formulae and dairy whiteners are convenient ready to use products having wide acceptance. The water content of milk powder ranges between 2.5 and 5%, and no microbial growth occurs at such low water content. Drying extends the shelf life of milk, simultaneously reducing its weight and volume. The main purpose of drying milk are: a) to improve the storage life of the product due to low moisture content, b) to reduce cost for storage and transportation of product due to reduced bulk, and c) to provide convenient product for utilization in many dairy and food preparations.

The production of dried milks to a great extent is now being governed by the market requirement and to some specialized use of such products. Considerable quantities of dried skim milk powders are being used extensively in the preparation of ‘Reconstituted and Recombined milks”. Milk powders are also used extensively in the manufacture of ice cream, bakery products, confectionary products, cottage cheese and in other cheese varieties. The greatest proportion of milk powder is utilized in confectioneries, such as milk chocolate, caramels, soft sweets, coatings, biscuits and cakes. In these products, milk powder has a special effect on the quality of particular products: it improves consistency, flavour as well as nutritional value and shelf life.

Ice cream over the years has come to acquire an easy acceptance as a healthy, nutritious and hygienic food for the aged, sick, growing children and adults. Its popularity, as demonstrated on all types of occasions is growing fast and its potential appears to be unlimited.

Gone are the days when the word “Ice Cream” was synonymous with strawberry and vanilla flavours or the innocuous orange. Ice cream is available in many forms, flavours and packages. Today, there are exotic variations to titilate the palate, such as Jingle Bells, Goody goody Gum Drops, Champagne Snowballs, Mr. Frost, Tutty Fruity, Butter Scotch, etc, waiting to launch customers on a gastronomical voyage.

It is uncertain how long ice cream has been produced, however, the International Association of Ice cream Manufacturers (1966) traces the beginnings of ice cream and frozen desserts to iced drinks enjoyed by Alexander the Great in the fourth century B.C. down through the years Nero in the first century A. D., Marco Polo in the 13^th century through Italy and France to England in 1643-1649, and to America around 1700. From a very old writings it has been learnt that the Chinese liked a frozen product made by mixing fruit juices with snow, what we now call water ice. It is believed that ice cream evolved from iced beverages and water ices that were popular in the medieval period. This technique later spread to ancient Greece and Rome, where the wealthy, were partial to frozen desserts.

After disappearing for several centuries, ice creams in various forms reappeared in Italy in the Middle Ages, most probably as a result of Marco Polo returning to Italy in 1295 after a 16-17 year stay in China, where he had learnt to appreciate a frozen dessert based on milk. There is no gainsaying the fact that the true origin of ice cream cannot be proclaimed with a fair measure of certainty but, all the same, the Italians claim that Benaroo Bountalenti, a resident of Tuscany, invented ice cream in the early 1300s. From Italy ice cream spread over Europe during the 17^th century, and for long remained a luxury product for the royal courts. Italian ice cream was very popular in London around 1870.

Dairy byproducts constitute an important segment of dairy industry. An important criterion in the economic choice of any process is the efficient utilization of byproduct that is produced along with the main product. The main byproducts of dairy industry are skim milk, buttermilk, whey and ghee residue. Each and every component of milk must be judiciously processed into edible form not only to improve the profitability of dairy industry but also to make best use of the unique nutritional value of the precious milk constituents on one hand, and to prevent environmental pollution, on the other. However, dairy plants, particularly in India, are usually confronted with the problem of byproduct utilization, especially that of whey and ghee residue in economical manner.

Skim milk is a byproduct obtained during the manufacture of cream. It is rich in solids-not-fat content and has high nutritional value. In dairy plants, it is mostly utilized either in standardization for the manufacture of main dairy products or preserved by removing moisture in milk powder form. The skim milk when utilized in either of these two forms or consumed as liquid, is not considered a byproduct. It is regarded as a byproduct only when it is either not economically utilized or utilized for derived byproducts, like casein and other related products, co-precipitates, protein hydrolyzates, etc.

Buttermilk is the byproduct obtained during butter manufacture. Sweet cream buttermilk resembles skim milk in gross chemical composition and is usually admixed with bulk of skim milk for further spray drying or even product manufacture in dairy plants. Desi buttermilk, on the other hand, has long been an important domestic beverage in India. It has high nutritive and therapeutic value. It also finds its way in the preparation of a host of culinary dishes such as kadhi, dhokla and idili. Also a number of federations and private plants sell salted and spiced buttermilk in 200 ml pouches.

Introduction

In terms of individual health and physical condition, the situation in modern society is rather giving rise to concern. The last decades have seen a tremendous increase in availability and variety of food products which has undoubtedly affected the food habits of the average individual. Despite the fact that food has become overall safer and increased accessibility allows for healthier diets, worrying we are nevertheless faced nowadays with diet- related diseases of proper epidemic proportions. We now encounter an epidemic of obesity that spreads not only to the majority of the adult population but also, more worryingly, to young people who have rarely the option of alternative diets. Moreover, as scientific proofs for the link between diet and disease (particularly cardiovascular diseases and some cancers) accumulate, action is urgently needed. There are an increasing number of calls for action. It is within this situation that functional foods have developed. They assume a highly targeted solution to the diet related diseases with effective reduction of risk and improved physical and mental well being. That represents a big step from the traditional food-for-nutrition but the scientific milieu is ready to take the chances. The emerging ‘functional food science’ is focusing research on the effects of functional foods on growth, development, metabolism, the cardiovascular system, intestinal physiology, and even on behavioural and psychological functions (FAIR, 2000, Vol. 1). In view of these facts, it should appear necessary to assess and evaluate the developments in food production in terms of their effect on the individual consumer and the society at large.

There is no single factor as important in the production of fine quality dairy products as absolute and complete cleanliness.

R.B. Barrett

It is not enough to provide milk for man, it must be high quality milk. It would be impossible to provide man with milk and milk products of superior quality if we were unable to remove milk soil and to kill residual microorganisms. Respectively, these are the processes of cleaning and sanitizing.

To successfully provide the atmosphere for proper food safety, the basics must be thoroughly understood. The basics of food safety begin with good understanding of sanitation processes, food-handling procedures that protect from, or eliminate cross contamination problems and specific attention to inspection of and follow up for all processes. Food safety activities need to be programmed into available time of day scheduling just as production requirements do. Whether special personnel or separate shifts handle cleaning responsibilities or you clean as you go on the production line, time must be made available. Safe products leaving the facility must be the watch word of all employees involved with the process.

In order to ensure safe food supply a high level of sanitation should be maintained throughout the food production chain. The word ‘sanitation’ is derived from the Latin word “sanitas” which means “health”. To further apply this word to the food industry, sanitation is the creation and maintenance of hygienic and healthful conditions when processing, preparing and handling food. Sanitation is the application of science to provide wholesome food handled in a hygienic environment by healthy food handlers to prevent contamination by food spoilage microorganisms. Effective sanitation refers to the mechanisms, which accomplish these goals.

We all are familiar with the word “quality”. If we bring some fruits or vegetables from the market, the other family members will reflect on their quality by making observations such as: fresh or stale, good or bad quality or inferior product, etc. These observations are perceptions of consumers based on the sensory attributes of the fruit or vegetable colour, appearance, touch, smell or taste.

The quality characteristics of food that are acceptable to consumers are comprehended under the term “Food Quality. It includes external factors such as appearance (size, shape, colour, gloss, and consistency); internal factors (chemical, physical, microbiological) and characteristics/ specifications prescribed under the Government laws/standards. If consumer’s perceptions regarding quality of food are not positive he or she either will not purchase the material or will be paying less compared to when the consumer has positive perception about the quality.

The relationship between quality, profitability and market share has been well established. In the quest of quality, the dairy business is passing through revolutionary changes and the need for such changes has been very well realized. The leaders have initiated the process of setting vision and are working hard to provide the basic infrastructure with necessary resources. This has become a point of vital importance as the nation has now captured the first rank in milk production globally and is now ready and set to march ahead in the global race for dairy products market. Our country has great potential to export the dairy products such as cheese particularly Mozzarella, Feta, and indigenous products such as ghee, khoa, chhana, paneer, and array of sweets. Food items or dairy products to be traded in the international markets should be manufactured in accordance with global accepted norms and standards. In order to improve the quality of milk and milk products the Government of India is focusing on “Clean Milk Production”. As a dairy technologists and entrepreneurs, we must ensure production of quality products.

    1.    Rice is a
        a)    Edible fruit    b)    Edible Vegetable
        c)    Edible flower    d)    All
    2.    Major components in cereal seeds are 
        a)    Endosperm    b)    Germ or embryo
        c)    a & b    d)    None
    3.    Bran is composed of 
        a)    Pericarp    b)    Testa
        c)    aleuron layer    d)    All
    4.    Oats contains ______________ percent of hull
        a)    50    b)    40
        c)    30    d)    20

    1.    Asepsis is a process of 
        a)    Removal of microorganisms    
        b)    Keeping out microorganisms
        c)    Hindering the growth & activity of microorganisms    
        d)    Killing the microorganisms
    2.    Self-decomposition of the food is prevented by
        a)    Inactivation of enzymes    b)    Delay of chemical reactions
        c)    a & b    d)    None
    3.    Commercially available fruit beverages are generally pasteurized at 
        a)    85°C for 25 to  30 min    b)    62.5°C for 25 to  30 min
        c)    71.1°C for 15 to  30 sec    d)    92.1°C for 15 to  30 min

    1.    As per FSSAI, 2011 regulations, what is the fat and SNF content in buffalo milk
        a)    5 & 9    b)    6 & 8
        c)    6 & 9    d)    None
    2.    As per FSSAI, 2011 regulations, what is the fat and SNF content in  cow milk
        a)    4 & 9    b)    4 & 8.5
        c)    6 & 9    d)    None
    3.    As per FSSAI, 2011 regulations, what is the fat and SNF content in  standardized milk
        a)    4 & 9    b)    4.5 & 8.5
        c)    6 & 9    d)    None

    1.    Fortification of common salt is done with 
        a)    Potassium iodide    b)    Potassium iodate
        c)    Both a & b    d)    None
    2.    Vinegar is a 
        a)    Class-I preservative    b)    Class-II preservative
        c)    Natural preservative    d)    a & c
    3.    As per FSSAI regulations, the permitted level of Sulphur dioxide in RTS beverages is not more than ______ ppm
        a)    100    b)    70
        c)    150    d)    80
    4.    Sodium nitrite is a
        a)    Preservative    b)    Buffering agent
        c)    Curing agent    d)    Flavour enhancer

    1.    Life blood of food companies are
        a)    Existing products    b)    New Products
        c)     New packaging material    d)     Food technologists
    2.    New Products are developed to meet
        a)    Health & Nutritional requirements
        b)    Environmental & Social requirements
        c)     Convenience & handling
        d)     All
    3.    What are the characteristics of a line extension in a variant of an established line of food products 
        a)    Little research    
        b)    Minimum manufacturing changes
        c)     No change in logistics and supply chain
        d)     All
    4.    The following one is not a characteristic of new product development through line extension
        a)    New purchasing skills
        b)    No change in logistics and supply chain
        c)     No change in storage of RM &PM
        d)     Minimum R&D

    1.    Laminar flow hood works on the principle of 
        a)    High-efficiency particulate air filter
        b)    High-energy particulate air filter
        c)     High-efficiency pressure air filter
        d)     None
    2.    Most of the organisms are killed
        a)    121°C for 5 min.    b)    15lb/in²
        c)     a & b    d)     None
    3.    Autoclaving is not recommended for
        a)    Oils    b)    Powders
        c)     Sensitive fluids    d)     All

    1.    What is the percentage of water in an adult’s body weight
        a)    50%    b)    60%
        c)    90%    d)    70%
    2.    __________ is a direct reactant in hydrolytic processes of many foods
        a)    Water    b)    Moisture content
        c)    Both a&b    d)    None
    3.    The bond angle of the isolated water molecule (vapor state) is
        a)    109°    b)    104.5°
        c)    109°28'    d)     103.6°

Definition
Production and operations management is the process of conversion of inputs into outputs, using physical resources, so as to provide the desired utility/utilities —of form, place, possession or state or a combination thereof—to the customer while meeting the other organizational objectives of effectiveness, efficiency and adaptability. It distinguishes itself from the other functions such as personnel, marketing etc. by its primary concern for ‘conversion by using physical resources’. Figure 1.1 describes a generalized concept of production system. It takes resource inputs and processes them to produce useful outputs in the form of goods or services.

SOURCES OF LOSSES
In most of the cases of excessive fat or product loss, a combination of several factors rather than any single factor are responsible.
 
Inaccuracy in weighing: Receiving room scales should be checked regularly with a set of weights. The check should be made immediately before weighing operations begin. Improper drainage of the weighbowl will permit a carry over into the next batch dumped, resulting in incorrect weighing. Errors in weight in bulk handling methods may be caused also by improper leveling of the tank, incorrect calibration of the measuring rod, or carelessness on the part of the person taking the measurement.
 
Inaccuracy in sampling: Failure to collect representative samples may sometime cause sizeable losses. Milk should be properly agitated before taking samples. The composite sample should be preserved and refrigerated and should be protected from mould growth.

In economics and business, specifically cost accounting, the break-even-point (BEP) is the point at which cost or expenses and revenue are equal: there is no net loss or gain, and one has “broken even”. A profit or a loss has not been made, although opportunity costs have been paid, and capital has received the risk-adjusted, expected return.
For example, if a business sells less than 1000 liters of milk each day, it will make a loss, if it sells more, it will be a profit. With this information, the business managers will then need to see if they expect to be able to process and sell 1000 liters of milk per day.

Traditionally, Labour Laws have a protective function consisting of established standards both to protect workers in their workplace and to provide them a basic minimum level of living conditions. Alongwith this function, there also existed in most systems, a legal framework for the regulation of industrial relations between employers and workers. These functions had their impact on problems of development. The emphasis was more on labour legislation for its own sake, development being a separate proposition. This mutual lack of concern was perhaps due to historical factors. The most important aspect is the fact that in developed countries of the Western world, labour legislation followed the emergence of industrialization and in response to a demand for economic and social betterment of the workers, whereas in developing countries the emergence of labour laws preceded industrial growth.

Importance and Value of Human Resources

The employees are the human resources of an organization which are crucial for its functioning. The acquisition of human resources and their maintenance involves costs. Manpower costs include costs of research and designing of manpower programmes that is man-power planning, work study and designing of personnel policies etc. The costs of commissioning of man power, that is, costs of recruitment, induction, placement and training etc. The cost of maintenance of these resources is a very significant component of the total costs of an organization. Maintenance costs include wages and salaries, welfare and medical benefits, PF, gratuity and other retiring benefits etc. These costs form a substantial part of the total costs of an organization. In the last 30 years the treatment of manpower costs has been recognized as a separate division in accounting practices. The other assets like machinery, buildings etc come under depreciation. In contrast, human assets are the employees at all levels, as they grow in age and experience, add to their productivity and capacity to earn for the organization and become more valuable.

RECRUITMENT 
Recruitment is the process of identifying the prospective employees, stimulating and encouraging them to apply for a particular job or jobs in an organization. It is a positive action as it involves inviting people to apply. The purpose is to have an inventory of eligible persons from amongst whom proper selection of the most suitable person can be made.

The Process of Recruitment
Before thinking of inviting people to apply for a job one has to decide what types of persons are to be invited and what their characteristics should be. This calls for fixing the ‘job specifications’ which may also be called ‘man specifications’. Job specifications are based on job description which is dependent upon the nature and requirements of a job. 

Thus, job specification will be different for each job. The various elements of job specification are:

Training is a major manpower management function. No organization can afford not to train its employees, regardless of his previous education, training, and experience. He has to be introduced into the work environment of his new employer inducted and taught to perform his assigned tasks in a new milieu. Moreover, changing technology, increasing automation in offices and factories and in almost all institutions is bringing about redesigned or altered jobs. People are constantly being “trained” and retrained by the way their superiors and other employees associate them with work. 
Training is a part of management development and also a form of organizational development. The most effective managers are those who can best develop the human resources of an organization for the purpose of achieving organizational goals and objectives. If the employees perceive training as a means to achieve their personal goals at work, they will welcome such opportunities. Some essentials about training may be borne in mind and they are:

What is Performance Appraisal?

Performance Appraisal (PA) is the process through which an individual employee’s behaviour and accomplishments for a fixed time period are measured and evaluated. The major purpose of measuring and evaluating is to assess the worth or value of an employee. Performance appraisal is a systematic and objective way of judging the relative worth or ability of an employee in performing his task. Performance appraisal helps to identify those who are performing their assigned tasks well and those who are not and the reasons for such performance.

Whatever may be the nature and strength of resistance to the performance appraisal, management cannot relinquish this practice. Without employee appraisal, salary increases, reassignments or promotions cannot be administered rationally. Each of these areas has its specific problems and one of the solutions of modern times has been offered by an unusually promising frame work offered by Peter Drucker concept of Management by Objectives (MBO).
MBO calls on the subordinate to set his short-term performance goals in consultation with his superior. Goals explicitly state the actions which the employee will follow. Instead of being appraised in a traditional way by his superior, the subordinate appraises his own performance by evaluating it vis-à-vis the goals. Before establishing a goal, the individual studies his job, assesses his potentialities, and formulates some specific plans to reach the goal. The supervisor is not the evaluator, but directs the goal-setting process to ensure that it matches the objectives of the organization.

TRANSFER

A transfer is a change in job assignment. It may involve a promotion or demotion or no change at all in responsibility and status. It is a change in assignment in which the employee moves to another job at approximately the same level of responsibility, the same skill, the level of pay. Transfer is to be distinguished from promotion and demotion which imply an ascending or descending change respectively, in the hierarchy of positions. A transfer may be either temporary or permanent, depending upon the need, and may occur within a department, between departments and divisions, or between plants or officers within a company/organization.

Employee motivation and job enrichment are described as two management techniques used to improve human behaviour and attitude towards work, with a view to utilize available human resources more efficiently and thus make man-management more effective. Just as the employee has certain wants that the organization is expected to satisfy, the organization too expects certain types of behaviour usually termed as ‘Direction’ or ‘Motivation’. Obviously this managerial function is not so easy, as it involves many problems, and it is these problems and their possible solutions that one is concerned.
Job enrichment is also a motivational problem created by the alienation of employees from their work, or by lack of their interest in their work. Here the problem is how to make the work more interesting, purposeful and acceptable to employees so that they may perform it more enthusiastically and with a greater sense of responsibility. Like motivation this is also a problem of human behaviour and work attitude. In fact both employee motivation and job enrichment are the problems which every supervisor and manager has to face while working and making their subordinates work.

Apart from the job content and specialization, the conditions or the atmosphere in which employees work is critical to their productivity. Work environment includes the tools and equipment provided to perform the job, the atmosphere at the work place, worker motivation etc.

Tools and Equipments

The quality of tools and equipment provided to a worker has a profound effect on the worker’s contribution to his job. A poorly designed tool can cause excessive physical burden on the worker and may result in fatigue. A faulty computer monitor can cause severe eyestrain, which might affect productivity in an office environment. Hence, tools and equipment should be appropriate for the production task. The design should consider ergonomic factors like grasping pressure, size, weight, ease of use etc. when designed properly, tools enable users to work efficiently, resulting in higher productivity. The equipment installed should be able to meet the capacity requirements of the job, have safety features and be easy to use. The use of the right tools and equipment can improve productivity in an organization substantially.

There are specific hazards associated with equipment, operation or a particular section. Such possible hazards and their preventive measures are discussed below.
I. Milk Reception Dock
    1.    Where the top of a vat, into which a 40 litre can of milk is to be dumped, is higher than the milk can, two men should lift and empty the can.
    2.    Where steam jet method of can washing is used, to avoid burning, employees would be furnished with protective equipment, including rubber boots and long aprons
    3.    Cans should be stacked in areas away from frequently used passage ways
    4.    Cans should not be stacked so high that they may fall and injure someone

Since time immemorial when man used primitive tools and machines to carry his loads, to draw his water, to till his land and to fabricate his building materials, he has been faced with the prospect of maintaining these assets until such time as he considered their useful life to be ended. Maintenance is very important to extend the useful life of an asset. Maintenance is usually viewed only as a repair function. It is, however, “a combination of any actions carried out to retain an item in, or restore it to, an acceptance condition”. In fact maintenance keeps or ensures that the entire production system is kept reliable, productive and efficient. All departments of a production system may have been designed beautifully without giving due consideration to maintenance management. The end result is obvious. Organizations like the National Productivity Council and others are playing a vital role in propagating the importance of Maintenance Management of all assets of the organization. In fact, all organizations must be having some assets, and hence the need for proper maintenance and ‘physical assets management’ which is synonymous with the word ‘Tero-technology’.

Concept of Inventory

‘Inventory’ may be defined as ‘usable but idle resource’. If resource is some physical and tangible object such as materials, then it is generally termed as stock. Thus stock or inventory are synonymous terms though inventory has wider implications. Broadly speaking, the problem of inventory management is one of maintaining, for a given financial investment, an adequate supply of something to meet an expected demand pattern. This could be raw materials work in progress finished products or the spares and other indirect materials. Inventory can be one of the indicators of the management effectiveness on the materials management front. Inventory turnover ratio (annual demand/average inventory) is an index of business performance. A soundly managed organization will have higher inventory turnover ratio and vice-versa. Inventory management deals with the determination of optimal policies and procedures for procurement of commodities. Since it is quite difficult to imagine a real work situation in which the required material will be made available at the point of use instantaneously, hence maintaining, inventories becomes almost necessary. Thus inventories could be visualized as ‘necessary evil’.

A broader definition of a tool is an entity used to interface between two or more domains that facilitates more effective action of one domain upon the other. The most basic tools are simple machines. For example, a crowbar simply functions as a lever. The further out from the pivot point, the more force is transmitted along the lever. A hammer typically interfaces between the operator’s hand and the nail the operator wishes to strike.
A telephone is a communication tool that interfaces between two people engaged in conversation at one level. And between each user and the communication network at another. It is in the domain of media and communications technology that a counterintuitive aspect of our relationships with our tools first began to gain popular recognition.
Marshall McLuhan famously said “We shape our tools. And then our tools shape us.” McLuhan was referring to the fact that our social practices co-evolve with our use of new tools and the refinements we make to existing tools.

The machine parts, which have relative motion, rub against each other. The rubbing surfaces are never perfectly smooth, even when they are highly polished. If they are observed under a microscope, one sees small depressions and elevations which get interlocked when the machine parts are under pressure, and give rise to a resisting force called frictional force. Due to friction, the parts get worn out and become useless. Friction produces heat, which, in this case, represents loss of work. To reduce this wear and loss of power caused by friction, certain foreign substances are introduced between the rubbing surfaces which keep them apart. These substances are called lubricants; and lubrication is the science of reducing friction by the application of a suitable substance between the rubbing surfaces of bodies having relative motion.

Dairy industry has long dealt with issues of food pathogens and inadvertent adulteration; it is time to review the plant systems with a new perspective. Each plant has its own handling protocols, physical lay-out and employee policies. Milk and other materials entering the facilities, till the distribution of the finished product needs special attention.
 
I. INCOMING MATERIALS

In general, start by considering the milk, food ingredients, packaging, chemicals and other materials that come into plant facility and warehouses, and ensure that these product streams are secure, and that materials are stored in asecure place.

The primary objective of dairy plant hygiene is to ensure the consistent daily turn-out of safe and clean products which comply with pure-food and public health laws. A secondary and commercially important aim is to preserve the keeping quality of dairy products and so enhance consumer confidence in them. An integral part of a dairy is the quality control laboratory. Continuous testing is necessary for many purposes, including equipment hygiene. Bacteriological standards of dairy products can be maintained only if the raw product is of good bacteriological quality and is protected against contamination from the equipment with which it comes in contact during all stages of processing. 
Many factors may influence the maintenance of dairy equipment in a hygienic condition; the most important are the dairy buildings, the materials and construction of the equipment, personnel, water supply, cleaning procedures, and laboratory control. It is quite impossible to place these points in order of importance, efficient control of dairy plant hygiene being dependent on proper attention to all factors.

Food Hygiene is a scientific discipline describing handling, preparation, and storage of food in ways that prevent foodborne illness. This includes a number of routines that should be followed to avoid potentially severe health hazards. Food can transmit disease from person to person as well as serve as a growth medium for bacteria that can cause food poisoning. Since food hygiene has a direct effect on the health of individuals patronizing the catering facility, it is obligatory on the part of the management to lay down definite guidelines for maintaining hygienic conditions and ensuring their proper implementation. Cleanliness should be the basis of all food hygiene programmes and should be aimed at food protection as well as improving and maintaining the quality of food. 

The compliance with hygienic and aesthetic standards in the dairy factory is, in the final analysis, dependent on the human element. Each employee, from top management to the most junior operative, has his role in the factory sanitation programme and carelessness at any stage may cause quality deterioration of products or endanger the health of consumers. Legal action against the dairy may also result from neglect of hygiene. Personnel hygiene refers to the personal cleanliness and related habits of the workers. Milkborne infections frequently originate from food contaminated by workers through their hands, breath, hair, perspiration, pimples, infected wounds, coughs, and sneezes. Transfer of even traces of human and animal excreta by the workers is a potential source of pathogenic microorganisms. Foodborne illness is known to originate from workers who were ill and practiced unsanitary food handling methods or poor personal hygiene. Even the healthy worker, who does not exhibit the symptoms of the disease, may harbour food poisoning bacteria in the respiratory or intestinal tract. It is always desirable, as a matter of practice, to look at different parts of the human body in terms of potential sources of bacterial contamination. Provisions regarding personal hygiene of employees are contained in all legislation dealing with milk treatment.

Water Requirements

Dairy plant requires large quantities of water on a daily basis for processing and cleaning purposes. Normally the specific water consumption ranges from 1000-5000 litres per 1000 litres of milk processed. The actual requirement can vary between dairies and is a function of 
    a)    Manufacturing process or manufacturing profile.
    b)    Auxiliary processes such as steam generation, design of the refrigeration processes and extent of social services.
    c)    Multiple use/reuse.
Water is a very valuable basic natural resource  and needs careful consumption. The water supply system in a dairy plant should be designed in such a way that consumption for each manufacturing department and auxiliary processes can be determined. This makes it possible to influence water consumption directly, and major losses can be determined very rapidly.

Cleaning and sanitizing of dairy plants is essential for providing safe milk products to the consumers as well as for ensuring the good shelf life of these products. It ensures cleanliness, hygiene of the equipments and surroundings and also ensures that the products meet the safety standards. Cleaning of dairy plant consists of broadly of removing the soil from the surface of the equipment by dissolving or suspending the soil in a warm solution of suitable cleaning agents. In the dairy industry, the soil is primarily milk and milk product residues which may be more or less modified by processing treatment. 
Milk and milk product residues are complex mixtures of milk sugar, fat, proteins and mineral salts. Some of these solids are present in emulsion, some are in a colloidal state, and others are in true solution. When milk products are heated in vats or pumped through sanitary pipe lines or over coolers, the metal or glass surfaces become coated with milk remains, which, if allowed to dry, may be difficult to remove.

Milk processing plants involve processing of raw milk into products like market milk, cheese, butter, ice cream, condensed milk, dried milks and traditional dairy products. The by-products processing includes buttermilk, whey and its derivatives. Dairy effluents contain dissolved sugar, protein, fat and minerals. Spills and leaks of products or by-products, residual milk or milk products in piping and equipment before cleaning, wash solutions from equipment and floors, condensate from evaporation processes and cheese trimmings are some of the sources of dairy effluents in a dairy plant. The key parameters are the biological oxygen demand (BOD), chemical oxygen demand (COD), total suspended solids, total dissolved solids etc. Common dairy waste techniques include grease traps, oil water separators for separation of floatable solids, equalization tanks. Biological treatment consists of aerobic and anaerobic process.