eChapters

9.1 Introduction

Depleting natural resources, regulations on synthetic material, growing environmental awareness and economic considerations today happens to be major driving force for utilization of wastes from the agricultural crops and their residues throughout world [1]. These challenges have led to the introduction of sustainable waste management practices via optimization of processing technologies for minimization and creative conversion of the plant and the processing industries biowastes the world over [2,3,4,5]. Although world prices for sugar and petroleum products have shown spectacular variations during the last few decades, the long term outlook is very likely to be a continuous increase in the price of all fossil fuels and stagnation, at best, for the price of sugar [6]. This gloomy prospect led to the renewed interest in the wastes of the sugarcane industry during the last 50 years and has proved that the optimal use of wastes can provide not only a non-negligible support to the sugarcane industry but will also be able to redress the difficult situation sugar is presently experiencing [7]. Reliable statistics are not available to show the detailed end uses of these wastes on a world basis, but from a very rough picture of their trade, we can say that the wastes from the sugar and jaggery industry serve to be amongst the richest bioresource in this era of recycling of biowastes for renewable wealth generation [8].

8.1 Introduction

Spices are appetizers and hence, esse ntially used in the culinary preparations. They also possess antioxidant, antimicrobial and antibiotic properties. Further, they possess medicinal properties and hence, play an important role in human health.

According to International Organization for Standards (ISO), there is no clear cut division between ‘Spices’ & ‘Condiments’ and as such they have been clubbed together. The term ‘Spices’ & ‘condiments’ applies to “such natural plants or vegetable products or mixtures there of, in whole or ground form, which are used for imparting flavour, aroma and piquancy and seasoning of foods”. Spices are divided into different groups based on their plant components such as floral, fruits, berries, seeds, rhizomes, roots, leaves, kernel, aril, bark, bulbs etc.

About 70 spices are grown in different parts of the world and a major portion of these are grown in India. Hence, India is called “The home of Spices”. It is well known that spices played a significant role in ancient times, in the development of civilization – the life of the people and trade among the nations of East and West. Spices like ginger, pepper and turmeric have an intense and immediate impact on sensory perceptions and exhibit strong physiological effects as food and medicinal constituents. Some spices and herbs like cardamom, saffron and vanilla, which have less intense but more delicate sensory effects, are well known for their contribution to fragrance and usage as food flavouring agents. The history of spices and their use in food and medicine in ancient India have been reviewed earlier [1-3].

7.1 Introduction

Fisheries are emerging as one of the fastest growing food production system all-over the world. The potential for fisheries development world over and especially in India is highly promising in view of physical and biological resources available coupled with technological development. The demand for fish fishery products is ever increasing as the awareness of health benefits are being made available to public at large. The world fish production has not kept pace with demand which means less and less fish is available. Nevertheless, a large fraction of this valuable commodity is wasted due to deterioration after landing or consumer preference. An estimate by FAO [1] indicates nearly 20-25% of the total catches are wasted as postharvest loss. Better utilization of aquatic resources should therefore, aim primarily at reducing this enormous loss by improving preservation of fish and fishery products and upgrading the discarded low value fish to high value fishery products. The processing of fish into different types of products generates considerable waste. Commercially, fish is being processed into fillets, steaks, mince, canned products and a variety of ready-to-eat products. Fish processing plants contributes substantial wastes in the form of skins, bones, offal, exoskeletons from shrimps and nutrients in wash water from surimi plants.

Fish processing waste utilization is an important issue for the seafood industry both from a regulatory standpoint as well as one that has potential economic impacts. It is estimated that only 25-50% of the raw material is utilized for primary products (fillets, canned and stabilized mince production). The remaining 50-75% of the raw material is considered processing waste and is utilized for low-value products or disposed-off at sea. A large volume of solid waste is currently processed into fish meal, fish protein hydrolysates, and fertilizers. A small percentage is processed into higher valued items, such as, seafood flavourants, colourants, chitosan, enzymes, etc.

6.1 Introduction

The food industry produces large volumes of waste both solid and liquid, starting from the initial step of raw material to the final consumption of processed food. Apart from a loss of valuable biomass and nutrients, the generated waste poses increased disposal and potentially severe pollution problems. Meat and meat industry is no exception where slaughter houses, meat processors, wholesalers and rendering plant generates huge amount of waste [1, 2].

Meat and meat processing industry, is among the least profitable industries despite its immense size and large gross sales. Effective recovery and utilization of by-products and wastes is the lifeline of meat and poultry processing industry. Thus, it becomes imperative that an effort be made to reduce expenses by employing the use of new or modified processing methods and through in-plant treatment, where waste effluents and by-products could be recovered and often upgraded to useful products of higher value. Meat processing wastes have a potential for recycling raw materials or for conversion into useful products of higher value as by-product or even as raw material for other industries or for use as food or feed after biological treatment.

5.1 Introduction

Waste from the dairy processing industry is generated through production of milk products at different stages. With diversification of dairy products, by-products have also gained some importance. Utilization of dairy by- products improves economical and nutritional aspects of milk production and reduces environmental pollution originating from dairy waste. Important dairy by-products include butter milk, ghee residues and whey, the major waste arising from production of cheese, casein, paneer and chhana. Whey arises as a result of protein coagulation/precipitation in the preparation of these products. It is used for manufacture of whey powder, whey drinks and lactose (milk sugar). Whey protein concentrates can be prepared by modern technological methods like ultra-filtration and reverse osmosis. Desi buttermilk is an important domestic beverage since olden days. Ghee residue can be utilized for manufacture of chocolate burfi, samosa filling etc. Hence, utilization of dairy waste particularly whey, butter milk and ghee residues obtained during manufacturing of various main products, has not only increased the availability of nutritional milk foods but has also indicated the profitable method of by products utilization and helped in minimizing the problems of pollution. This chapter focuses on utilization of these dairy industry wastes.

4.1 Introduction

A huge amount of waste in the form of liquid and solid is produced in the fruit and vegetable processing industry which causes pollution problem if not utilized or disposed off properly. Generally solid waste is dumped in local landfills, eaten and scattered by stray animals, which has now become a major cause of environmental pollution. The waste obtained from fruit processing industry is extremely diverse due to the use of wide variety of fruits and vegetables, the broad range of processes and the multiplicity of the product [79]. The solid waste from fruits and vegetables includes peel, stone, rag, seed, core etc is of economic value and can be used for manufacturing of various by-products [21]. The extent of the waste produced from processing industries of some of the important fruits and vegetables, is given in Table 1.

In India, utilization of fruits and vegetables for processing is hardly 1.8% of the total production. There were 5166 processing units till 1^st Jan, 2009 of fruits and vegetables products throughout the country. About 90% of these units are small scale units with annual production limit of 50-250 tonnes. These units have no organized methods of waste disposal. In certain places this waste is taken away by farmers for their disposal as cattle feed or field manure.

1.1 Introduction

Due to the ever increasing world population, the demand for food would also increase. India is one of the largest food producer countries of the world (first in milk production, second largest in fruit and vegetable production and third largest in grains production). It is the seventh-largest country in the world, with a total land area of 3,287,263 square kilometres. India has varied climates of snow covered Himalayas, desserts, oceans, fertile plains and areas receiving the highest rainfall in the world. Name any food item; it can be grown in one or the other part of the country. All these make the production of various types of foods of plant (fruits, vegetables, cereals, pulses, oilseeds, spices etc) as well as animal origin (fish, meat, milk etc.) possible in the country. The annual production of cereals, fruits and vegetables is 260, 57 and 77 million tonnes respectively, besides this, the production of cow and buffalo milk is about 102.1 million tonnes and that of sugarcane and spices are 355.52 and 1.1 million tonnes respectively [15]. Table 1 shows that the production of various food items has increased many folds during the last five decades. On one hand, we feel proud as we produce one of the largest quantities of foods in the world and there has been an enormous rise in the production of various foods in India during the last five decades, on the other hand we should be very much worried being a leading country as far as the wastage of food in the world is concerned. The postharvest losses are huge and only meagre quantity (2%) of the food is processed. Sharma [41] very rightly said that when we do not agree to throw away Rs 4000/-per month out of a salary of Rs 10,000/-per month then why do we accept 40% postproduction losses of food in the country. This would require immediate necessary action to save a major portion of the food that has already been produced.

3.1 Introduction

The production of food grains in India is around 200 million tonnes and most of the grains are converted to primary products after primary processing such as threshing, dehulling, de-branning. Some of the grains are converted to secondary products such as flour or grits. The yields of primary and secondary products range between 65-80% indicating a wastage of 20-35%. These wastes lead to unclean surroundings and air pollution due to fine dust. Hence, proper waste management/utilization of food grain processing industries has become a societal need for a clean environment.

The term ‘waste’ has different meanings to different people. It can be retractions from the main process or less utilizable by-products or undesirable waste material depending on the commodity. All food-processing industries generate wastes and create problems for its management. The best way the food processing industry can treat its waste is to avoid producing it. Much of the waste now being produced or generated in some food processing plants can become a managed resource for producing economic credits. In fact, waste utilization is one of the world’s prominent industries and its activities cut across the normal divisions into which industries are placed. Similarly, there will be wastes from agriculture, animal and meat industries, textile, rubber etc. Even the local governmental activities that collect and dispose the household wastes become apparent in terms of the huge size of it.

2.1 Introduction

Each step in the food industry system e.g. food production, processing, transportation, storage, distribution and marketing, has some impact on the environment and there is much concern about environmental pollution. Due to the highly diversified nature of the food industry, various food processing, handling and packaging operations create wastes of different quality and quantity, which, if not treated, could lead to increasing disposal problems and severe pollution problems [24]. The preservation of the natural environment from industrial pollution is currently receiving much attention. In food industry, the most important problem is treatment and disposal of large quantities of waste water, a by-product of various processing operations. It is one of the largest industry groups comprising the manufacturing sector of the U.S. economy [47]. Likewise, India is the world’s second largest producer of food next to China, and has the potential of being the largest food processor. The total food production in India is likely to double in the next ten years [22]. Flour and grain; soft drinks and carbonated water; breweries; starch and miscellaneous food products; meat, poultry and fish; tea, coffee and other beverages; fruit juices; animal feed; sugar; distilleries and blending of spirits; cocoa, chocolates and sugar confectioneries; agricultural and food chemicals and industrial packaging are important sub-sectors of the food processing industry. Food processing projects involve the processing and packaging of meat products, fish and shell fish, dairy products, fruit and vegetables, grains and beverages production. It includes refinement, preservation, improvement of product, storage, handling, packaging and canning (Fig. 1). The processing may involve receiving and storing raw or partially processed plant, animal or other food materials, processing the raw materials into finished products, packaging and storing the finished products.

Microscope

A microscope can be defined as an optical instrument consisting of a lens or a combination of lenses for getting magnified images of minute objects. A simple microscope is essentially an ordinary magnifying lens held on an adjustable stand. It can give magnification up to 20 times the size of the object.

A compound microscope consists of two separate lens system, the objective and eye piece (ocular) mounted on a holder known as body tube and with adjustment for illuminating the objects. It gives much greater magnification (100 to 1500 times) when compared to a simple microscope.

Physical Methods of Food Preservation

Conditions too stressful for microbial growth can damage cells. Food environments can be manipulated to inhibit or kill microbes. Physical manipulation of foods can inhibit microbial growth, kill cells, or mechanically remove them from the food. Dehydration, refrigeration, and freezing inhibit microbial growth. Microbes can be killed by heating or ultraviolet (UV) or ionizing radiation. Non thermal energy is also lethal. Membrane filtration removes microbes from liquid foods. This chapter discusses all these physical preservation methods

Physical Dehydration Processes

Drying

When foods are being dried, hot air evaporates the water and carries it away. Both the drying temperature and the decreased water activity (a_w) affect the microbes.

During the initial period of drying, the temperature is still low and the relative humidity is high. The size and composition of the food particle determine the length of this phase. If this particle size is large and the material is dense, this phase can be long, allowing microbes to grow. During later phases of drying, the temperature is high but the relative humidity is low. This provides no opportunity for growth but is not very lethal either. The higher temperatures result in lower moisture content, and dry heat is less lethal than wet heat. If the drying lasts long enough (at least 30 min.), there are time-temperature combinations that kill microbial cells. With certain drying methods, the surface temperature may reach 100°C, while internal temperature remains lower. This kills surface microbes, but not those in the food’s interior.

Bacterial species vary greatly in the ability of their cultures to remain alive after the completion of growth. Some species such as Neisseria gonorrhoeae and Streptobacillus are poorly viable and their cultures usually die out within a few day, whether kept at 37°C at room temperature or at 4-5°C; thus, they must be sub cultivated every 2-4 days for maintenance in the laboratory. Other species are much hardier,. especially sporing species which may remain viable for many years. There are also many non - sporing species (enterobacteriaceae) whose cultures, under suitable conditions, commonly remain viable for many months and often for as much as 10-20 years.

Sterilization is defined as the process by which an article, surface or medium is freed of all living microorganisms either in the vegetative or spore state.

Disinfection means the destruction or removal of all pathogenic organisms, or organisms capable of giving rise to infection. Chemical disinfectants which can be safely applied to skin or mucous membrane and are used to prevent infection by inhibiting the growth of bacteria are called antiseptics.

Five main methods are used for sterilization. 1. Red heat (flaming) 2. Dry heat (hot air) 3. Moist heat 4. Filtration 5. Radiation.

The killing effect of dry heat is due to protein denaturation, oxidative damage and toxic effect of elevated levels of electrolytes. The lethal effect of moist heat is due to the denaturation and coagulation of protein. In the case of spore, steam condenses on it, increasing its water content with ultimate hydrolysis and breakdown of the bacterial protein.

When unwanted organism settle on objects, substances or pure culture is called contamination.

Infection

Invasion of the body of a man or an animal or a plant by disease producing organism. Infectious disease is a condition brought about by an infection of the body by an organisms which is responsible for the disease. Organism that are capable of bringing about infectious diseases are called pathogens while those organism without this capacity are said to be non pathogenic.

Commensals

Organisms on skin and mucous membrane which multiply without causing damage to the tissue.

Subclinical infection / latent infection

When organism enters the tissue and lead to immunity without the appearance of any definite clinical symptoms.

A five-kingdom classification system fails to classify viruses because they are not considered to be living. They neither reproduce independently nor utilize energy

General properties of virus

Viruses differ fundamentally from other classes of microorganism in that:

1.They are ultramicroscopic disease-producing entities.

2.They are simple in structure, basically composed of nucleic acid wrapped up in a protein coat.

3.The genome nucleic acid is either DNA or RNA , either single stranded or double stranded, but never both

4.Viruses have no metabolic activity of their own and lack enzyme systems and other constituents fundamental for independent growth and multiplication.

5.They do not posses ribosomes, nor transfer RNA and enzymes required for synthesis of nucleic acids and proteins.

6.Viruses are incapable of growth and division.

Culture methods employed depend on the purpose for which they are intended. In the laboratory the indications for culture are mainly to

1.Isolate bacteria in pure culture.

2.Demonstrate their properties

3.Obtain sufficient growth for preparation of antigens and for other tests.

4.Type isolates by methods such as bacteriophages and bacteriocin susceptibility.

5.Determine sensitivity to antibiotics

6.Estimate viable counts

7.Maintain stock solution

What are Genes? Genes are linear sequences of nucleotides of DNA (deoxyribonucleic acid). Each gene consists of a specific sequence of nucleotides and is responsible for determining a particular characteristic of cell. Nucleotides consist of nitrogen –containing compounds called bases, joined to the sugar, deoxyribose and to phosphate. The nucleotide bases are the purines, adenine and guanine and the pyrimidines, thymine and cytosine.

A number of genes are joined together to form a structure called a chromosome.

DNA consists of two strands of nucleotides twisted around each other into a double helical structure. The nucleotide bases are arranged in a specific sequence in each strand. The strand has a backbone of sugar and phosphate from which the bases protrude.

Metabolic Processes in Bacterial Cells

All living cells are continually undergoing processes of replication, breakdown, synthesis and repair. The overall term used to describe these processes is metabolism and refers to all the different reactions that must occur in order for a cell to grow and reproduce. The pathways of metabolism are remarkably similar in all living cells. The differences that do occur usually reflect the availability of nutrients or the need for a cell to provide for a specific function. This may be secretion, storage, structural support, energy for movement, or reproduction. Our knowledge of many of the metabolic processes that occur in human cells has been derived from research on the major pathways that also occur in microbial cells.

Catabolism is the process of breakdown of complex molecules, usually with the release of energy. Anabolism refers to the synthesis of new or replacement molecules. This is an energy-requiring process. A metabolic pathway is a series of reactions in the process of metabolism.

The energy from the sun that is trapped and used to produce glucose is released when a molecule of glucose is broken down during metabolism. This complex process is called oxidation, or respiration, and consists of a number of interrelated biochemical pathways, including those of glycolysis, fermentation and aerobic respiration. Reactions that occur in the presence of oxygen are termed aerobic; those that occur in the absence of oxygen are anaerobic. Many of these reactions require the involvement of various cofactors as well as enzymes, and result in the production of energy which is captured by the synthesis of a small molecule called adenosine triphosphate (AT). ATP is termed an ‘energy-rich storage molecule’ because breakdown of ATP releases energy for use in other reactions in the cell.

Growth of a microorganism implies an increase in amount of protoplasm, formation of new structures and eventually formation of new cells. Balanced growth means cell components increase in proportion to each other and unbalanced growth means cell components increase in a non constant relationship to each other

Microbial growth and growth curve

Phases of growth

When bacteria are grown in the laboratory in liquid medium, the medium becomes cloudy or turbid. It is possible to measure the increase in numbers of bacteria at various time intervals and plot the values on a graph representing a growth curve.

Lag Phase: When cells are first inoculated into fresh medium containing all the nutrients they require, they take a short time to adapt before they start to divide. This is termed the lag phase.

Yeasts

Yeasts are non filamentous, unicellular fungi that are typically spherical or oval. Like molds, yeasts are widely distributed in nature; they are frequently found as a white powdery coating on fruits and leaves.