eChapters

Introduction

Food packaging is one of the most dynamic and fast-growing industries in the current scenario of increasing industrialization. With the constant upsurge in the food wastage at different stages of processing (suchas harvest, storage, processing, transportation, and distribution) leads to more than 15% of food produced ending up in the dumping grounds due to food spoilage caused by climatic conditions andmicroorganisms.Ever-increasing demands of consumers for convenient food makes packaging technology a need of the hour in order to keep the food safe, wholesome and of high quality at the same time.

So appropriate packaging has the potential of not only preventing spoilage but also taking care of healthand well-being of the individuals.Therefore, packaging plays the most important role in the overall safety of the food product.This makes packaging as the ever-evolving field since new requirements need new materials which demands new approaches and technology for better quality products.

By definition, Food packaging is a well-organized system of protecting the food product from any kind of physical, chemical, and biological damage in order to ensure that food reaches the consumer in its most safe condition at minimum applicable cost. It is bridge between production and consumption (Paine, 1992).

Sprinkler irrigation is an advanced method of irrigation in which water is sprayed to air and allowed to fall on the ground similar to rainfall. The spraying of water occurs through nozzle connected to a network of pipes with water under pressure. The rate of application and area of coverage under a sprinkler is regulated by suitable selection of nozzle size and pressure in the system.

History of Sprinkler Irrigation

The sprinkler irrigation has started elsewhere in the world in the early part of twentieth century. Before 1920, sprinkler irrigation was limited to orchard, nurseries and intensive vegetable cultivation. The cost of sprinkler reduced considerably by the development of impact sprinkler and lightweight steel pipe with quick couplers in the 1930s. As a result, sprinkler irrigation began to spread in larger area and to the area of field crops. However, sprinkler irrigation developed mainly after the Second World War with the introduction of lightweight portable aluminum pipe.

Sprinkler irrigation has started in India from mid of 1950s. Due to requirement of high initial investment, the average Indian farmers cannot afford the system and therefore the area under sprinkler irrigation in India was 0.66mha (approx.) out of total irrigated area of 87.80mHa in 1995 (INCID). The sprinkler irrigation was first introduced in India in hilly regions such as Western Ghats in Kerala, Tamil Nadu, Karnataka and in the North Eastern States especially by plantation owners for irrigating tea, coffee and cardamom crops. Since the cost of aluminum pipe is high, to replace it, High Density Polyethylene Pipe (HDPE)/PVC with suitable modification have been introduced in sprinkler system. However, the area under HDPE/PVC piping system is below 20% to the total area under sprinkler irrigation. The remaining area is cultivated under aluminum or steel based sets. The indigenous manufacturing of the system has started in India only 35-40 years ago and there are about fifty numbers of manufacturers till 1996 (INCID). The details of the cultivated area under sprinkler irrigation system in the world and in Indian States are given in Table 8.1 & 8.2 respectively.

Drip system has great promise for efficient utilization of available irrigation water. In our country and elsewhere in the world the scientists are unanimously agreed to adopt drip irrigation method for higher application efficiency and thereby better use of scarce irrigation water. Saksena (1993) reported water losses of only 1-2% in drip irrigation in comparison to 6-9% in sprinkler and 30-35% in surface irrigation method. However, very small area compared to other methods of irrigation so far is irrigated by drip system in our country. Up to 2000 the total area under drip irrigation was 2,59,600 ha in India (Alam & Kumar, 2000). Initial high investment for drip network and pumping system, of course, are discouraging to the most of our farmers. Sharma & Abrol (1993) mentioned that in spite of the very encouraging results and attractive subsidies offered by the Govt. of India, the adoption of the drip irrigation system has not picked up to the expected level. Along with the other reasons they pointed out the high initial cost of the system and lack of research effort on developing cost-effective design suited to local condition are responsible for non-practice of drip irrigation at a considerable scale.

Some research works has been conducted to find out low cost method of drip irrigation. Biswas (1998) developed a manually operated drip irrigation system made of bamboo mains, laterals and sub-laterals. The system and its performance are described below.

Drip Network

The main and laterals of the drip network were made of hollow bamboo pieces each of 3m lengths with 7.5cm and 4.0cm diameter respectively. The sub lateral or the emitters were the bamboo twigs of 0.25cm inside diameter and 1.05-1.10m length to suit the spacing between the plant rows. The mains and laterals were made for the required length in the field by jointing together the sections one after another (Fig. 7.1). The ends of two sections, which contact each other, were made such that one section easily gets inside the other for about 10-15cm.

Introduction

Fertilization is the application of fertilizer for the benefit of the crops. It may be traditional broadcasting or fertigation. In broadcasting method the fertilizer is applied in concentrated granular form. The size of the granules ranges from granular dust to pellet size. These solid fertilizers get dissolved by the rain or irrigated water to leach down the plat root zone. This method results uneven nutrient delivery due to uneven dissolving the fertilizer granules. It may cause burning of plant leaves and root system due to uneven and uncontrolled release of nutrients. Dry fertilizers can volatilize and release gases which may damage or burn the nearby foliage. Availability of fertilizer to the plant root zone largely depends on the temperature and availability of water to dissolve the fertilizers.

In fertigation liquid or water-soluble fertilizer, soil amendments or other products required by the plants is either sprayed on to the plant material or applied to the plant bottom with irrigation water. Foliar application provides high rate of absorption of fertilizer through the leaf/stalk/branch structures of plants. Ground application also provides good consistency in making its way to root zone and plant absorption. Thus, the fertigation provides benefit of increased nutrient absorption; decrease water needs, and reduce the fertilizer and chemical use (Anonyms, 2005).

Introduction

There is different type of distributors available in the market. Depending on the basic principle of working they may be broadly classified into three major groups as below (FAO, 1980).

i. Distributors in which head loss takes place through small diameter tubes

ii. Distributors in which head loss takes place through some orifice control

iii. Distributors in which head loss takes place through a vortex action

There are many adaptations to distributors though the working distributors fall under the above stated basic principle. Tiny perforation in the laterals or porous materials allows leaking out the water serves the purpose of distributors. The compensating type distributors have long path in it to dissipate the energy and drips almost same rate within certain range of pressure variation. Whatever may be the distributors proposed to be used, the discharge characteristics should be known. The discharge characteristics should be provided by the manufacturers and preferably certified by any authorized body; otherwise to be tested by the designer before recommendation to large-scale use.

The pipe network in a drip system consists of a mainline, sub mains, laterals, and distributors. The layout of the pipes depends on the physical factors like shape and size of the area, topography and any other obstacles in the field. In any field there may be the scope of different layout of the pipes. The most economic one should be selected. In general, contour line is followed in laying the laterals in sloping land, sub main length usually be shorten in uphill and equally spaced laterals on either side of a sub main in a flat land provides good layout.

Hydraulic Formulae /Head Losses in Pipes

There are numerous equations for solving the head loss in pipes. The most commonly used are the Darcy-Weisbach, Hazen-William and Scobey’s.

Crop Water Requirements

In designing an irrigation system, the primary objective is to know the water requirement of crops. Water requirement of crops are determined either by f ield cultivation or by estimation through commonly used empirical formulae such as Blaney Criddle, radiation, Penman or pan evaporation method.

Definitions

Crop water requirement or evapotranspiration (ETcrop ): It may be defined as the rate of evapotranspiration of a disease free crop growing in a field of not less than one hectare under adequate fertility and water supply so that full productive potential can be achieved in prevailing environment. Evapotranspiration requirement of a crop refers the ETcrop and expressed in mm/day.

Reference crop evapotranspiration (ET0 ): It is the rate of evapotranspiration from an extended surface of 8 to 15cm tall green grass of uniform height, actively growing, completely shading the ground and not short of water. ET0 may be computed by using the empirical formulae and meteorological data for the specific period.

In drip irrigation water is distributed throughout the field from a system of pressurized pipelines. The pressure must be sufficient to overcome the frictional losses and elevation differences. The system also deserves discharge from all the emitters and the emitters must dissipate the pressure difference between the inlet to emitters and atmospheric pressure.

The flow through the drip pipes may be laminar or turbulent or a combination of both. The laminar flow is characterized by the layers of cylindrical tubes of which the maximum velocity is at the center about double of the average velocity. The turbulent flows having pulsatory cross current velocities and maximum velocity is about only 1.25 time of the average velocity. Turbulent f lows loss more energy than laminar flow due to development of the cross current velocity.

Reynolds Number

The criterion for distinguishing the flow from laminar to turbulent was developed by Osborne Reynolds (1842-1900) and was named as Reynolds number; Re . The Reynolds number in circular pipes flowing full is expressed as

Introduction

Drip irrigation is an efficient method of application of water at the plant bottom at a rate nearly equal to the consumptive use rate of the plant, thereby minimizing the conventional water losses like percolation, runoff and evaporation from soil. It is a process of slow application of water on, above or beneath the soil by the surface, sub-surface, bubbler, and spray or pulse system. Fertilizer can also be applied with the drip water. Emitters or applicators are placed closed to the plants and used to spray water in the form of drops, tiny streams or miniature spray. In the drip system water applied from the point source advances in all direction in the soil outward from the source. Drip irrigation is essentially a low rate, low pressure, frequent and long duration application of water in plants root zone area.

Drip irrigation is also called as localized irrigation, trickle irrigation, daily f low irrigation, diurnal irrigation, drop irrigation, sip irrigation, and micro irrigation. A particular name is being popularized in any area depending on the choice of the people of that area. The International Commission for Irrigation and Drainage (ICID) has recommended the term micro-irrigation while the American Society of Agricultural Engineers (ASAE) has preferred drip irrigation. In India it is told as drip irrigation.

• General Consideration

• Post-mortem examination of large animals

• Post-mortem examination of poultry

• Steps in post-mortem examination

• Writing of post-mortem report

• Collection, preservation and dispatch of specimens for laboratory diagnosis

General Consideration

Necropsy is examination of animal after death also known as post mortem examination. It helps in diagnosis of diseases and their control. It is said that “Necropsy is a message of wisdom from dead to living”. Necropsy include systemic examination of dead animal, recording of pathological lesions, their interpretation to make diagnosis of disease. Sometimes it is difficult to arrive any conclusion merely based on gross examination of dead animal. Then one should seek the help of laboratory examinations such as Histopathology, Microbiology, Immunology and Toxicology for confirmation.

• Neoplasm General

• Neoplasm in cattle and buffaloes

• Neoplasm in sheep and goat

• Neoplasm in equines, swine and camels

• Neoplasms in pet animals

• Neoplasms in poultry

• Neoplasms in wild animals

• Neoplasms in laboratory animals

Concretions

Concretions are solid, compact mass of material, endogenous or exogenous in origin, found in tissues, body cavities, ducts or in hollow organs. Concretions are stone-like bodies commonly occur in urinary system, gall bladder and gastrointestinal tract. Concretions of endogenous origin are known as calculi while those formed from exogenous material are known as piliconcretion (Hair), phytoconcretion (plant fibres) and polyconcretion (polythenes).

Calculi

Calculi are formed due to deposition of salts around the nucleus/nidus consisting of either fibrin, mucus, desquamated epithelial cells or clumps of bacteria. Due to the gradual and repeated precipitation of salts, calculi become laminated. In the process of calculi formation, the inner structural arrangement gets shrink, producing a rough superficial surface. Calculi formation is more common in urinary system and in gall bladder of man and animals; however, they may also occur in salivary gland, pancreas and intestines.

Aplasia/Agenesis

Aplasia or agenesis is absence of any organ (Fig. 9.1).

Hypoplasia

Hypoplasia is failure of an organ/tissue to attain its full size (Fig. 9.1).

Etiology

• Congenital anomalies e.g. hypoplasia of kidneys in calves.

• Inadequate innervation.

• Inadequate blood supply.

• Malnutrition.

• Infections e.g. cerebral hypoplasia in bovine viral diarrhoea.

Calcification

Calcification is the deposition of calcium phosphates and calcium carbonates in soft tissues other than bones and teeth. It may be classified as dystrophic and metastatic calcification.

Dystrophic Calcification

Dystrophic calcification is characterized by the deposits of calcium salts in necrosed tissue of any organ (Fig 8.1).

Etiology /Occurrence

• Necrosis.

• Parasitic infections.

• Tuberculous lesions.

Immunity

Immunity is the resistance of body against extraneous etiological factors of disease, which is afforded by the interaction of chemical, humoral and cellular reactions in body. This is an integral part of the body without, which one cannot think of life. During the process of evolution, nature has provided this defense mechanism in the bodies of all living creatures particularly of higher animals and man, that protects them from physical, chemical and biological threats. It can be classified as natural or paraspecific and acquired or specific immunity.

Natural/paraspecific immunity

There are some species which are resistant to particular diseases due to presence of natural resistance against them e.g. horse, pig, cat are resistant to canine distemper virus; dogs are resistant to feline panleucopenia virus, chickens are resistant to anthrax. Even within species, there is natural resistance that protects some individuals while others are susceptible e.g. Indian deshi cattle Zebu (Bos indicus) is quite resistant to piroplasmosis in comparison to Bos taurus. Besides, there are the mechanisms or barriers in body provided by nature.

Inflammation

Inflammation is a complex process of vascular and cellular alterations that occur in body in response to injury. The term inflammation has been derived from the Latin word inflammare, means to set on fire. Inflammation is considered as an important event in body that activates the existing defense mechanisms in circulating blood to dilute, naturalize or kill the irritant/ causative agent. Thus, it is said that immunity is the resistance of body, while inflammation is the activation of that immunity. It is beneficial to body except when chronic or immune origin. Inflammation starts with sublethal injury and ends with healing.

Etiology

• Any irritant/ injury.

• Bacteria, virus, parasite, fungus etc.

• Trauma. • Physical or chemical injury.

Necrosis

Local death of tissue /cells in living body is known as necrosis, It is characterized by the followings.

• Pyknosis is condensation of chromatin material, nuclei become dark, reduced in size and deeply stained.

• Karyorrhexis is fragmentation of nucleus.

• Karyolysis is dissolution of nucleus into small fragments, basophilic granules/fragments.

• Chromatolysis is lysis of chromatin material.

• Necrobiosis is physiological cell death after completion of its function e.g. RBC after 140 days.

Necrosis is further classified into coagulative, caseative, liquifactive and fat necrosis which are different from apoptosis (Figs. 5.1 to 5.3).

Cloudy Swelling

Swelling of cells occur with hazy appearance due to a mild injury. The cells take more water due to defect in sodium pump leading to swollen mitochondria which gives granular cytoplasmic appearance. It is the first reaction of cell to the mildest injury. Cloudy swelling is a reversible reaction (Figs. 4.1 & 4. 2).

Etiology

• Can be caused by even mildest injury.

• Any factor causing interference with metabolism of the cell like bacterial toxins, fever, diabetes, circulatory disturbances etc.

Macroscopic features

• Organ becomes enlarged and rounded.

• Weight of organ increases.

• Bulging on cut surfaces.

• Amount of fluid increases in organ.

Microscopic features

• Swelling of cells, edges become rounded.

• Increased size of cells.

• Cytoplasm of the cells becomes hazy/cloudy due to increased granularity.

• Can be seen in liver, kidney and muscles.

Congestion/ Hyperemia

Hyperemia is increased amount of blood in circulatory system. It is of two types, active and passive. In active hyperemia blood accumulates in arteries while in passive hyperemia the amount of blood increases in veins (Figs. 3.1. to 3.4).

Etiology

• As a result of inflammation.

• Obstruction of blood vessels.

Macroscopic features

• Organ becomes dark red/cyanotic.

• Size of organ increases.

Etiology

Etiology is the study of cause of disease. It gives precise causal diagnosis of any disease. Broadly, the cause of diseases can be divided into two

a. Intrinsic causes.

b. Extrinsic causes.

Intrinsic Causes

Those causes which determine the type of disease present within an individual over which he has no control. These causes are further divided into following subgroups:

Genus

Specific diseases occur in a particular genus or species of animals. e.g. Hog cholera in pigs, Canine distemper in dogs