eChapters

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.

Collection and dry preservation of disease samples

Materials : Iron knife, hand lens, vasculum, pruning scissors, paper envelops and plant press with blotters and news papers.

Method

•Collect infected plant parts and place them in paper envelops (use separate envelops for different kinds of diseased specimensxsxs).

•Place envelops in vasculum and bring to the lab.

•Arrange leaves and herbaceous stems inside the folder newspaper sheet.

•Place the newspaper between the blotters in plant press and tighten the bolts.

•After proper drying remove dried specimen from the press and keep them in separate folders.

•Label each folder giving the following informations.

a.Name of the organism

b.Habitat

c.Locality

d.Date of collection

e.Name of collector

f.Collection number

g.Other notes

8.1 Introduction

Egg is a perishable product having short shelf life. The table eggs are of highest quality when they are laid. Preservation of eggs should start from the point of production itself.

The following practices are recommended as routine for the production of quality eggs on the farm.

1. Collection of eggs at least 3 times daily.

2. Using a clean receptacle with ventilated sides and bottom, preferably filler f lats.

Fruits and vegetables grown in kitchen garden or in the field can be preserved in various forms like juice, squash, puree, pickle, jam, jelly, murabba, paste, ketchup, sauce, etc. for year round consumption. Seasonal produce of vegetables and fruits can be preserved through various methods for consumption at a later time.

Juice

Fruits like pineapple, mango, orange, lemon, etc. can be used to prepare juice, squash and other ready to serve beverages. Beverages can be prepared by following various steps. The fruits are washed thoroughly and pat dried with clean cloths. Then the peels are removed wherever necessary. Peeling can be done by hand or by knife. The juice is extracted by using juice extractor or by netting. The extracted juice is then strained using a muslin cloth or mosquito net. To enhance the taste and shelflife, the juice is mixed with sugar syrup. The sugar syrup is prepared by dissolving sugar in water and boiling it. After the syrup is ready, it is allowed to cool and strained through muslin cloth. Then the extracted juice is added with the syrup and citric acid. Preservatives like potassium meta-bisulphite or sodium benzoate is added for storage of the juice. If necessary, essence can be added @ 2 ml/litre of juice. The juice is to be stored in a narrow mouth bottle by leaving a head space of one to two centimetres. The cap of the bottle is to be sealed with wax.

1. INTRODUCTION

Fruits and vegetables represent highly perishable items of agricultural produce, mainly because of their high water content in the fresh form. Fruits and vegetables vary greatly in their protective covering, peel or rind, and also in shape, size, colour, texture and flavour. Their care starts from the field of harvest, including pre- harvest care to reduce postharvest infections and maintain quality. Because of the high rate of perishability in fresh form, fruits and vegetables are preserved by processing into several forms and choices, depending on the specific commodity to ensure reduction in mass, render storage stability for extension in storage life for both domestic and foreign trade over variable distance and time.

Food preservation can be defined as the science which deals with methods of prevention of decay or spoilage of food, thus allowing it to be stored in a fit condition for future use. In this chapter, food preservation and have been discussed in abroad way.

Thus, sugar serves as a preservative in jam and jelly, whereas salt is the major preservative for pickle. RTS (Ready-to-Serve) beverage under acidic conditions in pasteurized form can be stored at room temperature for approximately three months while dehydrated products with 5% residual moisture with suitable packages, depending on the low hygroscopicity can find storage life upto 12 months. Intermediate moisture product with 25% residual moisture is becoming popular to consume mango or papaya strips directly in ready-to-eat form. Storage quality of such forms assumes greater importance. The use of synthetic preservatives is highly questioned in the modern days. However, low concentrations of potassium meta-bisulfite and sodium benzoate are still in use. Formation of benzene under acidic conditions for example in products like RTS beverage by the use of sodium benzoate is said to be dangerous, as benzene is known to be carcinogenic. This takes us to a subject of food safety including hygiene and HACCP. Good manufacturing practices are practically the most useful form of product preparation to expect safety.

When any serious work is undertaken involving the use of living cultures it is necessary to keep these alive for use during the work and for future reference.

This can be done either by growing on a suitable substrate and transferring to fresh media, as the nutrient is used up or by treating the cultures in some way, which halts metabolism until they are revived for use. The former method is time consuming and cultures are at risk whenever they are handled, so various means are devised which can lengthen the periods between sub culturing. The latter methods tend to be complex and expensive.

Preservation of foods including meat and aquatic foods is a creation of conditions for the food articles in such a way to stop or greatly slow down the activities of micro-organisms, chemical and enzymatic reactions and physical forces to prevent the meat and aquatic foods from spoilage while maintaining its nutritional value and sensory attributes.

Significance of Meat Preservation

1. Meat and aquatic foods are perishable food items and are very prone to spoilage and rancidity development due to high nutrients, moisture and neutral pH.
2. Once meat and aquatic foods is exposed to microbial contamination, chemical and enzymatic reactions then it will be very difficult to attain asepsis.
3. To enhance the keeping quality of meat and aquatic foods so that it will be available for further processing.
4. It protects meat and aquatic foods from shrinkage, sweeting and other physical forces.
5. To protect human health by providing the wholesome meat and aquatic foods to the consumers.
6. By this way we can minimize utilization of energy in processing of meat and aquatic foods.

Introduction

Due to inherent composition (high moisture and nutrients) of meat, it is highly perishable in nature. Hence, preservation of meat is essential to maintain its fresh quality. This is accomplished by various preservative techniques based on the principles of temperature control, moisture control and direct microbial inhibition.

Temperature Control

1. Chilling/Refrigeration

In this method, meat is stored at refrigeration temperature of 2 to 5°C. Chilling of animal carcasses is also carried out during ageing process, cutting transit, retail display and even in consumer household before ultimate use. Relative humidity during chilling is kept about 90%. The fresh meat has shelf life of 5-7 days at refrigerated temperature

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

Vegetables consist of a large group of plants consumed as food. These represent complex commodities those include roots, stems, leaves, petioles, bulbs, tubers, corms, rhizomes, flowers buds, immature flowers, seedlings, immature and mature fruits and immature, partially mature and mature seeds of plants (Walker, 1988). Vegetables form an important part of human diet, providing essential minerals, vitamins, fibers and very special phytochemicals and they add a variety to the human diet (Singh, 2007). The consumption of vegetables has increased significantly since the consumers have now become more health-conscious (Cruess, 1958; Brackett, 1987a). Vegetables are cultivated in open fields, greenhouses and soil free hydroponic systems. In terms of retail, vegetables can be sold in a fresh or minimally processed form to provide a ready to eat product.

Vegetables are derived from various parts of plants, and it is sometimes useful to associate different vegetables with the parts of plant they represent. The vegetables based on their parts used as food are given below in Table 20.1.

Fermentation

The decomposition of carbohydrates by microorganisms and enzymes is known as fermentation. During fermentation process of food organic acids and alcohol etc are produced which act as preservatives and also provide fine flavor and aroma that increase the value of raw materials. Most fermented foods contain a complex mixture of carbohydrates, proteins and fats etc. Fermentation occurs when microorganisms consume susceptible organic substances as a part of their own metabolic processes. Natural fermentation is probably oldest form of food preservation.

13.1. Introduction

The preservation by using common salt, spices and vinegar is a common method for preparation of pickles, sauce and chutneys. Salt is mostly used as preservative in pickles in combination with acid. Minimum concentration of salt to act as preservative is about 12%. It inhibits enzymatic browning/discoloration by acting as an anti-oxidant. It exerts its preservative action by:

• Causing high osmotic pressure and thus suppress the microbial cells.

• Dehydrating food by tying up the moisture thus making it unavailable for the growth of microorganisms.

• Salt in the food affects the solubility of oxygen and thus growth of aerobic microorganisms is inhibited

• Chlorine in sodium chloride being good oxidizing agent is toxic to microorganisms

• Salt increases the permeability of the cell wall and thus cause changes in the permeability. Only the haloduric microorganisms can tolerate these effects while others are unable to survive.

• Similarly addition of acid to the food lowers the pH of the food which inhibits the growth of spoilage causing microorganisms.

• Addition of spices and edible oil in these products besides improving flavour and taste also help in preservation.

Introduction
Preservation by using common salt, spices and vinegar is a common method for the preparation of pickles, sauce and chutneys. Salt is mostly used as a preservative in pickles in combination with acid. Sodium chloride is used in brines and curing solutions or is applied directly to the food. The quantity of salt necessary to inhibit growth or harm the cells varies with the type of microorganisms. However, the minimum concentration of salt to act as a preservative is about 12%. Salt (sodium chloride) exerts its preservative action
by performing the following functions:
? Causing high osmotic pressure resulting in plasmolysis of the microbial cells.
? Dehydrating food by tying up the moisture thus making it unavailabl for the growth of microorganisms.
? Salt lowers the water activity and thus has adverse effects on microorganisms.
? Affecting the solubility of oxygen in the food and thus inhibiting the growth of aerobic microorganisms.
? Salt ionizes to yield chlorine ions, which is harmful to microorganisms.
? Chlorine in sodium chloride is a good oxidizing agent & is, therefore, toxic to microorganisms.
 

Preservation of food (fruits and vegetables) in common salt sand vinegar is called pickling. It is one of the most ancient method of preservation of fruits and vegetables. Pickling is the result of fermentation by Lactic acid forming bacteria which are found in large number on the surface of fruits and vegetables. They can grow in acidic medium and in the presence of 8-10 percent salt solution. The growth of majority of undesirable bacteria is inhibited. Lactic acid most active at 30 °C temperature. This temperature should be maintained during the process of pickling.

Preparation of pickles

Pickles are prepared with salt, vinegar and oil or combination of these ingredients. Spices are also used for pickle preparation.

Preserve:- Amature fruits/vegetable or its pieces impregnated with heavy sugar syrup till it become tender and transparent is known as preserve. The fruits like aonla, bael, apple, pear, mango, cherry, karonda, pineapple, papaya are commonly used.

Candied fruit:-A fruits/vegetable impregnated with cane sugar syrup and subsequently drained free of syrup and dried is known as candy. The most suitable fruits are aonla, apple, pear, cherry, karonda, pineapple, papaya are commonly used. In candy the total sugar contains of the impregnated fruits is kept about 75% to prevent fermentation.

Preserves (Murabbas) are prepared from whole fruits and vegetables or their segments by addition of sugar followed by evaporation to a point where microbial spoilage cannot occur. The final soluble solids concentration is reached to about 70 per cent. The finished product can be stored with or without hermetic sealing and refrigeration.

4.1 Overview of Concept and Science

Preserving flowers and plant parts has been a form of artistic expression that was very popular in Victorian ages. Now, this process is moving from an art to a highly interdisciplinary science and has become a major economic activity on a global scale. Because, dry decorative products have been globally accepted as natural, eco-friendly, long lasting and inexpensive as compare to fresh flowers and plant parts, which are perishable and delicate in nature. These perishables cannot retain their fresh like appearance and beauty for several months and it becomes prodigious job to maintain these qualities. Even with preservatives, the vase life of fresh cut flowers has been prolonged to an extent of 40 per cent only. Hence, for those who want the beauty of nature around them in the form of flowers but on a more permanent basis dried flowers are a solution.

Domain of Dried Flowers

Anything from botanicals such as stems, twigs, branches, bark, leaves/ foliage, flowers, thorns/ spines, fruits, cones, seeds, roots; and minor forest products like lichens, fleshy fungi, mosses, selleginnela ferns etc. in a dried form come under the domain of dry flowers. Until a few years ago dried flowers were popular in the West with very few homes in India opting for them. But, today Indian homes have taken to dried flowers in their many forms and shapes like duck to water. There are different segments which are covered under dried flowers (Table 1).

Mental health prevention entails intervening to reduce mental health problems by addressing underlying factors before a specific issue arises in an individual, group or population. The primary objective is to decrease the occurrence of future mental health problems. Mental health promotion and prevention strategies seek to enhance an individual’s emotional regulation capabilities, promote healthier alternatives to risky behaviors, cultivate resilience in managing challenges and adversities and foster supportive social environments and networks. These initiatives lie at the heart of a public health approach to children and youth mental wellbeing, emphasizing the importance of optimizing positive mental health while also preventing and addressing mental health issues.
Adolescence represents a critical period for mental health vulnerabilities. The World Health Organization (WHO) reports that approximately half of all mental health conditions manifest by the age of 14, often remaining unidentified and untreated. Nonetheless, proactive preventive measures can yield significant benefits. The latest WHO report highlights the “numerous opportunities for health promotion and disease prevention during adolescence, which could have positive effects on young individuals in both the short and long term.” The WHO guidance advocates for the implementation of preventive psychosocial interventions among youth to mitigate or prevent the potential longterm consequences of mental health conditions.

Pressing Flowers

One of the most popular methods for drying flowers is to put them under pressure, to remove the moisture out while leaving the color of the flowers and structure intact. There are several ways to apply pressure to flowers. The easiest method is placing them in heavy books and allow for drying. Flower presses can also be used. Some guidelines for pressing flowers in the traditional way are explained below:

A press release, also known as a news release, is a brief, compelling document that provides essential information about an event, product, service, or organization. Its primary purpose is to inform journalists, media outlets, and the general public about noteworthy developments in a way that garners attention and encourages media coverage.
Press releases play a crucial role in public relations (PR) strategies, serving as a bridge between organizations and their stakeholders. They are used across various industries to announce product launches, organizational changes, events, awards, and crisis responses, among other key moments.
The Purpose of Press Releases
Press releases serve as a vital communication tool in modern public relations. They enable organizations to connect with their audience, media, and stakeholders effectively. Below is a detailed exploration of the key purposes they fulfill:
1. Informing the Public
The primary goal of a press release is to convey significant updates, announcements, or achievements to the public.
• Sharing News: Whether it’s launching a product, announcing an event, or achieving a milestone, a press release acts as a formal medium to share this news in a professional manner.
• Transparency: Press releases help organizations maintain transparency by keeping their audience informed about developments. This is especially important for businesses, government bodies, and non-profits that engage directly with the public.