Food Nutrition Hygiene Preservation Notes

THE GALAXY EDUCATION SYSTEMSTD-10

Food and its Nutrients + Food Preservation

Food and its Nutrients

Inroduction

Food is one of the important needs of all living things. You need food to live. Without food you will not be able to live long.

You eat different kinds of foods such as roti,rice,dal,chuntney,papad etc. You also take liquid foods like milk,soups and fruit juices.Whatever may be the food, it is made up of small units which keep you healthy and fit.Hence you should eat food which gives you all the nutrients and keeps you healthy.

In this lesson you will know all about the nutrients and why our body needs them.

Objective After reading this lesson you will be able to do the following:

define "food" and list the functions of food; define "nutrition" and "nutrients"; enumerate the functions and sources of nutrients; explain the importance of water in the body; explain the need for a variety of foods in the diet;

What is food?

We are always thinking about food. This is my favourite food. I will eat this today. But have you ever thought of what is food? Why do you need to eat? Let us answer these questions.What is food?

Anything that we eat and is beneficial for our body is food.

That can be the dhal that you ate or can be beans subji or an idli or can be a bamboo pickle or can be jaggery or sugar that you used in your tea or milk.

Now the second questions is, why do we need to eat food?

Our body is made up of many materials, which we get from the food we eat. Food not only fills up the stomach, it also helps the body to do a number of things.Let us see what these other things are.

Home science std 10 Facilitator : Jasmina Sangani 2010-2011

1. Food gives energy to do work

Everybody needs energy to do work. You need energy for walking, eating, working in the house or outside and for many other activities.You get this energy from the food that you eat.

You need some energy even when are resting. The different organs inside your body are always working : the heart is pumping blood , the stomach is digesting food, the lungs are breathing in air, etc. They also need energy and food provides that energy.

2. Food helps in the growth and repair of tissues

How a small child grows into an adult? The body is made up of thousands of small cells. Lots of new cells are added to these to help the body to grow.

You need food for the formation of new cells. Sometimes cells die or are damaged due to injury. New cells take the place of dead cells and thus the damaged is repaired. Food helps not only to grow but also to do the repair work.

3. Food gives the strength to fight against disease germs

You fall sick when the disease germs enter your body. The food that you eat gives you strength to fight the disease germs and get well again.

4. Food helps in making the body function normally

Various functions that occur on their own inside the body. These are respiration, circulation, digestion, excretion, etc. These and many other process are regulated with the help of food.

Your blood has a certain composition. This can change. Blood may have increased or decreased level of sugar/salt which has to be brought back to normal. Food helps in doing that.

Your heart must beat at a particular rate ie. 72 beats/minute. The excretion of waste products from the body ( carbon dioxide , faeces, etc.) must also be regular. All these are regular by food that you eat.

5. Food satisfies hunger

When you eat food it fills your stomach and you feel mentally and psychologically satisfied. You can yourself recall a situation where eating has given you a lot of satisfaction.


Nutrients and Nutrition

What is nutrition?

N utrition as a science which tells us about what happens to the food when it enters our body and thereafter.

The food that we eat contains many chemical substances. These chemical substances are known as nutrients. So we can say that nutrients are invisible chemicals in the foods which are necessary for keeping the body healthy. These nutrients have different names.

Most of the food contains a mixture of different nutrients, so when the food is eaten your body gets a mixture of nutrients. Each nutrient has a role to play in keeping the body healthy.

Proteins

What does in our body From where do we get

needed for making new cells in the body helps in repairing old and damaged cells helps in healing wounds needed for making blood, enzymes and

hormones also give energy to do work

Animal sources:Meat, egg, fish, poultry,milk, cheese,curd,paneer

Plant sources:All pulses, cereals, peas, soyaben, groundnuts and nuts

The protein from animal sources is known as animal protein and the protein from plant sources is called plant protein. One gram of protein gives 4kcal. An adult needs 1gm of protein for every kilogram of body weight.

Carbohydrates


gives energy hepls to make the food tasty increases the bulk of your food spares the protein to perform other

functions

Cereals – like wheat, rice, bajra, maizePotatoes, sweet potatoes, arbiSweets like sugar, honey, jaggery

Some foods give carbohydrates in your body in the form of starch like cereals, potatoes, sweet potatoes, etc., while some other foods give carbohydrates in the form of sugar like sugar, honey, jam, jaggery, etc.

One gram of carbohydrate gives 4 kcal. An adult person needs 400-420 gms of carbohydrates everyday.


Fats


gives energy – fats are the concentrated sources of energy

help in the utilization of fat soluble vitamins like A,D,E,K

help to keep our body warm make the food tasty provide protection to delicate organs like

heart,liver and also provide padding on our skeleton and muscles.

Milk , butter, ghee, groundnut oil, coconut oil, vanaspati, eggs, liver, meat, fried foods, chocolates, etc.

Like proteins , fats which we get from animals are called animal fats. Fats which we get from plants are called plant fats. Animal fats increase the chances of heart related diseases.

One gram of fat gives you 9 kcal.

Although fats give you more energy than carbohydrates, you eat very little fats and hence fats are not the major sources of energy in your body.

When fats are eaten in large amounts, they make you fat. Food containing large amount of fat can cause stomach upsets. An adult needs only 50-60 gms of fat everyday.

Minerals

Minerals are present in all body tissues and fluids. The minerals calcium and phosphorus are found in bones and teeth. Iron is a mineral which is found in blood as a part of the red pigment haemoglobin.Minerals occur in food as salts.

Minerals have two special characteristics:

Minerals do not provide energy Minerals are not destroyed during food preparation.

There are many minerals which are necessary but we will be studying only a few of them in this lesson.

Calcium and phosphorous are known as macro or major minerals, as they are present in the body in large amounts specially in bones and teeth.

Iron and Iodine are found in the body in smaller quantities, hence are known as micro minerals.

General functions of minerals are-

Maintanance or control of water balance in the body Contraction of muscles Normal functioning of nerves Clotting of blood.


CALCIUM

Functions

Calcium helps your bones to grow and become strong. It makes your teeth grow healthy and strong. It helps the blood to clot. When you get hurt, you bleed.You must have noticed that after

some time the bloood stops flowing and a hard crust is formed. This is called clotting of blood for which calcium is needed.

It also helps in the movement of muscles.

Sources

You get calcium from Milk and its products like butter and ghee. These are the best sources of calcium. Green leafy vegetables like spinach, curry leaves, coriander leaves are also good sources of

calcium.

IRON

Functions

Iron is a very important mineral. It is needed for making red blood cells in your blood.

Sources

You get iron from Green leafy vegetables like spinach, mint, etc. Liver, heart, kidney and egg yolk are full of iron. Gur/jaggery

You must include iron rich foods in your daily diet.

IODINE

Functions

Iodine is needed so that the thyroid gland in your body can work properly.

Sources

You get iodine from Sea foods like fish and sea weeds. Plants which grow in iodine rich soil. Salt which has iodine in it, that is, iodised salt.


V itamins

These are the substances which occur in very small amounts in food, and are essentials for proper functioning of the body. Vitamins cannot be manufactured by the body, therefore must be supplied by the diet.

These are classified into two groups on the basis of their solubility in fats and water. Those vitamins which are soluble in fats are known as fat soluble vitamins.These are

vitamins A,D,E, and K. Those vitamins which are soluble in water are known as water soluble vitamins. These are

vitamins of B group and C.We need all these vitamins in small amounts daily, for the body to work properly. Let us see what each of these vitamins does in our body and where do we get them from.

Vitamins How it works in the body Foods it can be found in

A Your eyes need Vitamin A to see in dim light Its makes your skin healthy Necessary for normal growth and

development Provides resistance to infection.

Vegetables, fruits (especially yellow ones), milk, cheese, eggs yolk, butter, ghee, liver green leavy vegetables.

B Complex

Helps the body to use energy Keeps the digestive system healthy

Pulses, whole grains cereals--wheat,rice,etc

C All the body cells need Vitamin C because it helps to hold cells together.

It also keeps our teeth and gums healthy.

Fruits, leafy vegetables,potatoes,sprouted grams.Guava and amala are the richest sources.

D Work with minerals phosphorus and calciumto make teeth and bones strong.

Oilyfish,milk,cheese,butter,ghee,etc. Our body can make Vitamin D when the skin is exposed to sunlight.

E Prevents tissue breakdown it is an antioxidant.

Whole pulses and cereals

K Main function is in blood clotting process. Green leafy vegetables

Water

Water is not a nutrient, yet it is very important for you. It helps the body cells to do their work. It helps you to digest your food and takes the nutrients from the food to the different cells of

your body. Water also helps to keep your body temperature constant.In summer, extra heat is removed

when you sweat. Water helps to remove the wate products from your body in the form of urine.

Everybody must drink at least 7-8 glasses of water everyday.


Dietary Fibre

Dietary fibre, also known as roughage, is the undigestible carbohydrate present in food. Fibre is present in foods of plant origin only. There are many types of fibre. These can be water soluble or water insoluble. When foods are processed it may remove the fibre as also the vitamins and minerals.Rrice has brown covering over it and is known as brown rice. But the rice which you eat is white rice. Yes the rice has undergone processing and the brown coat is removed. So also is the fibre and some Vitamins.

Wheat atta is something you use everyday. Some people have the habit of sieving the atta and then making chapaties out if it. But in the process, what happens is that you remove the wheat bran which is fibre and the atta becomes refined. When this refined flour is eaten it is not so beneficial for your health.

Fibres perform many essential functions in the body. they increase the bulk and softness of the stool,thus making it easier to pass; foods which contain fibre require more chewing and thus have a high degree of satiety.

High fibre diet helps in the prevention of-Constipation ,Haemorrhoids Cancer of the large bowel,Diabetes mellitus,Obesity

Food rich in fibre are: whole wheat atta,dalia(porridge) fruits such as guava,apples,pineapples,banana pulses,dhals,rajmah,lobia,whole dhals vegetables such as peas,beans,carrots,cauliflower,green leafy vegetables.

Five Food Group System

Food Group Food Stuffs Make Nutrients

Cereals Rice,wheat,ragi,bajra,maize,jowar,barley,riceflakes,wheat flour.

Energy,protein,invisible fat,Vitamin B, iron,fibre

Pulses Bengalgram,blackgram,greengram,redgram,lentil(whole as well as dhals),cowpea, peas, rajmah, soyabeans,beans,etc.

Energy,protein invisible fat,Vitamin B,calcium,iron,fibre

Milk,egg and flesh foods

Milk: curd,milk,cheese,paneerMeat: Chicken,liver,fish,egg,meat

Protein,fat,Vitamin-B calcium

Fruits and Vegetables

Fruits:Mango,guava,tomato ripe,papaya,orange,sweet lime,watermelonVegetables(Green Leafy):Amarnath,spinach,gogu,drumstick leaves,coriander leaves,mustard leaves,fenugreek leaves.Other Vegetables:Carrot,brinjal,ladies fingers,capsicum,beans,onion,drumstick, cauliflower

Vitamin A,Vitamin-C fibre

Invisible fats, Vitamin A, Vitamin B, calcium, iron, fibre

Vitamin A,calcium,fibre

Fats and Sugars Fats:Butter,ghee,hydrogenated oils,cooking oils like ground nut,mustard,coconut.

Energy,fat


Sugar:Sugar,jaggery Energy

HYGIENIC PREPARATION OF FOOD

The four golden rules of food hygiene are:

1 Buy food from a safe source. 2 Prevent bacteria from entering your food. 3 Prevent the multiplication (or growth development) of bacteria in your food. 4 Destroy bacteria on food, utensils and work surfaces

Rule No.1

Buy food from a safe source. Make sure that you buy food only from a supplier who is well known and reputable. It is impor-

tant to check that all foods be within their expiry date and kept in appropriate conditions in the shop.

Serving counters should be kept spotlessly clean, likewise machines such as knives and slicing machines.

Freezers, fridges and chillers should display their temperatures and should be set at less than 5 degrees centigrade for chilled products and -18 degrees centigrade or less for frozen products.

All packaging should be original and not tampered with or forged. This would indicate that the product is not the original contents and has been produced by a fraudulent company. Do not buy these products under any circumstances because they threaten your health.

All reputable retail businesses that sell food should display up to date licences from all the re-quired regulatory authorities as required by law.

Rule No.2

Prevent bacteria from entering your foodAll bacteria, when they have the right conditions begin to multiply.

The conditions that they need are,a) a temperature of above 10 degrees centigrade, (some say 5 degrees).

b) A food source. Bacteria need only 20 minutes to adjust themselves to a new food source. For example, Supposing a bacteria was on a sugary food and suddenly found itself on fish, the transition the bacteria would need to be able to digest the new food source is twenty minutes.

c) A source of water.On acquiring suitable conditions bacteria then commence to reproduce at a rate of one division of the whole colony every 20 minutes. e.g. If you had 1000 bacteria on a piece of food to begin with, you will have one million bacteria after 20 minutes. Keeping bacteria from getting into your food is primarily down to prevention of cross contamination.As home owners we do not usually have this luxury therefore it is advised to keep cooked foods at the top of the fridge and raw materials at the bottom in closed containers. This way the risk of contamination is greatly lessened.Eggs, especially, should be kept in a closed container because they have many bacteria on their outer shells.Remember to wash your hands and arms to the elbow before preparing food. Cut your salads first and then go onto the foods that are to be cooked making sure to thoroughly wash your board before moving on to different types of food.Wash all surfaces before and after work with a good detergent. Put cloths into the wash after each usage. Always start with a clean cloth.


Rule No.3

Prevent the multiplication of bacteria in your food.

As Stated above bacteria need the correct conditions to divide themselves. To do this they need A) the right temperature, B) Food and C) water.

It follows, then, that food should be stored at the lowest possible temperature to keep bacteria inactive. Also, do not allow your food to come into contact with water before you cook it. By thawing food in water we are giving the bacteria a heads start.

Cook your food at the earliest possible moment and after it is cooked keep it at a temperature of at least 70 degrees centigrade until it is served.

If you have to cool your food, do not put hot food in large containers into the fridge. Divide it up into smaller containers and do not stack them in such a way that air cannot circulate around the containers. Once cool freeze if possible.

When thawing food, do it in the fridge in a closed container. Remember, it's better to plan a meal a couple of days ahead of time than to have have to take couple of sick days off work in bed.

Once thawed (soft), cook the food as soon as possible. The best way to destroy all bacteria is to cook your food in a pressure cooker. This way the

combination of increased temperature and increased atmospheric pressure will completely sterilize the food.

Rule No. 4

Destroy bacteria on food, utensils and work surfaces. This rule speaks for itself. Do not let them develop in your kitchen. Cook food as quickly as possible. Food that cannot be cooked should be frozen if it is not eaten

within a short space of time. Alternative forms of food preservation such as, dehydration, smoking, canning, sterilizing,

concentrating and pickling are all alternative ways of preventing the development of and destroying bacteria in food.

The surroundings also constitute a source of food contamination; therefore, you should wash your work surfaces after each usage with hot water and detergent.

In professional kitchens, all working areas should be surfaced with stainless steel. This way, the surface may be cleaned with special grease and lime removing chemicals that have either a caustic soda base or a phosphoric acid base. For safety, remember never to mix chemicals; especially acids and alkalis like caustic soda and phosphoric acid.

Likewise wash all utensils in very hot water and washing up detergent. The water should be so hot that you need gloves to tolerate the heat.

Store pots, pans, plates, cutlery and other utensils in a clean and dry place. Make sure that they are dry before storing them away. Use a clean dish towel every time. Store them upside down. Keep all storage areas clean. Check regularly for signs of vermin (pest).

Heat crockery to 80 degrees centigrade before serving. This will prevent contamination even further.

These are the four principles of good food hygiene. Follow them closely and the chances of you or your clients becoming sick are substantially lessened.


Food Preservation

Objectives

After reading this lesson you will be able to: define food preservation state the significance of food preservation enumerate causes of food spoilage describe general principles of food preservation explain the importance of hygienic handling of food describe methods of preserving food at home.

What is Food Preservation?

The dictionary meaning of the word 'preserve' is to keep safe,retain quality,prevent decomposition or fermentation. When we apply this meaning to food preservation it can be defined as:-A process by which certain food like fruits and vegetables are prevented from getting spoilt for a long period of time.The colour,taste and nutritive value of the food is also preserved.

Food preservation means to keep food for a limited period of time without decaying.

Food gradually undergoes deterioration from the time it is harvested or manufactured . Deterioration of food makes it unsafe and unfit for human consumption.

Why Do We Need to Preserve Foods ?

Let us take the example of a fruit, say mango. There are many ways by which mangoes can be preserved. These are :-juice,mrraba,squash,aam papad,pulp,chutney,pickle,raw mango powder.

Mango is a summer fruit and grows in large quantities during the months of April to August. Different varieties of mango are grown in different parts of our country.Usually all the quantity grown in a region cannot be consumed by the people staying there as there is always an excess. What does the farmer do with this excess quantity ? He makes arrangements to transport the excess quantity to regions where either mango is not grown or where the particular variety of mango is not available. If he does not do this, the excess produce will rot and go waste. The farmer will then lose money.

There is still some quantity which is left after the fresh fruit is consumed by the people.It is this quantity which has to be preserved which has to be preserved for consumption during the months when mango is not available.Preservation of foods is done during the months when food is available in large quantity and therefore at low cost.

One of the important reasons for preserving foods is to take care of the excess produce.

There are many other reasons for preserving foods.Let us learn about these.


STORAGE OF FOOD

Proper storage of food is imp to prevent from spoilage and also food poisoning. It has to be done under proper temp and humidity condition and used as soon as possible.

Refrigerator is the best storage device at home to keep fresh, perishable and cooked food.

Grain, legumes (pulses), flour must be kept cool and dry to prevent microbial attack. When stored properly, grains and legumes can stay for long period without nutritional changes

Vegetables:potatoes ,onions and other root veg can be stored in cool well ventilated area

All other veg like brinjals, lady finger should be washed ,drained and kept in plastic bag container

Green leafy veg should not be washed before storage in plastic moisture proof bags

Fruits

Ripe fruits except banana can kept in the refrigerator to e stored in the refrigerator

Fruits like grapes,cherries should not be washed before storage. They can be kept in shallow container.

Frozen foods can be stored in the freezer. Dried fruits are generally stored in the air tight container> Canned open fruits can be transformed into glass container and kept in refrigerator to retain the flavor. Over ripened fruits should not be kept for a longer period as they are the source of infection.

Milk and Milk Products

All the dairy products should be kept cold ,clean and covered. They should be stored in the coldest part of the refrigerator –frozen

Eggs

Eggs should be washed properly before storage to remove dirt, which may contain bacteria. Broken or cracked eggs should be used as soon as possible.

Meat,Fish and Poultry

Uncooked meat , fish poultry should be kept covered by wrapping in moisture proof paper. Cooked meat , fish and poultry can be kept in the freezer within air tight container.

What is food spoilage?

Food spoilage means the original nutritional value, texture, flavour of the food are damaged, the food become harmful to people and unsuitable to eat.

Causes of food spoilage

a. Microbial spoilage

There are three types of microorganisms that cause food spoilage -- yeasts, moulds and bacteria.

Yeasts growth causes fermentation which is the result of yeast metabolism. There are two types of yeasts true yeast and false yeast. True yeast metabolizes sugar producing alcohol and carbon dioxide gas. This is known as fermentation. False yeast grows as a dry film on a


food surface, such as on pickle brine. False yeast occurs in foods that have a high sugar or high acid environment.

Moulds grow in filaments forming a tough mass which is visible as `mould growth'. Moulds form spores which, when dry, float through the air to find suitable conditions where they can start the growth cycle again.

Mould can cause illness, especially if the person is allergic to molds. Usually though, the main symptoms from eating mouldy food will be nausea or vomiting from the bad taste and smell of the mouldy food.

Both yeasts and moulds can thrive in high acid foods like fruit, tomatoes, jams, jellies and pickles. Both are easily destroyed by heat. Processing high acid foods at a temperature of 100°C (212°F) in a boiling water canner for the appropriate length of time destroys yeasts and moulds.

Bacteria are round, rod or spiral shaped microorganisms. Bacteria may grow under a wide variety of conditions. There are many types of bacteria that cause spoilage. They can be divided into: spore-forming and nonspore-forming. Bacteria generally prefer low acid foods like vegetables and meat. In order to destroy bacteria spores in a relatively short period of time, low acid foods must be processed for the appropriate length of time at 116°C (240°F) in a pressure canner. (Temperatures higher than 100°C [212°F] can be obtained only by pressure canning.)

Eatting spoiled food caused by bacteria can cause food poisoning.

Enzymes

Enzymes are proteins found in all plants and animals. If uncooked foods are not used while fresh, enzymes cause undesirable changes in colour, texture and flavour. Enzymes are destroyed easily by heat processing.

Oxidation by air

Atmospheric oxygen can react with some food components which may cause rancidity or color changes.

c. Other factors

Infestations (invasions) by insects and rodents, which account for huge losses in food stocks.

Low temperature injury - the internal structures of the food are damaged by very low temperature.

IMPORTANCE OF FOOD PRESERVATION

A process by which certain foods like fruits and vegetables are prevented from getting spoilt for a long period of time. The colour, taste and nutritive value of the food is also preserved

One of the important reasons for preserving foods is to take care of the excess produce. The second reason for preserving foods is that they add variety to our meals.


http://home.pacific.net.hk/~ppleung/Chem/food%20poisoning.htm

Reaches areas where the food item is not grown. For example inclusion of dehydrated peas, green leafy vegetables, canned fruits etc, in the meals is a good idea in such areas

Makes transportation and storage of foods easier. Preservation of foods usually reduces bulk. This makes their transportation and storage easier since it requires less space. For ex-ample, if you dry green leafy vegetables such as mint, methi, corriander, etc, their weight and volume reduces, thus making their storage easy.

METHODS OF PRESERVING FOOD

PRINCIPLES OF FOOD PRESERVATION

Removal of micro-organisms or inactivating them-This is done by removingair, water (moisture), lowering or increasing temperature, increasing the concentrationof salt or sugar or acid in foods.Inactivating enzymes-Enzymes found in foods can be inactivated by changingtheir conditions such as temperature and moisture, when you preserve peas, oneof the methods of preservations is to put them for a few minutes in boiling waterRemoval of insects, worms and rats-By storing foods in dry, air tight containersthe insects, worms or rats are prevented from destroying it.

Foods can be preserved at home by the following methods-(i) Dehydration(ii) Lowering temperature(iii) Increasing temperature(iv) Using preservatives

Dehydration: The word dehydration means removing water or moisture from foods. The home method of dehydration is sun dryingSome foods are dried as they are, eg, green leafy vegetables (methi, pudina, corrianderetc.) cauliflower, grapes, amla, onion, raw mango, etc. Some foods are cooked andthen dried. For example potato chips, papad, banana, chips, wadis, etc. The mostappropriate weather to dry foods is when the air is dry and there is strong sunshine.

Low Temperature: Using low temperature to preserve foods works on the principle that low temperature slows microbial and enzyme action. The food is thus prevented from spoilage.Foods can be preserved at low temperature by:(1) Refrigeration 40 C to 70 C(2) Cold storage – 10 C to – 40 C(3) Freezing –180C or belowThe duration for which the food can be preserved by using low temperature varies withthe type of food and the temperatures. The lower the temperature, longer is the durationfor which food can be preserved. Of the three methods, freezing uses the lowesttemperature.

Increasing TemperatureBy increasing the temperature, enzymes and micro organisms are destroyed, leavingthe food safe from spoilage.

There are mainly two methods of preserving foods by using high temperature-(1) pasteurization


(2) sterilization

Pasteurization: In this method food is heated to a high temperature and then quickly cooled. Themicro-organisms are not able to withstand the sudden change in temperatureand are destroyed. However, some organisms still survive this method.

Sterilization: The high temperature used in this method destroys all the microorganismsin the food. The foods are exposed to high temperature for longer time and in some cases under pressure.When a pressure cooker is used to cook, the food lasts longer because most microorganismsget destroyed. You can also sterilize bottles and other equipments used

Using PreservativesWhat are preservatives?Any substance that is added to foods to make it last for a longer time is called aPreservative by increasing the concentration of salt, sugar or acid in a food preventsits spoilage. Therefore, salt, sugar or acid are substances which act as preservatives.

There are two types of preservatives:-(1) Natural Preservatives: Salt, sugar, lemon juice, vinegar, oil and spices are naturalpreservatives.(2) Chemical preservatives: Potassium metabisulphate, citric acid and sodium benzoateare chemical preservatives.

Natural preservatives:(a) Salt: When you make pickle at home, salt is one of the ingredients used.Besides adding to taste, salt has a specific function, i.e., to act as a preservative. If the proportion of salt in picklesis less, it can get spoilt after sometime. Increasing the quantity of salt in the food changes its composition .Due to the presence of salt in the food, osmosis takes place. As a result, water comes out of the food. When there is no or less water in the food, the micro organisms are not able to grow and the food becomes safe. Salt also reduces the activity of enzymes, thus preventing the food from getting spoilt.Salt is used as a preservative in pickles, chatni, sauce, canned food, etc. Salt is rubbed on fish which helps to preserve it.

(b) Sugar: These are jams, jellies, murabbas, squashes. Like in pickle, chatni,etc., sugar is added to these foods not only for taste but also as a preservative. The proportion of sugar has to be correct to protect them from spoiling.

(c) Acids: These are lemon juice, vinegar, citric acid, etc. Vinegar is used to preserve onions, tomato ketchup; lemon juice is used in pickles; citric acid is used in squashes. Acids increase the acidic content of food items, thus preventing the activity and growth of micro-organisms.

(d) Oils and spices: These are used as preservatives in pickles. Mustard powder is one of them. It prevents the growth of micro organisms, thus preventing spoilage.When pickle is made at home, have you observed that oil is poured to cover themango, lemon or other vegetables which are being pickled. The oil acts as a protective cover and has two advantages-(i) prevents contact of micro-organisms with the food, hence they can not spoil the food.


(ii) prevents contact of air with food, hence the micro organisms can not grow and spoil the food.

What You Have Learnt

FOOD AND ITS NUTRIENTS

Functions of food + Nutrients and Nutrition Proteins Carbohydrates Fats Minerals Vit Water Dietary Fibre

Five Food groups

Hygienic Preparation of food -4 Rules

FOOD PRESERVATION

MEANING

NEED CAUSES OF FOOD SPOLAGE

PRINCIPLES OF FOOD

PRESERVATION

METHODS OF PRESERVATION AT HOMEDehydration Lowering Increasing Preservatives

Temperature Temperature Natural Chemical

Refrigeration Cold storage Freezing Pasteurization Sterilization.

WEBSITE TO VISIT http://www.nios.ac.in/SecHmscicour/english/LESSON_05.pdf


http://www.nios.ac.in/SecHmscicour/english/LESSON_05.pdf

What You Have Learnt

FOOD AND ITS NUTRIENTS

Functions of food + Nutrients and Nutrition Proteins Carbohydrates Fats Minerals Vit Water Dietary Fibre

Five Food groups

Hygienic Preparation of food -4 Rules

FOOD PRESERVATION

MEANING

NEED CAUSES OF FOOD SPOLAGE

PRINCIPLES OF FOOD

PRESERVATION

METHODS OF PRESERVATION AT HOMEDehydration Lowering Increasing Preservatives

Temperature Temperature Natural Chemical


Refrigeration Cold storage Freezing Pasteurization Sterilization.

WEBSITE TO VISIT http://www.nios.ac.in/SecHmscicour/english/LESSON_05.pdf


http://www.nios.ac.in/SecHmscicour/english/LESSON_05.pdf

Food Nutrition Hygiene Preservation Notes

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