Farming (Agriculture and Animal husbandry)

Introduction 

Globally there is a rapid increase in the production and consumption of livestock products and which is expected to continue growing. However, increasing productivity, especially in the small to medium production system, is limited by lack of proper marketing channels. As a result, losses and wastage are incurred. Interventions in terms of proper handling, value-addition and preservation technologies are required. This does not only increase the shelf-life of these products, but also increases income generation for the small and medium livestock keeper. This unit addresses how livestock products, and by-products from cattle, pigs, poultry and rabbit can be preserved. The pictures below show fresh and preserved livestock products with some contrast of how some of these products can get spoilt.

6.1: Importance of preservation of livestock products

 Activity 6.1: Observing destroyed and fresh products 

Materials required

• Destroyed and fresh livestock products such as meat, milk, skin, ice cream, cheese and blood

 • Hand gloves

 • Scalpels 

Use the products exhibited to carry out the following activities:

 (i) Observe the characteristics of the destroyed livestock products and fresh livestock products displayed. (ii) Compare the characteristics of the destroyed livestock products with fresh livestock products displayed. (iii) Record your observations in table 6.1 below and discuss your findings.

(iv) Using your experience, find out the importance of preserving livestock products.

 Note: Do not taste any of the materials provided. 

(v) Present your findings to the class. 

(vi) Take the teacher’s summary notes.

Preservation is the process of preventing deterioration of products. Livestock products such as meat, milk and eggs form a major component of the economy of any nation as source of food. Most livestock products, like other agricultural products, are highly perishable, meaning that they easily go bad. They should, therefore, be kept properly in order to maintain their quality

The preservation of livestock products is important for the following reasons: 

(i) To increase their shelf-life Shelf-life is the period of time that a product remains in good condition under storage. 

(ii) To lower the activity of micro-organisms and, therefore, prevent rotting of products. 

(iii) To add value to the products – Processed livestock products fetch higher prices in the market hence high profits. 

(iv) To add flavour to the food – Processed livestock products improve in smell, taste, appearance, colour and texture.

General methods of preserving livestock products 

The following are the general methods of preserving livestock products:

(a) Drying 

This is a method of preservation where water is removed through evaporation. The evaporation may be done through sun drying or by use of an air current (air drying). Drying inhibits the growth of micro-organisms that cause spoilage of the products. It is one of the oldest methods of preservation. It is used for preserving meat, fish, hides and skin.

(b) Salting

 This is a method of preservation where dry table salt is applied on the surface of the product. The salt removes water from the product by osmosis. Salting inhibits the growth of pathogenic organisms such as bacteria and fungi as they get dehydrated by the high salty environment and die or become temporarily inactivated. It is one of the oldest method of preservation and is used for the preservation of meat, fish, hides and skin.

(c) Smoking 

This is a method of preservation where the product is exposed to smoke from a burning material usually wood. This method is usually applied on food products. Besides preserving the food, smoking also adds flavour to it. This method is used on meat, fish and cheese.

 (d) Cooling or refrigeration

 Cooling is a method of preservation where ambient temperatures are lowered to levels where microbial activities are greatly reduced. This may be done through refrigeration or use of any other coolant such as water to conduct heat away from the product. This method is used for preserving food substances such as meat, milk and fish.

(e) Heat treatment 

This is the preservation of livestock products by the application of heat to the product. It includes heat treatment measures as boiling of food, milk (pasteurisation), cooking and wasting of meat. Very high temperatures destroy micro-organisms that cause food spoilage.

(f) Freezing 

This is a method of preservation where the growth of micro-organisms is slowed down by very low temperatures of about -23°C. The frozen water is also not available to the micro-organisms and this further reduces the activity of micro-organisms.

(g) Canning 

In this method of preservation, food is cooked and sealed in a sterile container. It is then boiled to kill any remaining bacteria. This method is used for preserving meat and milk products.

Fermentation 

The carbohydrates in the food are converted into alcohol and organic acids, for example, lactic acid. Lactic acid prevents further action by micro-organisms thus preserving the food. Fermentation is brought about by beneficial micro-organisms under anaerobic conditions. This is an old method of food preservation. It is used to preserve meat and milk products.

(i) Sugaring 

This is a method of preserving meat where sugar is applied in form of honey, syrup and solids. The sugar then absorbs water in the products through osmosis. This lowers the activity of the micro-organisms which destroys the product. Sugar also promotes the growth of favourable micro-organisms such as lactobacillus which produce lactic acid. Lactic acid prevents growth of unwanted micro-organisms.

(j) Jellying 

This is a method of preservation where the material to be preserved is kept in a substance that solidifies to form a gel, for example, gelatin. It is used in the preservation of meat.

(k) Use of chemicals 

This is the use of chemicals to preserve livestock products. It is commonly used in the preservation of food materials such as meat, hides and skin. Common chemicals used in food preservation include sodiumbenzoate, sodium nitrite and sulphur (IV) oxide. These chemicals inhibit the growth of micro-organisms that spoil food.

(l) Pickling 

This is the use of an edible anti-microbial liquid to preserve food. Examples of such liquids include brine (strong salt solution), vinegar and vegetable oils such as olive. This method is used in storing meat and eggs.

(m) Vacuum packing 

This is the storing of food in a vacuum environment usually in an air-tight bag or bottle. The vacuum condition deprives micro-organism of oxygen thus reducing their activity. This method is used for preserving cheese.

6.2 Preservation of cattle products and by-products 

Activity 6.2: A field trip to livestock processing industries and a dairy to observe processed products Materials required

• Note book 

• Questionnaire 

• Pen 

(i) Visit a livestock product processing industry and a dairy to observe different operations carried out to preserve livestock products in the industry and the dairy. 

(ii) Video case to identify different methods of preserving cattle products:

Materials required 

• Video tape or video showing cattle products preservation methods. 

• Screen/video player or television 

Watch a video showing different methods of preserving cattle products and byproducts then carry out the following activities:

 (i) Identify the different methods used to preserve different cattle products and byproducts.

 (ii) Discuss the methods of preservation observed and make a report. 

(iii) Present your findings to the class. 

(iv) Take teacher’s summary notes. 

Products obtained from cattle include, meat, milk, ice cream, cheese and yoghurt, while the by-products include hide, tallow, gelatin, leather, blood, horns and bones. Most of these products are perishable and require preservation.

Preservation of cattle products

 (a) Meat

After dressing of the carcass, meat is cut into thin strips or flat pieces while fresh and then preserved as follows:

 (i) Drying – The strips of meat are sun-dried or open air dried to reduce moisture content which discourages growth of bacteria hence spoilage. The disadvantage of this method is contamination of meat with dust and insects.

(ii) Curing – The dried meat strips may be cured through salting, sugaring and smoking. Curing removes excess water from the meat reducing microbial spoilage. Sugaring is done where sweet meat products are required. Smoking removes water and adds flavour to the meat.

(iii) Boiling or cooking – Cured meat can be cooked or boiled before consumption. Raw meat is cooked or boiled and packed in sterile containers. The containers are further sterilised.

(iv) Freezing and refrigeration – Pieces of raw meat or raw meat strips are put in a freezer where temperatures are low to inactivate the activities of micro-organisms.

(v) Fermentation – The meat to be preserved is first crushed to form minced meat and mixed with spices, vinegar and wine and packed in nature edible cellulose casing and hung to dry

(b) Raw milk 

Milk is a highly perishable animal product. Raw milk is preserved through the following methods:

(i) Pasteurisation

 Involves heating milk to a temperature of 50°C – 60°C and then cooling rapidly. The pasteurised milk is then packed in sterile containers such as tetra pack and bottles.

(ii) Use of chemicals 

Chemicals such as hydrogen peroxide, sodium thiocynate and sodium bicarbonate are used to preserve milk. They inhibit the growth of anaerobic bacteria thus increasing the shelf-life of milk.

(iii) Cooling and freezing 

Raw milk is subjected to low temperature to minimise the activity of microorganisms and their multiplication. This is a common method of milk preservation of raw milk and homogenised milk at the shop shelves.

(iv) Boiling 

This is the most common method of preserving raw milk. When milk is heated at 100°C most of the bacteria which cause milk spoilage are killed. This increases the keeping quality and shelf-life of milk. It is a common method of preserving milk at home.

(v) Ultra heat treatment 

This milk is heated at a temperature between 130°C and 135°C for a second and immediately packed and cooled. The milk quality is maintained. This temperature also kills micro-organisms such as Bacillus tuberculosis and Brucella arbotus found in fresh milk.

(c) Ice cream 

Newly churned ice cream should be chilled immediately and stored in a freezer as far back as possible. This makes it remain firm and keeps the ice crystals small. It should be stored in an airtight container. It should only last for a week or two to keep its flavours and texture.

(d) Cheese 

In the preservation of cheese, the following is important: 

(i) It should not be wrapped tightly to allow the pungent ammonia smell to come out. 

(ii) Cheese should be wrapped in cheese bags or cheese paper which is porous and allow cheese to breath. If cheese is wrapped in plastic bag, it will take the flavour of the plastics.

 (iii) The paper should always be replaced after unwrapping. Softer cheese should be kept in brine solution. The solution should be replaced every few days to prevent contamination. 

(iv) Cheese cuts should be rubbed in a light coat of olive, canola or vegetable oil and stored in air tight container to prevent molds. Cheese is also preserved through refrigeration.

(e) Yoghurt 

Yoghurt is preserved through refrigeration. Rapid cooling of yoghurt inactivates further bacteria, action to stabilise lactic acid. Yoghurt will keep for about 10–21 days if held in a refrigerator at 4.4°C or lower. Yoghurt may also be salted and dried to preserve it.

Preservation of cattle by-products

 Cattle by-products include: hide, tallow, gelatin, leather, blood, horns and bones.

Hide

 The hide is preserved through curing and drying up. The table below shows different cattle by-products. Discuss it in groups and then complete the table by filling in the methods used to preserve each by-products.

(i) Curing 

Curing of the hide is done by application of salt, which is referred to as salting. Salting is done in the following ways: 

• Wet salting The fleshed and washed hide are left in a cool room for several hours so that they can lose heat. They are then spread with the flesh side up on a wooden platform which is about 10 cm high. The flesh side is then covered with layers of salt. Salt absorbs moisture from the hide and, therefore, decomposition cannot occur. The salt is then shaken off from the hide. 

• Brining The washed hide is soaked in a drum containing brine overnight. After which is air dried or sun dried. 

• Dry salting A layer of salt is applied on the flesh side of the hide after flaying. Salt prevents decomposition which may occur during the first few days of hide curing. It is then suspended on a frame to dry. 

• Quick drying A lot of salt is rubbed vigorously on the flesh side of the hide, immediately after flaying. The salt is applied at the rate of 2 kg per hide. The hide is then folded and rolled like a blanket. It is placed under a heavy weight for about two days. It is then unfolded and suspended by a frame to dry.

(ii) Drying 

Hides are dried by suspending them in a frame in such a way that there is free air circulation from all the sides. The frames measure 2.7 m × 3.1 m for large hides and 2.7 m × 2.4 m for the smaller hides. The distance between the frames should not be less than 23 cm in order to allow free circulation of air and permit the operator to pass between them. The hides are laced on the frames with sisal strings, bark or skin straps. Avoid using the wire for lacing because it is not elastic and can tear the hole out. It may also rust leading to formation of stains during tanning.

6.3 Preservation of pig products and by-products

 Activity 6.3: Finding out the methods of preserving pig products and by-products 

Materials required 

• Textbooks 

• Dictionaries 

• Internet 

Use the references provided to:

 (i) Find out the methods of pig products and by-products preservation.

(ii) Discuss and record your findings. 

(iii) Present your findings to the class. 

(iv) Take teacher’s summary notes.

 Pig products include; meat (pork and bacon) and pig fat known as lard, while pig byproducts include suede and gelatin.

Preservation of pig products

 (i) Preservation of Pork

After dressing the pig carcass, the meat is cut into slabs of between 4 and 6 inches. The meat is then cured by applying salt and sugar mixture. The pieces of meat are well coated with the mixture. The meat is then kept in a crock or jar which is covered tightly with cheese cloth. The containers are then kept in a freezing condition of about 3.0 – 3.5°C for at least a month. The pork may also be preserved by brining. This is done by packing the pieces of meat in a sterilised crock or jar and covering with a brine made up of water, salt and brown sugar. Ensure that the salt and sugar mixture is properly dissolved in water. Cover the container and store for a week at about 3°C.

(ii) Preservation of Bacon 

Bacon is meat obtained from a pig. The following methods are used to preserve bacon:

 (a) Salting: Either in brine or in dry salt, cold drying, boiling and smoking. 

(i) Salting involves putting bacon in either dry salt or brine which dehydrate the meat killing bacteria. This process involves cleaning the raw meat then covering it in salt for about one month while it is gradually pressed. Pressing is done to remove all the fluids and blood. Spices and herbs are also added.

(ii) Smoking involves cutting small pieces of bacon which are then placed over a smoky flame. This kills bacteria and also improves the quality of bacon. 

(iii) Cold drying involves salting then hanging the bacon in cold wind for approximately one month. Cold drying dehydrates the meat and kills micro-organisms which causes spoilage. 

(iv) Boiling involves heating of pork in brine or lard to kill micro-organisms using high temperature.

(b) Use of chemicals: Nitrates are added to ground bacon. These chemicals kill micro-organisms and provide a hostile environment which prevents the growth and multiplication of bacteria. Nitrates also make the meat have a distinctive pink or red tinge and imparts a flavour. 

(c) Fermentation: The bacon is first crushed to form minced meat. Bacon is mixed with a variety of ingredients which include garlic, salt, spices, vinegar and wine. The meat is allowed to ferment for one day. Then is packed in a natural edible cellulose casing and hung to dry.

(iii) Preservation of Lard 

Lard is fat derived from pig meat. It is preserved through heating and cooling. The fat is chopped into small pieces and then heated until melting takes place. The meat particles are removed through decanting. The lard is put in bottles while still hot and sealed. It is allowed to cool.

Preservation of pig by-products 

Pig by-products include suede and gelatin. For each by-product listed in the table below, fill in the methods of preservation.

6.4 Preservation of poultry products 

Activity 6.4: Finding out the methods of preserving poultry products and by-products

Working in groups:

 (i) Find out how poultry products and by-products are preserved from dictionaries, textbooks and internet. (ii) Record and discuss your findings. 

(iii) Present your findings to the class. 

(iv) Take teacher’s summary notes.

 Poultry products include meat and eggs. If the meat is from the domestic fowl(chicken) it is known as chicken. Discuss in groups and indicate the methods of preserving poultry products by filling in the table below:

6.5 Preservation of rabbit products 

Activity 6.5: Finding out how rabbit products and by-products are preserved 

Materials required

• Textbooks 

• Dictionaries 

• Internet 

Use the references provided to:

 (i) Find out the methods of preserving rabbit products and by-products from text books, dictionaries and internet.

 (ii) Discuss and record your findings.

(iii) Present your findings to the class. 

(iv) Take teacher’s summary notes. 

Rabbit products include meat and fur. Discuss the methods of preserving rabbit products and indicate by filling in the table below:

Group Activity 

Working in groups, carry out the following activities:

(i) Group I – Discuss different methods of preserving cattle products. 

Group II – Discuss different methods of preserving pig products. 

Group III – Discuss different methods of preserving poultry products.

 Group IV – Discuss different methods of preserving rabbit products.

 (ii) Make a report on your findings.

 (iii) Present your findings to the class. 

(iv) Take teacher’s summary notes.

Unit Summary 

Preservation of livestock products is a very important and necessary practice in livestock production. Most of the livestock products get spoilt by micro-organisms and oxidation after they are obtained from the livestock. This is due to lack of proper preservation measures. Preservation measures aim at reducing the activities of microorganisms and preventing oxidation of products. Preservation measures taken either kill the micro-organisms or inhibit their activities. This may be achieved through the following measures:

 (i) Raising the temperatures to high levels which destroy the micro-organisms through cooking, boiling or roasting the products.

 (ii) Lowering the temperature levels that inactivates the micro-organisms through cooling, refrigeration and freezing.

(iii) Preventing micro-organisms from getting water for survival, through drying, freezing, salting, sugaring, smoking and use of honey. 

(iv) Preventing micro-organisms from getting oxygen by use of honey, vacuum packing, freezing, smoking and refrigeration. 

(v) Dehydrating the micro-organisms by salting and sugaring.

Key Terms

 1. Preservation – Process of preventing deterioration of products. 

 2. Perishable – Gets destroyed easily through decomposition.

 3. Shelf-life – Period of time that a product can remain in good condition under storage.

 4. Micro-organisms – Organisms that are too small to be observed through the naked eyes.

 5. Pathogens – Organisms that cause diseases.

 6. Salting – Application of dry salt on the surface of a product to preserve it.

 7. Smoking – Exposing a product to smoke in order to preserve it. 

 8. Drying – Removal of water from a substance/product through evaporation. 

 9. Refrigeration – Removal of heat from a substance under controlled conditions. 

10. Cooling – Lowering the temperatures of substance. 

11. Freezing – Lowering the temperatures of a substance to a point where water solidifies. 

12. Canning – Preservation of cooked food in sealed containers.

 13. Anaerobic respiration – Breakdown of carbohydrates in the absence of oxygen. 

14. Fermentation – Preservation by allowing the sugars in a food substance to undergo anaerobic respiration where the acids or alcohol produced protects the food from further spoilage by micro-organisms. 

15. Sugaring – The application of sugar to the surface of a substance to withdraw water by osmosis. 

16. Jellying – Preservation of a food material in a substance that later on solidifies to form a gel. 

17. Pickling – Preservation of food in an anti-microbial edible liquid, for example, olive oil.

 18. Vacuum packing – Preservation of food in an airtight bag or bottle. 

19. Tallow – Fats from cattle meat. 20. Lard – Fats from pig meat.

20. Lard – Fats from pig meat. 200 

21. Gelatin – A translucent flavourless food substance derived from animal products. 

22. Pork – Fresh pig meat.

 23. Bacon – Processed pig meat that has been preserved through salting or brining. 

24. Suede – Leather from pig skin. 

25. Beef – Cattle meat.

Revision Questions

1. What is preservation? 

2. State five importance of preserving livestock product. 

3. State five indicatorsthat help to determine whether a product isfresh or destroyed. 

4. The following are various livestock products and by-products. Study them carefully and then group them into products and by-products. Hide, raw milk, eggs, fur, tallow, yoghurt, pork and suede. 

5. Explain one factor which is common in the following methods of preserving livestock products; salting, sugaring, drying and freezing. 

6. Describe five methods of preserving cattle meat.

 7. Explain the following methods of preserving livestock products:

 (i) Fermentation (ii) Use of honey

 (iii) Pickling 

8. Carry out the preservation of hides using frame drying method.

 9. The photograph below illustrates a method of preserving meat. Study it and identify the method of preservation.

10. Name two rabbit products. 

11. Give two advantages of smoking as a method of preservation. 

12. The following are methods of preserving livestock products.

            (i) Canning 

            (ii) Salting

            (iii) Pickling 

            (iv) Cooling 

Which of the following sets are methods of preserving eggs? 

A. (i) and (ii) 

B. (ii) and (iii) 

C. (iii) and (iv) 

D. (i) and (iv)