Effect of the Lactoperoxidase System on the Activity of Mesophilic Cheese Starter Cultures in Goat Milk

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Literature Review 

Goats as important milk producers in the tropics

Since the dawn of civilization, man has used the milk of different domestic animals as food. However, cattle, buffaloes, goats, sheep and camels are the major livestock species which provide milk in the tropics. Among these species, cows are the main milk producers in the tropics (Chamberlain, 1989); however, the goat by virtue of its origin, distribution and unique anatomy and physiology, and behavioural characteristics represents an under-utilised resource that at the same time has great potential for increasing milk production in the tropics (Knights & Garcia, 1997).
The suitability of the goat for milk production in the tropics is related to many factors:
their small size relative to the cow which makes them better suited to the needs and capabilities of smallholders; their fast reproductive rate and short generation interval; their disease tolerance and adaptation to both hot and dry tropical areas; their adaptability to a wide range of feeds; their efficiency of converting high fibre roughages to human food (Devendra, 1978; Devendra, 1981; Matthewman, 1985; DeVries, 1988; Knights & Garcia, 1997). Moreover, goats have also been claimed to have greater milk production efficiency in terms of live weight, in view of their lower maintenance needs in comparison to cows and buffaloes when reared under the same conditions (Devendra, 1975; Devendra, 1978; Knights & Garcia, 1997).
Goat milk is produced in many parts of the world in particular in Southeast Asia mainly in India and Bangladesh; in the Near East countries such as Iraq, Cyprus, Turkey, Syria, Iran; in African countries such as Libya, Morocco, Sudan, Niger and Somalia; in European countries such as Greece, Spain and France (Devendra, 1975, 1980, 1981). The contribution of goat milk to overall milk production in some individual countries could be considered significant, reaching levels of 44 % in Mali, 29 % in Somalia, 24 % in Iran and 16 % in Sudan (Knights & Garcia, 1997), In the Caribbean, for example, Haiti and Bahamas, the contribution of goats to milk production is approximately 50 % of the total milk produced (Matthewman, 1985). However, it should be noted that these are only estimates and since because ofdifficulty of measuring yield and lack offormal marketing for goat milk, it is difficult to get the exact figures. In each of these countries, goat milk is used for diversified purposes. For instance, in the USA, which has plenty of cow milk, goat milk finds a market because of its alleged superiority in nutritional quality or reported value as a source of milk for individuals suffering from allergies to the proteins of cow milk (Jenness, 1980). In brief, goat milk is used by necessity in some countries, by choice in others and by a combination ofthe two in still others.

The dairy goat industry in South Africa 

The dairy industry of South Africa is regarded as a mixture of ‘several worlds’ which is ‘developed’ on the one hand, with large milk producers using modern production methods, processing facilities and supermarket distribution, and ‘developing’ on the other hand, with many small milk producers using relatively primitive production and distribution methods (Hermann, 1996). Du Toit (1997) on his report on small-scale milk production and processing in South Africa indicated that thousands of people are entering the field of agriculture as small farmers. He further pointed out that these farmers would contribute considerably towards achieving household food security in the country. Most of these reports regarding the dairy industry of South Africa focused mainly on cow milk production. There is limited information on goats and goat milk production in South Africa. However, currently there is a growing interest in the dairy goat sector. More and more farmers and small-stock owners are considering the milking of goats as a possible farming alternative. The national programme on commercialisation of Indigenous goats launched by the Animal Nutrition and Products Institute of the Agricultural Research Council emphasizes the importance of this sector (USAID & ARC, 1998b).

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Table of Contents

  • DECLARATION
  • DEDICATION
  • ACKNOWLEDGEMENTS
  • ABSTRACT
  • LIST OF TABLES
  • LIST OF FIGlTRES

CHAPTER 1:  General Introduction and Literature Review
1.1. General Introduction
1.2. Literature Review
1.2.1. Goats as important milk producers in the tropics
1.2.2. The dairy goat industry in South Africa
1.2.2.1. Dairy goat breeds in South Africa
1.2.2.2. Goat milk and milk products in South Africa
1.2.3. Nutritional advantages of goat milk
1.2.4. Microbiological and public health aspects ofgoat milk
1.2.5. Goat cheese production
1.2.6. Constraints to goat milk production
1.2.7. Milk collection and preservation
1.2.8. The lactoperoxidase system
1.2.8.1. Components ofthe lactoperoxidase system
1.2.8.1.1. Lactoperoxidase
1.2.8.1.1.1. Physico-chemical properties oflactoperoxidase
1.2.8.1.1.2. Concentration oflactoperoxidase in milk
1.2.8.1.2. The thiocyanate ion
1.2.9.1. Antibacterial effect of the lactoperoxidase system
1.2.9.2. Antifungal effect of the lactoperoxidase system
1.2.9.3. Antiviral effect of the lactoperoxidase system
1.2.10. Effect ofthe lactoperoxidase system in the preservation of raw  milk
1.2.11. Effect ofthe lactoperoxidase system on cheese starter cultures
1.2.12. Effect ofthe lactoperoxidase system on the manufacture of fermented milk products
1.2.13. Potential applications of the lactoperoxidase system
1.2.14. Objectives
1.2.15. Hypothesis

Antibacterial Activity of the Lactoperoxidase System Against  Food-borne Pathogens in Saanen and South African Indigenous

CHAPTER 2: Goat Milk

1.1. General Introduction
1.2. Literature Review
2.1 Introduction
2.2Materials and methods
2.2.2 Maintenance of test organisms
2.2.3. Preparation ofbacterial suspensions
2.2.4. Inoculation ofmilk samples with pathogens
2.2.5. Activation ofthe lactoperoxidase system
2.2.6.  Enumeration ofpathogens
2.2.7. Quantification and confirmation of viable bacteria after treatment
2.2.8. Thiocyanate content of the milk samples
2.2.9. Lactoperoxidase activity of the milk samples
2.3. Results
2.3.1. Thiocyanate content and lactoperoxidase activity
2.3.2. Effect ofthe lactoperoxidase system on the growth ofEscherichia coli
2.3.3. Effect ofthe lactoperoxidase system on the growth ofStaphylococcus aureus
2.3.4. Effect of the lactoperoxidase system on the growth ofListeria monocytogenes
2.3.5. Effect ofthe lactoperoxidase system on the growth ofBrucella melitensis61
2.3.6Effect of the lactoperoxidase system on the growth ofMycobacteriu paratuberculosis
2.4. Discussion
2.5.Conclusions
2.6. References

CHAPTER 3:  Effect of the Lactoperoxidase System on the Activity of
Mesophilic Cheese Starter Cultures in Goat Milk
3.1. Introduction
3.2. Materials and methods
3.2.1. Starter cultures
3.2.2. Source of milk sample
3.2.3. Treatment of the milk samples
3.2.4. Growth and activity tests of the starter cultures
3.2.5. Determination of chemical composition
3.2.6. Statistical analysis of the data
3.3. Results and discussion
3.3.1. Mixed strain starter cultures
3.3.2. Single strain starter cultures
3.4. Conclusions
3.5. References

CHAPTER 4:  Quality Aspects of Gouda Cheese Made from Goat Milk Preserved by the Lactoperoxidase System
4.1. Introduction
4.2. Materials and methods
4.2.1. Source and treatment ofmilk samples
4.2.2. Cheesemaking
4.2.3. Sampling of cheese
4.2.4. Rennet clotting time
4.2.5. Gross chemical composition
4.2.6. Measurement ofnitrogen fractions
4.2.7. Free fatty acid (FFA) analysis
4.2.8. Microbiological analyses
4.2.9. Sensory analysis
4.2.10. Statistical analysis
4.3. Results and discussion
4.3.1. The composition of Saanen and South African Indigenous goat milk
4.3.2. Effect ofthe lactoperoxidase system on the clotting time and
microbiological properties ofthe Saanen goat milk used for cheesemaking
4.3.4. Effect of the lactoperoxidase system on the yield and gross chemical composition ofGouda cheese
4.3.5. Effect ofthe lactoperoxidase system on the level ofproteolysis and lipolysis in Gouda cheese
4.3.6. Effect of the lactoperoxidase system on the sensory properties of Gouda  cheese
4.4. Conclusions
4.5. References

CHAPTER 5 : General Discussion, Conclusions and Recommendations
5.1. General Discussion
5.2. Conclusions and Recommendations
6. References
7. Publications

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