University of Khartoum Graduate Collage Medical & Health Studies Board Fungal Contamination in Cheese at Khartoum North Markets By Hawyda Abdel Azim Abdel Alatif Mohammed B.Sc. U.of Shendi (2004) A thesis submitted in partial fulfillment for the requirements of the degree of master of Public and Environmental health (Food hygiene and safety) Supervisor: Dr/ Elrasheed A.Ali B.Sc.Vet.M.Sc.Ph.D Uof K 2010 ` Didicailion To My Father and Mother To My beloved husband and Sondos To My brother and sisters i ` Acknowledgement All thanks to my supervisor Dr.Alrasheed A.Ali for his supervision and valuable guidance. I should also acknowledge with thanks the valuable help from the Staff of the department of food Hygiene and safety ii Table of content Dedication........................................................................................................................ I Acknowledgment.............................................................................................................. II Table of contents................................................................................................................. III Abbreviations........................................................................................................................VI Abstract English......................................................................................................................VII Abstract Arabic ......................................................................................................................IX Chapter One 1.1. Introduction..................................................................................................................1 1.1.1. Significance of study................................................................................................1 1.1.2. Objective...................................................................................................................2 1.2. Literature review...........................................................................................................3 1.2.1. Etymology.................................................................................................................4 1.2.2. History……………………………………………………………………………..4 1.2.3. Types..........................................................................................................................5 1.2.4. Fresh whey and stretched curd cheeses......................................................................6 1.2.5. Classified by texture...................................................................................................7 1.2.6. Classified by content..................................................................................................8 1.2.7. Soft ripened and blue vein..........................................................................................8 1.2.8. Processed cheeses...................................................................................................... 9 1.2.9. Eating and cooking......................................................................................................9 1.2.10. Health and nutrition................................................................................................10 1.2.11. Mould......................................................................................................................11 1.2.12. Biology....................................................................................................................12 1.2.13. Categories of mould.........................................................................................................................13 1.2.14. Uses of mould..................................................................................................................................13 iii 1.2.15. Drug creation....................................................................................................................................14 1.2.16. Health effects...................................................................................................................................14 1.2.17. Toxic mould......................................................................................................................................15 1.2.18. Diseases transmitted by mould..........................................................................................................17 1.2.19. Benefits of mould.............................................................................................................................19 1.2.20. Mould in processes...........................................................................................................................20 Chapter two 2.1. Materials and methods...........................................................................................................................21 2.1.1. Samples.................................................................................................................................................21 2.1.1.2. Transport and keeping of collected samples.......................................................................................21 2.1.1.3.LaboratoryEquipment............................................................................................................................21 2.1.3. Examination of mould.............................................................................................................................22 2.1.4. Examination of yeast................................................................................................................................22 2.1.5. Identifiction of molud and yeast...............................................................................................................22 Chapter three 3. Result..............................................................................................................................................................24 Chapter Four 4.1. Discussion...............................................................................................................................................39 4.2. Conclusion................................................................................................................................................42 4.3. Recommendation.....................................................................................................................................43 4.4. Reference................................................................................................................................................44 iv List of table Chapter three Table3.1Minimum and maximum range of mould contamination in cheese compare with acceptable Sudanese Standers Metro logy Organization……………………………………………………………………………………..25 Table 3.2 Total viable counts of yeasts isolated from 100 samples of cheese collected from different retail sale in Khartoum North……………………………………………………………………………………................26 Table 3- 3Total viable count (T.V.C) of moulds isolated from 100 samples of cheese collected from different retail sale in Khartoum North………………………………………………………………………………………………29 List of figures Chapter three Figures (3.1) Slides culture of Aspergillus pink colony on sabouruad Dextrose Agar isolated From 100 samples of cheese……………………………………………………………………………………32 Figures (3.2) Slides culture of Aspergillus fumigats green and dark colony on sabouruad Dextrose Agar isolated from 100 samples of cheese …………………………………………………………………………………32 Figures (3.3)Slides culture of saccharomyces white colony on sabouruad Dextrose Agar isolated from 100 samples of cheese ………………………………………………………………………………………………….33 Figures (3.4) Slides culture of Debaryomayces stained dark on sabouruad Dextrose Agar isolated from 100 samples of cheese ………………………………………………………………………………………………….33 Figures (3.5) Slides culture of Debaryomayces white colony on sabouruad Dextrose Agar isolated from 100 samples of cheese ……………………………………………………………………………………………………34 Figures (3.6) Slides culture of Aspergillus niger black colony on sabouruad Dextrose Agar isolated from 100 samples of cheese……………………………………………………………………………………………………34 Figures (3.7) Slides culture of Rhizopus dark pink on sabouruad Dextrose Agar isolated from 100 samples of cheese …………………………………………………………………………………………………………….35 Figures (3.8) Slides culture of Aspergillus fumigats green and dark colony on sabouruad Dextrose Agar isolated from 100 samples of cheese……………………………………………………………………………………..35 Figures (3.9) Slides culture of Debaryomayces stained dark on sabouruad Dextrose Agar isolated from 100 samples of cheese………………………………………………………………………………………………………36 Figures (3.10) Slides culture of saccharomyces white colony on sabouruad Dextrose Agar isolated from 100 samples of cheese ………………………………………………………………………………………………36 v Abbreviations pH Hydrogen ion concentration USA United States of America CFU|g Colony forming unit per gram HIV: Hepatitis Immune Virus. G.M.P: Good Manufacturing Bract ice. HACCP: Hazard Analysis and Critical Control. NACL: Sodium Chloride. vi Abstract Back ground: - Yeasts and moulds present a hazardous health problem in food, allowing outgrowth of both spoilage and pathogenic bacteria. Moulds are capable of forming toxins and causing mycotoxicoses in man and animals are distributed all over the world. They grow, produce toxins and multiply on a wide variety of foods over wide ranges of pH, temperature and humidity. Design: - Descriptive, cross sectional study.