ABSTRACT

Sorghum is the fifth most important cereal after rice, wheat, maize and barley. Like every other plant, sorghum is attacked by microorganisms. Fungal species such as Aspergillus parasiticus and Aspergillus flavus grow on sorghum and consequently produce a mycotoxin known as aflatoxin. Aflatoxin is a toxic metabolite which causes acute illnesses such as liver damage ad cancer, even death when consumed in large quantity. Aspergillus parasiticus and Aspergillus flavus were isolated from sorghum seeds by culturing on Potato Dextrose Agar and the level of aflatoxin content of the seeds determined using ELISA method. Sorghum treated with only water, water and salt and water, salt and heat dried had a total viable count of 1.8x101cfu/ml, 7x101cfu/ml and 8x101cfu/ml respectively. The total aflatoxin content of the samples were 2.80ppb, 2.70ppb and 2.35ppb respectively. In addition, the aflatoxin content of the untreated sample was 4.00ppb. The germinative energy of all treated samples were 100%, 80% and 30% respectively.  Hence, producers should adopt treatment of raw sorghum with salt and heat-drying it in the HACCP steps to ensuring production of food safe for consumption. However, for production processes that require germination of the grains, the grains should first be germinated before heat-drying since it reduces the seeds germinative energy. 

TABLE OF CONTENTS

Title Page i

Certification ii

Dedication iii

Acknowledgement iv

Table of Contents v

Abstract  x

Chapter one: Introduction 1

1.1. Overview 1

1.2. Sorghum and Fungi 2

1.3. Contamination conditions 3

1.4. Aims and Objectives 4

Chapter two: Literature Review 5

2.1. Aflatoxins 5

2.2. Toxicology 10

2.3. Pathology 12

2.3.1. Aflatoxicosis 12

2.3.2. Aflatoxicosis and child health in Nigeria 12

2.3.3. Aflatoxicosis and hepatic deaseas 13

2.3.4. Other effects of aflatoxicosis 14

2.4. Diagnosis 15

2.5. Prevention and control of exposure to aflatoxins 15

2.5.1. Education 15

2.5.2. Processing 16

2.5.3. Use of Antioxidants and Minerals 16

2.5.4. Aflatoxins Monitoring 16

Chapter Three: Materials and Methods 18

3.1. Isolation of Aspergillus flavus and Aspergillus parasiticus 18

3.1.1. Materials and instruments used 18

3.1.2. Sample preparation 19

3.1.3. Medium preparation 20

3.1.4. Plating the seeds 20

3.1.5. Total viable count on assay. 20

3.1.6. Counting of the colonies 21

3.1.7. Germinative energy 21

3.2. Estimation of aflatoxins 22

3.2.1. Materials and instruments used 22

3.2.2. Sample preparation 23

3.2.3. Aflatoxn detection 24

Chapter four: Result 25

4.1. Total viable count (TVC) from the assay of all treated sample. 26

4.2. Germinative energy of treated samples. 27

4.3. Microorganisms isolated from all the samples 28

4.4. The Aflatoxin content of all samples 29

Chapter five: Discussion, Recommendations and Conclusion 30

5.1. Discussion 30

5.2. Recommendations 31

5.3. Conclusion 31

References

LIST OF TABLES

Table Title Page

2.1 Some Aflatoxins and Sources. 7

2.2 Chemical and physical properties of some 

aflatoxins 8

 4.1 Total viable count (TVC) from the assay 

 of all treated sample. 26

  4.2 Germinative energy of treated samples. 27

  4.3  Microorganisms isolated from all the samples 28

  4.4 The Aflatoxin content of all the samples 29

LIST OF FIGURES

Figure Title Page

 2.1. Structure of aflatoxins B1, B2, G1, and G2 9

 2.2. Pathways and consequences for Aflatoxin in 

animal metabolism 11