ABSTRACT

The microbiological quality of ready-to-eat food products sold in a federal medical center was assessed. A total of forty eight  food samples, including beans, fried rice, jollof rice and moi-moi were collected from two food vending sites which serves as the major ready to eat food vending centres in the hospital premises. A total of nine species of microorganisms including Bacillus spp, Escherichia coli, Klebsiella spp, Proteus spp, Staphylococcus aureus, Aspergillus niger, Aspergillus fumigatus, Penicillium spp and Mucor spp were isolated from the food samples. The mean total aerobic plate count, coliform count and fungal count from Site I range from 2.5 × 103 to 9.1 × 106 cfu/g, 3.2 × 103 to 3.4 × 104 cfu/g, and 6.0 × 102 to 7.3 × 104 cfu/g respectively. Site II had aerobic plate count, coliform count and fungal plate count ranging from 2.7 × 103 to 9.8 × 106, 5.2× 103 to 7.8 × 104 cfu/g, and 9.0 × 103 to 9.3 × 106 cfu/g respectively. Based on the specifications by International Commission for Microbiological Specification for Foods (ICMSF), the level of contaminations was within acceptable microbiological limits except for beans; this could be attributed to extensive handling, mixing and to the fact that it is consumed as raw food. It is recommended that a closer and stringent supervision of ready-to-eat foods sold in hospital areas should be carried out by relevant authorities to prevent possible outbreak food borne illness.

TABLE OF CONTENTS

Title page i

Certification ii

Dedication iii

Acknowledgements iv

Table of Contents v

List of Tables vii

Abstract viii

CHAPTER ONE: INTTRODUCTION 1

1.1      Types of food 2

1.1.1 Fast food 2

1.1.2 Junk food 3

1.1.3 Whole foods 3

1.1.4 Organic foods 4

1.2 Sources of food 4

1.3 Aims and objectives    5

CHAPTER TWO: LITERATURE REVIEW 6

2.1 Microbial contamination 6

2.2 Microbial food contamination 7

2.3 Mechanism of microbial food contamination 18

2.3.0 Pre-Harvest/Harvest Contamination of Food 19

2.3.1 Pre-harvest Factors 19

2.3.2 Harvest factors 21

2.3.4 Pre-Slaughter and Slaughter Contamination 21

2.4 Microbiological food contamination at post harvest/post-slaughter 23

2.4.1 Food processing/ food preparation factors 23

2.4.2 Distribution, marketing and storage factors 26

2.5 Food contamination mechanism in some selected foods 27

CHAPTER THREE: MATERIALS AND METHODS 30

3.1 Study area 30

3.2 Media used 30

3.3 Sterilization 30

3.4 Sample processing 31

3.5 Physicochemical analysis 31

3.6 Identification of bacteria 31

3.7 Gram staining 32

3.8 Catalase test 32

3.8.0 Coagulase Test 33

3.8.1 Citrate Test 33

3.8.2 Motility test 33

3.8.3 Urease test 33

3.8.4 Indole test 34

3.8.5 Triple Sugar Iron Test 34

3.8.6 Oxidase Test 34

3.9 Identification of fungal isolates 34

CHAPTER FOUR: RESULTS    35

CHAPTER FIVE: DISCUSSION, RECOMMENDATION AND CONCLUSION

5.1 Discussion    40

5.2 Recommendation 41

5.3 Conclusion 42

References 43