ABSTRACT 

This project work studied the occurrence of bacteria in packaged fruit juices and their control with lactic acid bacteria isolated from fermented African oil bean seeds (pentaclethra microphylla) packaged fruit juices Ribena and Happy Hour were selected randomly from five market locations in Orieugba, Umuahia city centre, Ubani central market, Ahiaeke daily market and Umudike Mammy markets respectively and studied. Four bacteria species were isolated and identified from the fruit juices with varying levels of occurrences including Staphylococcus species (60%), Escherichia coli (12.5%), Bacillus species (40%) and Pseudomonas species (30%). Also, two lactic acid bacteria, Lactobacillus plantarum and Lactobacillus casei were isolated from randomly selected Ugba samples with occurrences of 100% and 66.7% respectively. Crude extracts from both LAB isolates demonstrated antibacterial activity against the packaged fruit isolates in which the inhibition zone of L. plantarum was in the range of 8.67mm (Bacillus species) to 14.67mm (E. coli) while that of L. casei ranged between 8.33mm (Bacillus) and 14.67mm (E. coli). The two test LAB inhibited Staphylococcus minimally with inhibition zone of 8.67mm and 10.33mm for the L. casei and L. plantarum respectively whereas their inhibition zone against Pseudomonas species were 11.67mm each for the LAB isolate. The overall antimicrobial activities of the LAB isolates were lower than the activity of standard antibiotic which caused inhibition in the range of 18.00mm (Pseudomonas species) to 24.67mm (E. coli). The relative potencies of the LAB isolate compared with the reference standard antibiotics were in the range of 46.43% (Bacillus species) to 64.83% (Pseudomonas species) for L. plantarum and 41.94% (Staphylococcus species) to 64.83% (Pseudomonas species) for L. casei. Both LAB isolates were deemed to have potentials for use in the control of the packaged juice bacteria isolates.      

TABLE OF CONTENTS 

Title page i

Certification ii

Dedication iii

Acknowledgements iv

Table of contents v

List of tables vii

List of figures viii

Abstract ix

CHAPTER ONE

1.0 Introduction 1

1.1 Aim and Objectives 2

CHAPTER TWO 

2.0 Literature Review 4

2.1 Fruit juice 4

2.2 Health benefits of fruit juices 4

2.3 Heat Resistant Fungi Spoilage of Pasteurized fruit juices 6

2.4 Preservation of fruit juices 6

2.5 Factors affecting shelf life of juices 7

2.6 Deterioration of fruit juices by microorganisms 7

2.7 Microorganisms Associated with Spoilage in Fruits and Juices 8

2.7.1 E. coli (Escherichia coli) 10

2.7.2 Salmonella species 10

2.7.3 Staphylococcus aureus 11

2.7.4 Pseudomonas species 11

2.7.5 Serratia species 11

2.7.6 Yeasts 12

2.7.7 Molds 13

2.7.8 Bacteria 14

2.7.9 Lactic Acid Bacteria 15

2.7.10 Acetic acid bacteria 16

2.7.11 Spore formers 16

2.8 Ugba and Microorganisms involved in the fermentation 16

2.9 Changes that occur during fermentation 19

2.10 Optimization of Ugba Fermentation 21

2.11 Microbiological safety of Ugba 22

CHAPTER THREE

3.0 Materials and Methods 24

3.1 Source of Material 24

3.2 Microbial Analysis of Fruit Juices (Screening for bacteria in fruit juices) 24

3.3 Media Preparation 25

3.4 Isolation of bacteria from fruit juices 26

3.4.1 Characterization of Bacteria Isolates 24

3.4.2 Identification of Isolates 29

3.5 Isolation of LAB from Ugba 29

3.6 Antibacteria activity of LAB isolates against fruit juice bacteria isolates 29

CHAPTER FOUR

4.0 Results 30

CHAPTER FIVE

5.0 Discussion, Conclusion and Recommendations 38 

5.1 DISCUSSION 38

5.2 Conclusion 42

5.3 Recommendations 42

References 43

Appendix 48