ABSTRACT

Ice-cream is a nutritionally enriched diary products consumed by all age groups most especially children particularly in summer as well as throughout the year. Its microbial quality has always been crucially important to the public health. The present study was constructed to assess the bacteriological quality of ice cream sold in Umuahia. A total of 14 samples were randomly purchased from the fast food joint, supermarket, school, market and street hawkers differentiated in 2 categories: industrially produced ice cream (IND1-IND7) and locally produced ice cream (LP1-LP7). The total heterotrophic count range from 3.0x10³-2.0x106 (cfu/g) with industrially variety (IND3-IND4) recording no bacterial growth and also some lowest count while locally produced ice-cream has the highest count. The total staphylococcus ranged from 1.0x10² (cfu/g) in the industrially produced variety (IND4) to 3.0x10³ (cfu/g) in the locally produced variety (LP5). For E. coli count, the range was from 1.0x10² (IND2)-2.0X105 (LP5) (cfu/g) in both industrially produced and locally produced. The Lactobacillus count range from 1.0x10² (LP1)-1.0X104 (LP4) (cf/g). Total isolates were eight bacteria (Staphylococcus aureus, Lactobacillus spp., Streptococcus spp., Proteus spp.,Escherichia coli, Klebsiellae and Pseudomonas aeroginosa). Lactobacillus has the highest incidence (7) with the percentage of 50% while Proteus spp, Klebsiella, Pseudomonas aeroginosa had the least incidence and percentage of (1) 7.1%, (2) 14.2% and (2) 14.2% respectively. The total heterotrophic count was further subjected to a t- test statistical analysis which showed no significant difference (p<0.05;) between comparing the bacteriological quality of locally produced ice cream and industrially produced ice cream fall into the same categories. Since in the bacteriological count of ice cream industrially produced, 2 out of 7 products show no bacteria growth which implies that if adequate preparation that is standard process are used it is possible for industrially produced ice cream to be safe to health and better than locally produced ice cream. The presence of pathogenic organism in the ice cream  sample should be viewed with concern by the consumes, producers, ice cream manufacturing industries and the government since food poisoning by Staphuyloccocus Aureus, Bacillus spp, is possible through consumption of contaminated ice cream.

TABLE OF CONTENTS

Title page              i

Certification                                        ii

Dedication iii

Acknowledgement iv

List of tables v

CHAPTER ONE

1.0 Introduction 1

1.1 Aims and objectives 4

CHAPTER TWO

2.0 Literature review 5

2.1 Location of microbes 6

2.2 Manufacture of ice-cream 7

2.3 Microorganisms in ice-cream 7

2.3.1 Bacteria 8

2.3.2 Mould 8

2.3.3 Yeast 8

2.4 Microbial community of ice-cream 8

2.5 Hygienic and microbial aspects 9

2.6 Major diseases transmitted through ice-cream 13

2.7 Microbiology of ice-cream 15

CHAPTER THREE

3.0 Materials and method 17

3.1 Study area 17

3.2 Experimental design 17

3.3 Sample collection 17

3.4 Sterilization of materials 18

3.5 Media 18

3.6 Preparation of serial dilution 19

3.7 Bacteriological examination 19

3.8 Characterisation and identification of bacteria isolates 20

3.9 Gram staining 20

3.9.1 Catalase test 21

3.9.2 Coagulase test 21

3.9.3 Oxidase test 21

3.9.4 Citrate test 22

3.9.5 Motility test 22

3.9.6 Indole test 22

3.9.7 Statistical analysis 23

CHAPTER FOUR

4.0 Results 24

CHAPTER FIVE

5.0 Discussion 33

5.1 Conclusion 36

5.2 Recommendation 37

References

Appendix