ABSTRACT

Salmonella is among the most important foodborne pathogens worldwide with fresh vegetables as major route of transmission to man. A total of 12 samples of carrot samples were analyzed for the presence of Salmonella species using standard plating techniques on Salmonella Shigella agar. Samples were cultured using selective isolation with prior enrichment method. Presumptive isolates were identified and characterized using conventional biochemical methods. These bacteria species were tested for their susceptibility to standard antibiotics by agar disk diffusion method. Mean bacterial load of the carrot samples was 7.47logcfu/g for samples obtained at Orieugba Market; 7.13logcfu/g at Isigate Market and 7.27logcfu/g for Ndioru market. Similarly, the coliform counts were 4.93logcfu/g, 2.83logcfu/g and 3.50logcfu/g for Orieugba Market, Isigate Market and Ndioru markets respectively. All Salmonella isolates (100%) were resistant to Augmentin. high resistance percentage was observed against nitrofurantoin (45.5%), cefuroxime (72.7%), cefotaxime (72.7%), for the Salmonella isolates. Eight out of the eleven (72.7%) Salmonella isolates in this study were susceptible to Gentamicin while 18.2% of the Salmonella isolates were resistant to ofloxacin. The emergence of high antimicrobial resistance among Salmonella isolates is alarming since these vegetables are commonly eaten raw and has obvious implications for public health because multidrug resistance limits the possible effectiveness of therapeutic treatments. This study provides data that support the potential transmission strains of Salmonella harboring resistance factors from vegetables and environmental sources to cause infections in humans.

TABLE OF CONTENTS

Title Page i

Certification ii

Dedication iii

Acknowledgements iv

Table of Contents v

Lists of Tables vii

Abstract viii

CHAPTER ONE

1.0 Introduction

1.1Aims and Objectives

CHAPTER TWO

2.1Literature Review

2.2Carrot (Daucuscarota)

2.3 The Genus Salmonella

2.3.1Salmonella and Processed foods 

2.3.2 Epidemiology for non-typhoid Salmonella infections

2.4 Preventing Food Spoilage 

2.4.1 Pre-harvest and Harvest Factors

2.4.2 Decontamination of vegetables

2.5    Antibiotic Resistance 

CHAPTER THREE

3.0       Materials and Methods

3.1 Sample Collection

3.2 Culture Media preparation

3.3 Preparation of samples

3.3.1 For the Isolation of Salmonella Species

3.4 Gram Staining

3.5 Biochemical Tests

3.5.1 Catalase Test

3.5.2 Indole Test

3.5.3 Citrate Utilization Test

3.5.4 Hydrogen Sulphide (H2S) Production Test

3.6 Antibiotics Sensitivity Test 

3.7 Stress Tolerance Assay

CHAPTER FOUR

4.0  Results

CHAPTER FIVE

5.0       Discussion, Conclusion and Recommendation

5.1 Discussion

5.2 Conclusion

5.3 Recommendation

References