SCREENING OF LACTIC ACID BACTERIA FROM UNRIPE FRESH PEPPER AND THEIR EFFECT ON POTENTIAL SPOILAGE ORGANISMS

SCREENING OF LACTIC ACID BACTERIA FROM UNRIPE FRESH PEPPER AND THEIR EFFECT ON POTENTIAL SPOILAGE ORGANISMS

Project Details

SCREENING OF LACTIC ACID BACTERIA FROM UNRIPE FRESH PEPPER AND THEIR EFFECT ON POTENTIAL SPOILAGE ORGANISMS



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Description

Lactic acid bacteria (LAB) are important because they can produce substances with pleasant sensory characteristics during meat processing. Moreover, the action of various antimicrobial compounds produced during the fermentation process, such as lactic acid, acetic acid and propionic acid, may result in an unfavourable environment for the development of spoilage and pathogenic microorganisms. Therefore, this study examined the screening of lactic acid bacteria on unripe fresh pepper and the effect on potential spoilage organisms. Five (5) sets of unripe pepper (Capsicum annum) were purchased in Ago-Iwoye Market, Ijebu-North Local Government Area, Ogun State, Nigeria and transferred immediately to the Olabisi Onabanjo University Microbiology Laboratory for further bacteriological analysis. Samples were serially diluted and plated on different media using pour plate method according to standard procedures. The colonies were identified by comparing their morphological and biochemical characteristics with standard reference organisms. A total of sixteen isolates comprising of three different genera of LAB were isolated from unripe pepper. The genera were Lactobacillus, Leuconostoc and Lactococcus. The lactic acid bacteria showed inhibitory effect on growth of potential pathogens which include Bacillus subtilis, Staphylococus aureus, Escherichia coli, Klebsiella spp., Pseudomonas aeruginosa, Proteus mirabilis. The total lactic acid bacteria count on the unripe pepper ranged between 1.1 x 106 – 3.2 x 106 cfu/m. It was revealed in this study that lactic acid bacteria demonstrated a promising and potent antimicrobial activities which can be harnessed for medical and commercial purposes especially in the treatment of diseases caused by pathogenic organisms.
TABLE OF CONTENTS
CHAPTER ONE
1.1 Introduction
1.2 Justification
1.3 General Objective
1.4 Specific Objectives
CHAPTER TWO: Literature Review
2.1 Overview of Lactic Acid Bacteria
2.2 Bacteriocin
2.2.1 Bacteriocins produced by lactic acid bacteria
2.3 The Antimicrobial Action of LAB in Food Preservation
2.3.1 Organic Acids, Acetaldehyde and Ethanol
2.3.2 Hydrogen Peroxide
2.3.3 Carbon Dioxide
2.3.4 Diacetyl
2.3.5 Reuterin
2.4 Biopreservation of Vegetable Products
CHAPTER THREE: Materials and Methods
3.1 Study Area
3.2 Sample collection
3.3 Media Used
3.4 Sample Analysis
3.5 Isolation and Identification of the Bacteria
3.5.1 Isolation and Identification of Lactic Acid Bacteria
3.5.2 Gram’s Staining Reaction
3.5.3 Coagulase Test
3.5.4 Sugar Fermentation Test
3.5.5 Nitrate Reduction Test Procedure
3.5.6 Motility Test
3.5.7 Catalase Test
3.5.8 Oxidase Test
3.5.9 Indole Production Test
3.6 Microscopy Morphology
3.7 Test Bacteria
3.8 Detection of Antimicrobial Activity
CHAPTER FOUR: Results
CHAPTER FIVE: Discussion, Conclusion and Recommendations
5.1 Discussion
5.2 Conclusion
5.3 Recommendation
REFERENCES
LIST OF TABLES
4.1 Mean Count of Lactic Acid Bacteria in Unripe Pepper (Capsicum annum)
4.2 Morphological and Biochemical Characteristics of Isolates Recovered from Unripe Pepper
4.3 Incidence and Occurrence of LAB in Unripe Pepper (Capsicum annum) Samples Sold in Ago-Iwoye and Ijebu-Igbo
4.4 Total Count of the Bacteria Organism Isolated from Unripe Fresh Pepper (Capsicum annum)
4.5 Number and Percentage Occurrence of Spoilage Organism Isolated from Unripe Fresh Pepper (Capsicum annum)
4.6 Antimicrobial Effect of Lactic Acid Bacteria on Potential Pepper (Capsicum annum) Spoilage Bacteria

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