Isolation Of Spore Forming Bacteria From Spices

Description

ABSTRACT

Spices are mostly produced in developing countries on small farms using traditional production methods. Spices become contaminated by bacterial spores in two main ways: by contact with soil during harvesting or drying, as for pepper, or by cross-contamination during the water-cooking step. The aim of this work is to study bacteria associated with common spices to understand if any harm they can cause to the consumers. A total 40 spores- formers Bacillus were isolated from different spices samples were characterized using Biochemical test, growth on Chromogenic media and further characterization by PCR technique. Results showed variation in biochemical test as well as the total count was higher with fennel spice 44.6 × 10 ⁵ and lesser count with Shawerma spice 0.21 × 10 ⁵. Seven isolates were identified with gene-specific PCR. In conclusion it is clear that raw spices may be contaminated with microbial pathogens and spores forming Bacillus.

TABLE OF CONTENTS

 TITLE PAGE

APPROVAL PAGE

DEDICATION

ACKNOWELDGEMENT

ABSTRACT

TABLE OF CONTENT

CHAPTER ONE

1.0     INTRODUCTION

1.1     Background to the Study

1.2     Statement of Problem

1.3     Aim and Objectives

CHAPTER TWO

LITERATURE REVIEW

2.1      Overview of the study

2.2      Overall levels of spore-forming bacteria

2.3      Review of different species

2.4      Review of the related studies

CHAPTER THREE

3.1      MATERIALS AND METHODS

3.1      Bacillus Isolation

3.2      Chromogenic media

3.3      Chemical and biochemical tests

3.4      Extraction of chromosomal DNA from Bacillus

3.5      PCR amplification and analysis of 16S Rrna

CHAPTER FOUR

4.0     RESULT

4.1     Bacterial Morphology, Chemical and Biochemical Tests

CHAPTER FIVE

5.1     Conclusion and Recommendation

REFERENCES

CHAPTER ONE

1.0                                              INTRODUCTION

1.1                                BACKGROUND TO THE STUDY

Spices is a term generally means a group of substances of vegetable origin rich in aromatic and resinous principles and essential oils used as a condiment or, if necessary, in the pharmaceutical sector and cosmetics (Brackett, 2017). At the time of collection, an inevitable contamination by the most different microorganisms originating in soil, in particular aerobic spore-forming bacteria and anaerobes (FAO, 2018). Most of them, moreover, are produced in tropical and subtropical countries where conditions general hygiene may be lacking, for which if not properly handled and stored, represent an important source of food contaminations to which they are added (Sagoo, 2019). Spices are dried and consequently have a low active water value, this means that the products are microbially stable (Freitas, 2012). Because of their origin and the way of drying, they are highly microbially contaminated, after rehydrations by addition of moist ingredients, the end of products are susceptible to spoilage (Guarino, 2012). In order to reduce the contamination of these products and the potential hazards arising from their use, the use of decontamination techniques, such as irradiation, is of fundamental importance. Testing of spices for pathogens is useful to screen for high rates of contamination entering a plant (Guarino, 2012). Although spices have not been historically associated with outbreaks or product recalls due to some bacterial pathogens (e.g. Listeria monocytogenes, Clostridium perfringens, Bacillus cereus, Staphylococcus aureus, etc.), they have been associated with foodborne illness due to E. coli and Salmonella contamination (Mousumi, 2012). Bacteria in the spices such as Bacillus can cause a variety of foodborne illnesses especially when the spiced food are improperly refrigerated or when leftovers are improperly stored for several days (Mousumi, 012). The main impact being on public health risks is when using these spices and herbs as an addition to ready-to-eat foods. This is especially true for those that undergo little further processing after being added to these foods. Studies have shown that overall 3.0 % of herbs and spices contained high counts of B. cereus (Mousumi, 2012). The present work was aimed to study bateria associated with common spices to understand if any harm they can cause to the consumers.

1.2                                    STATEMENT OF PROBLEM

Production and world consumption of spices are constantly increasing. Although the antimicrobial properties of some spices are well documented, their use in the agri-food industry is also responsible for microbial contamination and spoilage. The high level of spice contamination by bacterial spores is a serious problem for the food industry. Spices may be contaminated because of the conditions under which they were cultivated and harvested. Contaminated spices have been reported to have been the causes of certain food-borne illnesses and spoilage (Giese, 2014).

The microbiological contamination of spices may arise from sources, such as indigenous microflora of plants, microorganisms present in processing plant, air, post harvest contamination from dust, use of contaminated water and from human contact, (Wirtanen and Sjoberg, 1993). During cleaning and processing, there is progressive reduction in the number and types of microorganisms; those remaining are usually aerobic spore-forming bacteria and common moulds (Guarino, 1973). The studies cited in this review show high prevalence of bacterial spores, especially in spices such as black pepper and spice blends. High spore concentrations are observed in highly used spices such as pepper and turmeric.

1.3                                        AIM AND OBJECTIVES

The main aim of this work is to study bacteria (mainly on Bacillus spp.) associated with common spices and to understand if any harm they can cause to the consumers.

The objectives of this work are:

1. To analyze the published data on the prevalence and levels of bacterial spores found in herbs and spices.
2. To identify the potential sources of bacterial spore contamination of spices to improve spice preparation processes, and thus, limit the potential contamination.