ABSTRACT
Microbial assessment of Abacha sold within Michael Okpara University of Agriculture Umudike campus was investigated. Samples of abacha were purchased from ten food vending sites within the university campus. Overall, the results showed that Bacillus sp., Staphylococcus aureus, Escherichia coli, Klebsiella sp., Salmonella sp., Shigella sp. and Serratia sp. were the predominant bacterial isolates identified from the abacha samples. While Fusarium oxysporium, Aspergillus flavus, Aspergillus niger and Rhodotrorula sp. were the predominant fungal isolates. The total coliform plate count; total Salmonella Shigella plate count; total heterotrophic plate count; total fungal plate count obtained from this study were higher than 106 tolerable level of microbial load in foods. The results revealed a high percentage occurrence on the abacha of the following bacteria Escherichia coli (29.55%), Staphylococcus aureus (14.55%) and a low percentage occurrence of Serratia sp. (9.09%) and Bacillus sp. (6.81%). The results revealed a high percentage occurrence on the abacha of the following fungi Fusarium oxysporium (13%), Rhodotorula sp. (11%) and a low percentage occurrence of Aspergillus flavus and Aspergillus niger (8%) respectively. The results from this study revealed that high level of contamination was recorded in all the abacha samples with the abacha sample from Gate 6 having the highest level of contamination and the lowest recorded in the abacha sample from stadium. The results of the study therefore, calls for stringent supervision and implementation of food-safety practices and regular education on food and personal hygiene among food handlers and the general public on food safety measures, effective Hazard Analysis Critical Control Point (HACCP) application and Good Manufacturing Practices (GMP) implementation is imperative. Special care however, has to be taken in its preparation as contaminants could be introduced through the ingredients.
TABLE
OF CONTENT
Title Page
i
Certification
ii
Dedication
iii
Acknowledgments
iv
Table of Contents
v
List of Tables
vii
List of Figures
viii
Abstract
ix
CHAPTER
ONE
1.1 Introduction 1
•
Statement of problem 3
1.3 Justification 3
1.4 Aims and Objective of the study 4
1.4.1 Main Objective 4
1.4.2 Specific Objective 4
CHAPTER
TWO
2.1 Literature Review 5
2.2 The Nigerian Cassava Industry 6
2.3
Nutritional Value of Cassava Roots 7
2.4
Secondary Products from Cassava 10
2.5 Microbial Analysis of Street Food 13
2.6 Street Food 14
2.7 Importance of Street Food in
Urban Areas 15
2.7.1 Nutritional Benefits 16
2.7.2 Economic Benefits of Street Food 17
2.8 Preparation of Street Food 17
2.9 Sources of Contaminants in
Street Vended Foods 19
2.9.1 Food Handling 19
2.9.2 Waste Disposal 19
2.9.3 Water 20
2.9.4 Other Raw Materials 20
2.9.5 Utensils and Equipment’s: Chemical and
Microbial Contaminants 21
2.9.6 Chemical
Contaminants 21
2.9.7 Storage 22
2.9.8 Reheating 23
2.9.9 Personal Hygiene of the Vendors or Food
Handlers 23
2.10 Microbial Safety of Foods 24
2.10.1 Food Borne Diseases 24
2.10.2 Microbial Safety of Street Food 25
2.11 Epidemiological Importance of Microbial
Food Borne Disease in Street Foods 25
2.12 Gaps in Knowledge on Street Food Safety 26
CHAPTER THREE
MATERIALS
AND METHODS 27
3.1 Study Area 27
3.2 Materials 27
3.3 Methods for Microbiological Analysis 27
3.3.1 Sample Collection and Processing 28
3.3.2 Microbiological
Analysis of Samples 28
3.3.2.1 Total Bacterial count 28
3.3.2.2 Total Fungal count 28
3.3.2.3 Coliforms/Staphylococcus aureus/Salmonella 29
3.3.2.4 Inoculation of Media for
Characterization and Identification 29
3.3.2.5 Enumeration and Characterization of
Microbial Isolates 30
3.3.2.6 Total Coliform Test 30
3.3.2.7 Determination of Percentage Occurrence 31
3.4 Statistical analysis of data 31
CHAPTER
FOUR
4.0 RESULTS AND DISCUSSION 32
4.1 Result 32
4.2 Discussion 42
CHAPTER
FIVE
5.0 CONCLUSION AND RECOMMENDATION
46
5.1 Conclusion 46
5.2 Recommendations 46
REFERENCES
APPENDICES
LIST
OF TABLES
Table 1: Nutritional Composition of Cassava 9
Table 4.1 Mean Total bacterial counts of Abacha from the various
sites (Cfu/g) 32
Table 4.2 Mean Total Fungal counts of Abacha from the various
sites (Cfu/g) 33
Table 4.3: Occurrence of Presumption Coliform in
Tubes of the MPN Abacha 34
Table 4.4 Percentage of occurrence/ No. of
Positive Occurrence of Bacterial
Isolates from Abacha 35
Table 4.5 Percentage of occurrence/No. of
positive occurrence of fungal isolates from
Abacha 36
Table 4.6: Morphological and biochemical
characteristics of bacterial isolates from
Abacha 37
Table 4.7 Morphological and biochemical
characteristics of fungal isolates from Abacha
39
LIST
OF FIGURES
Figure 4.1: Bar Chart showing the Total
Microbial contamination on Abacha sold within MOUAU Campus 41
CHAPTER ONE
INTRODUCTION
In Africa, cassava has been reported to be among
the most crucial food and Nigeria is the largest producer of cassava in the
world (FAO, 2017). Cassava is a major staple crop in Nigeria, and its products
are found in the daily meals of Nigerians. Cassava accounts for a daily caloric
intake of 30% and is grown by nearly every farming family (Onyenwoke and
Simonyan, 2014)
Guira et al. (2016) reported that cassava root needs to be processed.
Moreover, in Nigeria, majority of people prefer to consume cassava in fried,
baked or in boiled form after fermenting the raw cassava crop.
Cassava is the third most important source of
calories in the tropics after rice and maize (Food Safety Network, 2014). Its
processed products contain an important proportion of carbohydrates (mainly
starch) and minerals (Guira, 2013).
African salad popularly called “Abacha, Abacha
Ncha, Abacha and Ugba” by Igbo tribe of Nigeria, is an exotic delicacy and a
special salad recipe native to Nigeria (Oranusi et al., 2013). The name African salad is thought to have originated
from the Igbo’s ideology that salad contains lots of fresh and raw vegetables
and some other ingredients consumed without further cooking, therefore it is a
salad and of African origin (Oranusi et
al., 2013; Daniel et al., 2016).
African salad is widely accessed for its
composition of food ingredients known to be rich in protein, carbohydrate,
vitamins, and minerals (Oranusi et al.,
2013). African salad is also regarded as a special delicacy during traditional
festivals (Maky, 2013).
Abacha is processed by harvesting cassava
tubers, after which they are peeled, washed and cooked. These are then shredded
into fine thin slices, and soaked overnight for fermentation so as to
thoroughly reduce the starch and hydrogen cyanide from the cassava. The
shredded and fermented cassava is again thoroughly washed the following day
before drying it for 2-3 days (Oranusi et
al., 2013).
The preparation of African salad takes great
efforts and the ingredients needed to prepare .It vary according to one’s taste
and availability. The key to making a good African salad is to ensure that all
the ingredients are well incorporated. It can include ingredients such as Ugba
(Pentaclethra macrophylla), palm oil,
potash, onions, nutmeg, crayfish, salt, pepper, maggi, ogiri (Ricinus communis), garden egg, garden
egg leaves, Utazi leaves (Gongronema
latifolium), Okazi (Ukazi) leaves (Gnetum
africana), Ozeza (Uzeza) leaves (Piper
guineense), kpomo (cow skin), meat and stockfish/fish (Daniel et al., 2016; Miriam and Anthonio, 2011;
Maky, 2013). These ingredients are mixed thoroughly with the shredded cassava
(Abacha). The ingredient added is dependent on one’s choice, purchasing power
and availability. African salad can be served with fried fish/meat over a cold
drink (Palm wine, beer, stout or wine) (Miriam and Anthonio, 2011; Osewa,
2013).
Street vended foods offer convenient access to
ready meals to those who do not have cooking utensils or skills or convenience
to prepare them regularly at home. The overall health benefits of
these-ready-to eat foods vended on the streets in developing countries are
numerous. (Obaji et al., 2018).
According to World Health Organisation (WHO),
waterborne and foodborne diarheoal disease kills about two million people annually
(WHO, 2003)
1.1
STATEMENT OF PROBLEM
According to Daniel et al. (2016), Street- vended foods such as African salads are
frequently associated with diarrhea diseases due to the presence of pathogenic
bacteria, environmental contaminants, and disregard for good hygiene practices
(GHPs). The vendors of these foods are often poorly educated and untrained in
food hygienic processes and they work under crude unsanitary conditions with
little or no knowledge about the causes of food borne disease.
African salads can be contaminated from the
different ingredients during preparation. It contains raw vegetables and other
ingredients that are consumed without further heating. A major ingredient which could serve as a major
source of contamination to Abacha is the raw vegetables. Vegetables have been
associated with outbreaks of food borne disease in many countries (Eni et al., 2010). Raw vegetables harbor
many microorganisms through contact with soil, dust, water, handling at harvest
or during processing and these microorganisms may be found in the final product
(Itohan et al., 2011).
1.2
JUSTIFICATION
Food-borne illnesses of microbial origin are a
major health problem associated with street vended foods. In addition, there is
paucity of information on the microbiological compositions of African salad (Abacha) as consumed, which is regarded
to be nutritionally rich by many consumers.
This research provides information on the
microflora composition of this exotic delicacy with a view to stimulate further
research and thus build a compendium on the microbial diversities of different
preparations of this all important African dish.
1.3 AIMS AND OBJECTIVE OF THE STUDY
1.3.1 Main Objective:
The present study was aimed at studying the
microbial assessment of African salad (Abacha) sold within Michael Okpara
University of Agriculture Umudike Abia State (MOUAU) campus.
•
Specific Objective:
The specific objective of this study was to;
•
To assess and identify the bacterial composition
of the sample.
•
To assess and identify the fungal composition of
the Abacha samples.
•
To determine the antibiotic sensitivity and
resistance of the isolates.
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