Yoghurt is a cultural diary product produced by lactic fermentation of milk (Hui, 1992). Yoghurt is produced by the controlled fermentation of milk by two species of bacteria; Lactobacillus bulgaricus and Strptococcus thermophilus.
These two species of bacteriae have now been established as the yoghurt starters.
Any sort of milk may be used to make yoghurt, but modern production is dominated by cow milk. It is the fermentation of the milk sugar (Lactose) into lactic acid that gives yoghurt its gel-like texture and characteristics tang (Davis, 1974).
ABSTRACT
Fermented milk products such as yoghurt contain bacteria from the lactobacilli group. These bacteria occur naturally in the digestive tract and have a cleansing and healing effect.
The objective of this study was to investigate the level of microbial contamination of yoghurts sold in Enugu Urban.
Six different brands of bottle packaged yoghurt were brought from hawkers and beverage stores in Enugu Urban. Each sample was serially diluted using sterile distilled water as diluents (Prescolt et al 2002) and Iml of 10-3 sample was plated in duplicate using the pour plate method on MacConkey agar and nutrient agar media the plates were incubated at 370C for the 24hrs.
The result obtained from the microbiological analysis showed that product were contaminated by microorganisms of public health concern the high heterotrophic bacterial and coliform counts may be a consequence of low level of hygiere maintained during the processing by some of the producers of the product.
TABLE OF CONTENTS
CHAPTER ONE
INTRODUCTION
CHAPTER TWO
LITERATURE REVIEW
Chemical Composition Of Milk
History of Yoghurt
Traditional Method of Yoghurt Production
Processing Of Yoghurt
Yoghurt Quality
Yoghurt Pasteurization
Yoghurt Preservation
Refrigeration of Yoghurt
Yoghurt Flavour
Quality Control of Yoghurt
Microbiological Analysis
Pathogenic Bacteria
Yoghurt Spoilage
Biochemical Analysis
Yoghurt pH
CHAPTER THREE
Materials And Methods
Sample Collection
Analysis Of Sample
Identification Of Isolates
Bacteria Identification
Biochemical Tests
CHAPTER FOUR
Results
CHAPTER FIVE
Discussion
Conclusion And Recommendation
Reference
Appendix