Microbiological And Microbial Assessment Of Commercially Prepared Yoghurts Sold In Enugu

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). 

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. 

 

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