ABSTRACT
Thirty samples of four different parts of chicken varieties were analyzed to determine their microbial flora; the samples were collected from cold rooms, local market and super markets. All the chicken parts examined (Gizzard, Wings, Legs and Laps) were contaminated. The isolates include Staphylococcus, Escherichia spp., Pseudomonas, Salmonella spp, Aspergillus and Penicillium spp. Samples from supermarkets for all the chicken parts produced 1.3x101 – 3.2x102 cfu/g, those from local markets gave a range of 1.2x102 – 9.3x103 cfu/g and those from cold rooms gave a range of 1.1x101 – 1.5x103. These findings suggest that most of the frozen chicken parts stored in the open market may constitute sources of bacterial food poisoning and consequently health hazard.
TABLE OF CONTENTS
Title page i
Certification ii
Dedication iii
Acknowledgments iv
Table of Contents v
List of Tables viii
Abstract ix
CHAPTER ONE
1.1 Introduction 1
1.2 Aims and objectives 3
CHAPTER TWO
2.0 Literature review 4
2.1 Microorganisms associated with poultry 7
2.1.1 Salmonella enteritidis 7
2.1.2 Staphylococcus aureus 7
2.1.3 Campylobacter jejuni 7
2.1.4 Listeria monocytogenes 7
2.2 Spoilage organisms 7
CHAPTER THREE
3.0 Materials and methods 9
3.1 Materials 9
3.2 Methods 9
3.2.1 Collection of samples 9
3.2.2 Sterilization of materials 9
3.2.3 Media preparation 9
3.2.4 Sample preparation 10
3.2.5 Inoculation of sample 10
3.2.6 Identification of isolates 10
3.2.7 Gram staining 10
3.2.8 Motility test 11
3.2.9 Biochemical characteristics of isolates 11
3.2.9.1 Catalase test 11
3.2.9.2 Coagulase test 11
3.2.9.3 Oxidase test 12
3.2.9.4 Citrate test 12
3.2.9.5 Methyl Red test 12
3.2.9.6 Indole test 12
3.2.9.7 Vogues Proskauer test 13
3.2.9.8 Sugar fermentation test 13
3.2.10 Spore staining 13
3.2.11 Fungal isolation and identification 13
CHAPTER FOUR
4.0 Results 14
CHAPTER FIVE
5.0 Discussion and conclusion 20
5.1 Discussion 20
5.2 Conclusion 21
REFERENCES
LIST OF TABLES
TABLES TITLE PAGE
1.1 Nutritional value of chicken meat 4
1.2 Principal bacteria and yeasts associated with spoilage of stored frozen poultry meat in modified atmosphere or air 8
4.1 Bacterial counts on the different chicken parts from supermarket15
4.2 Bacterial counts on the different chicken parts from local market 16
4.3 Bacterial counts on the different chicken parts from cold rooms 17
4.4 Identification and characteristics of bacterial isolates 18
3.5 Characterization of moulds from frozen chicken 19
CHAPTER ONE
1.1 INTRODUCTION
The skin of live birds may contain a number of bacteria averaging 1.5x103 per square centimeter. This number probably reflects the natural flora of the skin plus other organisms that could be derived from feet, feathers and faeces. (Frazier and Weahoff, 1988). During the various stages of slaughter and processing, all potential edible tissue are subjected to contamination from a variety of sources within and outside the animal (Kozacinski, et al., 2006) and also from the environment, operators and equipment (Mead, et al., 1989).
Bacterial load vary considerably on surfaces of chickens. This variation however is greater between birds than is between different areas of the same birds. Fresh poultry products like meat are known to undergo detoriotion due to microbial action, chemical and physical changes. In normal handling and storage of poultry meat this deteriotion changes are attributed to microbiological contamination and activity. Like all fresh foods, chickens carries natural microflora that may contain organisms potentially harmful to humans, the microbial flora of table poultry is largely confined to the skin or visceral cavities isolates from poultry and poultry products could include members of the following genra Enterobacter, Alcaligens, Escheriachia, Bacillus, Flavobacterium, Micrococcus, Proteus, Pseudomonas, Staphylococcus, Corynebacterium and Salmonella (Frazier and Westhoff, 1988).
The center for disease control in the United States of America has estimated that these pathogens are together responsible for 3.9 million foodborne illnesses and 1600 deaths each year (Mead, et al., 1999). As a result of variation in the processing technology, large variation occur in the microbial loads of raw poultry meat (Kilinger, et al., 1981)
Since poultry meat itself offers an excellent medium for the multiplication of most bacteria, including those that are not inhibited by low temperatures, storage of processed poultry meat is vital and therefore considered under circumstances which inhibit the multiplication of the initial load of bacteria (Blankenship, 1996). Generally, the microbial quality of meat products including chicken processed by customers depends on factors such as the quality of the raw product and other materials used or added during processing operations to the product as extraneous contaminants; efficacy of cooking process; sanitation during processing and packaging; maintenance of adequate refrigeration from the processing to the retail level and to the consumers; and finally sanitation during handling at the retail end (Selvan, et al., 2007).
Despite efforts invested in improving hygiene procedures in the processing of poultry over the years, the product continues to be heavily contaminated with various years, the product continues to be heavily contaminated with various organisms (WHO, 1986). Several efforts to reduce the microbial loads of chicken at various levels of production have generally been unsuccessful. Attempts to decontaminate chicken meat by the addition of chemicals to the processing water has only limited success (Sheldon and Brown, 1986). According to WHO (1989) the elimination of pathogenic microorganisms in poultry depends largely on the correct application of processing technologies such as pasteurization, irradiation, cooking, freezing and pickling at industrial, retail and domestic levels. Poultry should freeze fast enough to retain most of the natural bloom or external appearance of a freshly dressed chicken. The storage temperature should be below 17.80C and the relative humidity above 95 percent to reduce surface drying. Most poultry is sharp frozen at about 290C or less in circulating air or on a moving belt in a freezing tunnel (Frazier and Westerhoff, 1988).
1.2 AIMS AND OBJECTIVES
· To investigate the microbial quality of frozen chicken sold in umuahia at different retail outlets, namely supermarkets, local markets and cold rooms.
· To isolate and characterize the microbial load in the four different chicken parts (gizzard, wings, laps and legs).
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