AUGUST 2010.
Ten (10) samples of suya meat in Enugu were collected randomly and analyzed microbiologically and the isolates were identified as Staphylococcus aureus (35%) Escherichia coli (15%) Streptococcus species (15%) Pseudomanas (35%) . The most frequently isolated organism was Staphylococcus and Pseudomonas. The total viable bacterial counts ranged from 1.9x  3.8x  cfu/g whereas, total coliform count ranged 1.1x -3.0x  cfu/g on MacConkey and Nutrient agar respectively. The result revealed that the hygienic condition of the meat have fallen below acceptable standard for human comsumption.
TABLE 1: Total viable and coliform counts ( )
TABLE 2: Characterization /identification of Isolate
TABLE 3: Frequency of occurrence of isolates
                                 TABLE OF CONTENTS 
Certification                                                                                                     i
Dedication                                                                                                     ii
Acknowledgement                                                                                        iii
Tableofcontents                                                                                                    iv
List of Tables                                                                                                v
1.0 Introduction                                                                                            1
1.1 Objectives                                                                                                 4
2.0 Literature review                                                                                     5
2.1Suya meat                                                                                                 5
2.2 Preparation of suya                                                                                      5
2.3Preparation of meat
2.4 Meat spoilage
2.5 Factors that affect the growth of microorganisms in meat
2.5.1 Temperature
2.5.2 pH
2.5.3. Water availability
2.5.4 Nutrients
3.0 Materials and methods
3.1 List of reagents
3.2 List of glassware
3.3 Preparation of media
3.4 Sample collection
3.5 Preparations of samples
3.6 Determination of total viable counts
3.7 Characterization and Identification of Isolates
3.7.1 Gram reaction
3.7.2 Motility test
3.7.3 Catalase test
3.7.4 Coagulase test
3.7.5 Oxidase test
3.7.6 Urease test
3.7.7 Citrate test
3.7.8 Vogues Proskauer test
3.7.9 Indole test
3.7.10 Carbohydrate fermentation test
3.7.11 Methyl red test
4.0 Results
5.1 Discussion
5.2 Summary and Conclusion
5.3 Recommendations
TABLE 1: Total viable and coliform counts ( )
TABLE 2: Characterization /identification of Isolate
TABLE 3: Frequency of occurrence of isolates
                                      CHAPTER ONE
1.0                               INTRODUCTION


Meat is the flesh of animals which serves as food; it is obtained from sheep, cattle, goat and swine (Hamman, 1997). Meat is a major source of protein and have valuable qualities of vitamins for most people in many parts of the world, thus they are essential for the growth, repair and maintenance of body cells which is necessary for our everyday activities.
Meat could be traced back to human history, then when primitive men use raw flesh of dead animals, but as man developed, he domesticated as well as wild animals. Beef have been the major supply of meat in Nigeria as a result of extensive and semi-intensive cattle production system in Nigeria by Fulani and Hausa people of the northern Nigeria. (Umoh, 2004).
Suya meat is a boneless lean meat of mutton, beef, goat or chicken meat staked on sticks, coated with its sauces, oiled and then roasted over wood using a fire from charcoal. It is a popular, traditionally processed meat product that is served hot and sold along streets, at clubs, picnics centers, and restaurants and within institutions. Suya meat is one of the intermediate moisture products that are easy to prepare and highly relish which is a mass consuming fast food and its preparation and sales are usually not done with strict hygiene condition because they are still done locally.
Due to the chemical composition and characteristic, meat are highly perishable food which provides excellent source of growth of many hazardous microorganisms that can cause infection in human and also lead to meat spoilage and economic loss. The most important bacteria meat spoilage is caused by lactic acid bacteria which is physiologically related group of fastidious and ubiquitous gram-positive organisms, these includes many species such as Lactobacillus, Leuconostoc, Pediococcus and Streptococcus.
Since meat has a high nutritive value, microorganisms could easily grow on it. The possible sources of contamination are through slaughtering of sick animals, washing the meat with dirty water, handling by butchers, contamination by flies, processing close to sewage or refuse dumps environment, spices, transportation and use of contaminated equipment such as knife and other utensils. (Igyor and Uma, 2005).
The slaughtering process affords extensive contamination of sterile tissue with gram-negative enteric bacteria from animal intestine including Salmonella specie and Escherichia coli as well as contaminant such as gram-positive Lactic cocci associated with humans, animals and the environment. Enterococci and Clostridia have been isolated from lymph node of red meat animals (Lawries, 2000, Alexander et. al. 1998).
Microorganisms grow on meat causing visual, textural and organoleptic changes when they release metabolite (Jackson et. al. 2001). The smoke produced as a number of effects including preservative effect resulting from the deposition of organic compounds all presents in the smoked product (Suya meat). (Dineen et.al.1999). A preservative effect is also induced by the surface drying that occurs to the extent of 30% total weight loss in hot smoked product. Antioxidant effect is produced by the phenolic deposite unto the product.
The microbial load in meat and meat product increases as long as growth conditions are favorable. The factor influencing microbial growth includes acidity pH, temperature, water activity, gaseous requirement, nutrient and competition of microbes for the nutrient. Controlling these factors implies maintaining long shelf life of meat and meat product but proper preservation of meat could be achieved by the combination of two or more preservation method which includes drying, salting and high temperature (Nester e, al 2001).
1.2                     AIMS AND OBJECTIVES
This work is aimed at determining the microbial quality of suya meat sold in Enugu and has the following objectives:

  1. To isolate, characterize and identify microbial species associated with Suya meat.
  2. To establish the public health implication of consumption of Suya meat.
  3. To offer useful information where necessary to the consuming public.

2.1     SUYA MEAT
Suya meat is a traditional stick meat product that is commonly produced by the Hausas in West Africa from beef, although chicken can also be used. It is produced from boneless meat hung on stick and spiced with peanut, cake, salt, vegetable oil and other flavor followed by roasting around a glowing charcoal fire. The smoke from the fire has a preservative effect on the Suya meat (Ogunbanwo et. al. 2004).
Usually in Nigeria, skinless, boneless flesh of cattle or chicken is used for commercial preparation of suya meat. Finely grounded roasted peanut cake, red pepper, salt, grounded ginger, grounded garlic, chunked fresh tomatoes and  minced fresh onions are required on suitable conditions depending on the quality of suya meat required to be prepared (Jay, 2000; Judge et. al.2000).
The process of preparation involves a few steps, first is the grounding of peanut. The shell and the skin are removed from the peanut before grinding into fine powder using mortar and pestle or crushed with a rolling pin. If the powder is oily; it is wrapped with an absorbent paper and squeezed for a minute or two. Next, the grinded pepper, garlic, ginger are stirred into the obtained peanut powder and mixed properly.
The meat is then cut into bit sizes or thin sliced, dipped and rolled in a bowl containing the mixed peanut-spice and allowed to coat completely. The minced or mutton meat are then kept for thirty minute or more for the peanut cake to stick to it after which the meat slices are threaded unto skewer and brushed with vegetable oil and roasted on the glowing charcoal fire for fifteen to twenty  minute. It is finally removed from the skewer and served hot in a newspaper with sliced onions, tomatoes and cabbage  (Judge et. al.2000).
Microorganisms destroy the inherent defense mechanism of the animal thereby subjecting the tissue to rapid decay as a result of its action (Lidwell et. al. 1996).
During slaughtering process, there is contamination of the sterile tissue with intestinal flora like gram-negative organisms which includes Escherichia coli as well as contaminants such as Pseudomonas specie and gram-positive lactic acid bacteria and Staphylococci specie associated with human, animals and their environment. Meat spoilage is usually associated with gram-negative Proteolitic bacteria which literally decompose the protein with production of offensive odour (Hamman, 1997).
The addition of salt and drying of fresh meat have been an effective means to control the meat micro flora and thus preserve the tissue for later consumption. The curing salt (sodium chloride, sodium nitrate and sodium nitrite) and subsequent proper handling methods, favours the growth of gram-positive bacteria, primarily Staphylococcus aureus  while inhibiting the proliferation of gram-negative bacteria (Boles et. al. 2000).
There are also other types of common microorganisms apart from enteric organisms found in meat which are members of Micrococcaceae and Staphylococcaceae families. The predominant types are coagulase-negative Stapylococci that are salt tolerant and can also grow with or without oxygen. The most common strain belongs to the species of Stapylococcus carnosus, S. xylosus and S. kocuria variance by far. However, these organisms are harmless and do not present a microbial hazard.  The most common lactic acid microorganisms found in fermented meat of various strains of Lactobacilli, Leuconostoc, Pediococci, Streptococci and Enterotocci (Lawries, 2001).
Bacillus species, Staphylococcus aureus, Staphylococcus epidermidis, Proteus species, Serratia species and Aspergillus species were isolated from suya  meat samples collected from Enugu state (Chukwura and Mojekwu, 2002).
Meat is spoilt when it loses its nutritive value, texture and brings out offensive odour thus rendering it unfit for human consumption. A number of factors could cause meat spoilage (Nester et .al.2001).
Most deterioration or spoilage of meat could be caused by bacteria, yeast and mould. When meat is not properly handled, it leads to spoilage (microbial spoilage which makes it unfit for human consumption) (Sokari  et. al. 1999).
A lot of factors affect the growth of microorganisms on meat. This factors includes temperature, pH, water availability, presence of nutrients, moisture, acidity (intrinsic factors), gaseous requirement, atmosphere of storage(extrinsic factors) (Nester et  al; 2001).
Microorganisms have optimum, minimum and maximum temperature that they can grow. Listeria monocytogenes have been found to grow at C and even survive freezing. This ability of growing at low temperature provides opportunity for proliferation in contaminated meat products (Fraizer and Westhoff, 2000).Pseudomonas specie grow at temperature less than 20 and so are found.(Dineen et al;1999).
Psychrophiles have temperature optimal between C and C mesophiles between C and C and thermophile from C or C (Fararatti, 2000).
Examples of psychrophiles are

  1. Achromobacter
  2. Alcaligens
  3. Pseudomonas
  4. Streptococcus
  5. Salmonella
  6. Most yeast

Examples of mesophiles are Bacillus strearothermophiles (Evans and Niren, 1980).
2.5.2 pH
Most bacteria grow optimally at above pH 7 and not well below pH 4 or above pH 9 (Abdul Raouf et al; 1995). But the pH of maximal growth is determined by the simultaneous operation of variables other than the degree of acidity or alkalinity itself proteolitic enzyme operate best near neutral pH 7.
Water is required by microorganism so reducing water below the optimum level which prolong shelf life of meat. If meat is stored at a relative humidity below 95% moisture will be lost from the surface. Since most spoilage bacteria can grow only on the surface, drying the meat. Surface will not favor their growth but staphylococcus aureus can grow in meat with 0.86 which is lower than that of other spoilage bacteria (Nester et al; 2001). Moulds are able to grow in drier conditions than bacteria so that desiccation has a selective effect on microbial growth. Xerphilic fungi have been found to grow at a low temperature 0.6 (Evans and Niren, 1999).
Microorganisms depend on nutrients from meat product or meat for survival. Meat contains protein, phosphorus, fat and vitamins, which support the growth of microorganism. Pseudomonas aeruginosa synthesize it vitamins and so cause spoilage even in a medium without vitamin. Staphylococcus aureus require about 6.5% of sodium chloride for growth and is usually found in salty meat product (Boles et al; 2000).

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