ISOLATION, IDENTIFICATION, AND ANTIBIOGRAM OF Staphylococcus aureus ISOLATED FROM COW MEAT
Abstract
The study was carried out with aim to isolate Staphylococcus aureus from cow meat and determine the antibiogram pattern of S. aureus. Three samples of cow meat from three different locations (Gwagwalada market, Abattoir market and Kasuan Dare) in Gwagwalada were collected to isolate S. aureus from the samples. The organisms isolated were Salmonella spp, Escherichia coli, Staphylococcus aureus and Listeria monocytogenes. Several biochemical tests were carried out to identify, the S. aureus isolates like Catalse test (positive), Manitol test (positive), Coagulase test (positive) and Oxidase test (negative). The antibiogram pattern of S. aureus was evaluated using commercially prepared disk. The antibiotics tested were Pefloxacin (Pef), Streptomycin (S), Ampiclox (Apx), Amoxacilin (Am) and Ciprofloxacin. The pattern indicated that the overall S. aureus were resistant to Pef, S, Cpx and less resistant to Am and Apx. Results clearly suggested a possibility of potential public health threat of S. aureus resulting from contamination of cow meat with pathogenic bacteria which is mainly due to unhygienic processing, handling, and unhygienic environment.
CHAPTER ONE
1.0 INTRODUCTION
The right of a consumer is to have a product of good quality and not a product that will constitute any form of health hazard. Cow meat are highly desirable, palatable, digestible and highly nutritious. Cow meat is comprised of about 20-45% protein; others are water, fat, phosphorus, iron, vitamins and zinc (USDA, 2011). Quality products are those that meet some need or expectation of consumer and are safe and wholesome as well (Sahoo et al. 1996). The microbiological safety and quality of cow meat are equally important to producers, retailers and consumers. Two quite different groups of micro-organism are relevant: ones that are pathogens and ones that are generally harmless to human health, but being psychortrophic, they are able to multiply on the product during chill storage (Clay, 2004). Spoilage result mainly from off-odour development and product shelf-life is determined both by the number of spoilage organism present initially and the temperature history of the product at all stages of production and subsequent storage and handling (Pooni and Mead, 1984). For chill stored cow meat, Viehweg et al. (1989) demonstrated that virtually all the odourous substances found at spoilage could be attributed to microbial growth and metabolism. Contamination of cow meat with food borne pathogens remain an important public health issue, because it can lead to illness if there are malpractices in handling, cooking or post cooking storage of the product.
Fresh (uncooked) food such as cow meat caries natural micro flora that may contain organism potentially harmful to humans. The microbial flora of cow meat is largely confined to the skin surface. Isolates from cow meat could include members of the following genera Proteus, Enterobacter, Alcaligenes, Escherichia, Bacillus, Flavobacterium, Micrococcus, Pseudomonas, Staphylococcus and Salmonella (Frazier and Westhoff, 1988).
Contamination of the skin and lining of the body cavity occurs during washing, plucking and evisceration. Bacterial numbers vary considerably on the surface of the cow meat. This variation is greater between cows found in different location. The type of organism isolated depends upon where the samples are taken and upon the stage of processing (Frazier et al., 1985). Fresh cattle products like cow meat are known to undergo detoriation due to microbial action, chemical and physical changes. In normal handling and storage of cow meat, this detoriation changes are attributed to microbiological contamination and activity.
1.1 Contamination & Preservation of Cow Meat
Cow and cow products are frequently contaminated with several types of micro-organism. This problem is even more severe under temperature-abused conditions as well as improper or inefficient refrigeration commonly observed in retail cow meat sold in open markets. Cow meat can be kept in good condition for month if properly freeze and the storage temperature is low enough. Cow meat should freeze fast enough to retain most of the natural bloom of a freshly killed cow. The storage temperature should be below 17.8ºC and relative humidity above 95% to reduce surface drying. Most cow meat is sharp-frozen at about 29ºC or less in circulating air or on a moving belt in a freezing tunnel. Other spoilage micro-organism are introduced into the cow meat by the workmen during cutting and evisceration, through water, and air in the dressing, cutting and cooling room environment (Bhagirathi et al., 1982). However, various methods are used in the preservation of cow meat in order to reduce the incidence of these organisms. These include ascepsis, use of heat, use of low temperature, chilling, freezing, preservative such as asceptic, adipic, succinic etc at pH 2.5 and use of irradiation (Frazier and Westoff, 1988). Despite these methods of preservation, contamination of dairy products remains the order of the day before it gets to the final consumer.
1.2 Significance of the Study
Many micro-organisms have been found to be pathogenic to human consumption. Staphylococcus aureus being one of the most ubiquitous on food material such as raw meat and raw bulk milk (Matthews et al., 1997) was chosen to be studied to know the antibiotics that are most effective against Staphylococcus aureus. The knowledge of the antibiotics that are most effective can be suggested for the treatment of the cows that their meat are being sold in the market to reduce the effect of Staphylococcal infestation on cow meat and the resultant detrimental effects it has on humans when consumed.
1.3 Aims and Objectives
Various bacteria are associated with cow meat; this research is aimed at achieving the isolation of Staphylococcus aureus from cow meat sold at different locations in Gwagwalada metropolis. The specific objectives of this study include:
i. To determine the amount of Staphylococcus aureus found in cow meat in Gwagwalada market.
ii. To carry out antibiogram analysis of Staphylococcus aureus.
iii. To speculate the significance of the antibiotics used.
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