Determination of Microbial Load on Smoked Fish Sold in Owerri Metropolis
Chapter One
AIM AND OBJECTIVES
This work is aimed at investigating the microbial load on smoked fish sold at Owerri Metropolis and its objectives is as stated;
- To determine the microbial load on smoked fish
- To isolate different organisms from smoked fish
- To identify them using biochemical and bacteriological test
CHAPTER TWO
LITERATURE REVIEW
BACKGROUND OF STUDY
A fish is any member of a paraphyletic group of organisms that consist of all gill-bearing aquatic craniate animals that lack limbs with digits. Included in this definition are the living hagfish, lampreys, and cartilaginous and bony fish, as well as various extinct related groups. Most fish are ectothermic (“cold-blooded”), allowing their body temperatures to vary as ambient temperatures change, though some of the large active swimmers like white shark and tuna can hold a higher core temperature (Goldman, 1997). Fish are abundant in most bodies of water. They can be found in nearly all aquatic environments, from high mountain streams (e.g., char and gudgeon) to the abyssal and even hadal depths of the deepest oceans (e.g., gulpers and anglerfish). With 33,100 described species, fish exhibit greater species diversity than any other group of vertebrates (Fish base, 2015).
Fish are an important resource for humans worldwide, especially as food. Commercial and subsistence fishers hunt fish in wild fisheries (see fishing) or farm them in ponds or in cages in the ocean (see aquaculture). They are also caught by recreational fishers, kept as pets, raised by fish keepers, and exhibited in public aquaria. Fish have had a role in culture through the ages, serving as deities, religious symbols, and as the subjects of art, books and movies.
Because the term “fish” is defined negatively, and excludes the tetrapods (i.e., the amphibians, reptiles, birds, and mammals) which descend from within the same ancestry, it is paraphyletic, and is not considered a proper grouping in systematic biology. The traditional term pisces (also ichthyes) is considered a typological, but not a phylogenetic classification (Fish base, 2015).
The earliest organisms that can be classified as fish were soft-bodied chordates that first appeared during the Cambrian period. Although they lacked a true spine, they possessed notochords which allowed them to be more agile than their invertebrate counterparts. Fish would continue to evolve through the Paleozoic era, diversifying into a wide variety of forms. Many fish of the Paleozoic developed external armor that protected them from predators. The first fish with jaws appeared in the Silurian period, after which many (such as sharks) became formidable marine predators rather than just the prey of arthropods (Fish base, 2015).
EVOLUTION OF FISH
Fish do not represent a monophyletic group, and therefore the “evolution of fish” is not studied as a single event (Lecointre and Guyader, 2007).
Early fish from the fossil record are represented by a group of small, jawless, armored fish known as ostracoderms. Jawless fish lineages are mostly extinct. An extant clade, the lampreys may approximate ancient pre-jawed fish. The first jaws are found in Placodermi fossils. The diversity of jawed vertebrates may indicate the evolutionary advantage of a jawed mouth. It is unclear if the advantage of a hinged jaw is greater biting force, improved respiration, or a combination of factors.
Fish may have evolved from a creature similar to a coral-like Sea squirt, whose larvae resemble primitive fish in important ways. The first ancestors of fish may have kept the larval form into adulthood (as some sea squirts do today), although perhaps the reverse is the case (Lecointre and Guyader, 2007).
CHAPTER THREE
MATERIALS AND METHODS
Materials: materials used are; petri dish, test tubes, pipette, macCartney bottle, morter or blender, measuring cylinder, autoclave, pressure cooker, incubator, hot air oven, weighing balance, colony counter, Bunsen burner, wax pencil, masking tape, dissecting needles, glass slide and cover slip.
Reagents: reagents used are; distilled water, crystal water stain, iodine solution, ethanol, safranin, plasma, hydrogen peroxide, Kovac’s reagent, 5% alphanaphthol, 40% KOH, lactophenol cotton blue.
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Media: used are Nutrient Agar (NA), Manitol salt agar, MacConkey agar, and Potato Dextrose Agar (PDA), Tryptone broth, Simmons citrate medium, Salmonella Shigella agar.
METHODS
STUDY AREA
The study was carried out within Owerri Municipal Council in Imo State, Nigeria. Imo State is one of the thirty six states in Nigeria. Imo State is located in the south Eastern part of Nigeria and Lies longitude 6O35’ East and 7O28 East and between latitude 5O10’ North and 5O57 North. It has a total land area of about 5,067.20km2 (ministry of land Owerri, 1992). Imo State is made up of distinct Zones namely: Okigwe, Orlu and Owerri. It is also delineated in 27 local governments Area.
CHAPTER FOUR
RESULTS
At the end of the culture, the average microbial load was determined and recorded as shown in table 3.1, below. The total heterophilic bacteria count ranges from 3.1-13.8 X106cfu/g while total fungi count ranges from 0.0-0.3X106.
CHAPTER FIVE
DISCUSSION AND CONCLUSION
DISCUSSION
This study shows that pathogenic bacteria and fungi are present in smoke Scombia scombia sold in students market and works layout market, in Imo State. According to International Commission on Microbiological Specification for Food (ICMSF, 1986), the maximum recommended bacteria count for good quality product is 5.0X105. Bacteria present in the fish samples include Bacillus spp., Staphylococcus spp., Escherichia coli, and Salmonella spp. The occurrence of Staphylococcus spp. and Escherichia coli in the smoked fish were in accordance with Martin (1994) when he stated that these organisms were the commonest microorganisms associated with smoked fish. The presence of Staphylococcus spp. in fish samples according to Okonko, et al., (2008) might have been through contamination by handling.
The bacteria group of Staphylococcus spp. according to Herman et al., (2011) reported that it was one of the most common causes of human diseases and they constitute the normal flora of human skin and mucous membrane without resulting in a diseased conditions. The bacteria class may also cause superficial and systematic infections such as boils, impetigo and follicalitis while more serious and more common infections could be pneumonia, bacteremia and other infections of the bones and wounds. Also, Escherichia coli usually cause diarrhea and kidney damage as well as complicated community acquired urinary tract infections. The fungi present in the fish samples are Yeast spp., Mucor spp., and Aspergilus spp. It was observed in the study that the presence of fungi, particularly aflatoxigenic molds produced mycotoxin, which has pathogenic effects on man; it destroys the liver and kidney failure resulting to death. The presence of the organisms could be as a result of handling during smoking and also cross contamination during storage, after smoking and handling during sales of smoked fish.
CONCLUSION
In conclusion smoked fish (Scombia scombia) from students market and works layout market were heavily contaminated with many bacteria species including members of the genera Escherichia, Staphylococcus, Bacillus, and Salmonella due to the greater unhygienic conditions of the environment. The public health concern of smoked fish (Scombia scombia) is therefore the poor handling and processing either by processors, marketers or the consumers. This has greatly contributed to the contamination of these products by various pathogenic microorganisms which makes their consumption hazardous to health.
RECOMMENDATION
Environmental sanitation education and orientation should be organized for food and processors; this will enable them to reduce the unattractiveness environment that makes their operations smelly and repulsive. The relevant national and municipal authorities must ensure improve quality of smoked fish to safe guard public health and enhance food safety in the country.
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