ABSTRACT
This research was carried out
for the isolation and identification of fungal spoilage organisms in foods. The
foods studied are, packaged and unpackaged powdered milk, corn flour and
soybeanflour. These samples were bought from Enugu main market (Ogbete) using
sterile nylon bags for each samples and taken to the laboratory for analysis.
One gram of each sample was put into nine (9) ml of sterile water, tenfold dilution
was carried out upto the fithth srerile test tubes to reduce microbial load.
Spread plate method was used by taking 0.1 from each dilution unto sterile
prepared Sabouraud dextrose agar plates, the plates were incubated atleast for
48hrs for growth to occur. Representative growths from the plates were then sub
cultured on agar slant to obtain pure cultures for identification. Slide
culture technique was use for proper identification of the filamentous fungiand
incubation was at least four (4) - six (6) days. Lactophenol blue was use to
stain the fungi growth on the slide and the cover slip which was viewed under the
light microscope. From this research carried out genera of fungi isolated were,
Aspergillus, Fusarium, Pennicillium
andMucor. The dominant genus isolated was Aspergillus. The most contaminated food product from this research
is the corn flour sample which was contaminated with all the fungal genera
identified. The fungi isolated are known
to be pathogens of man some species of aspergillus are known to produce toxins
which is the aflatoxin causing the diseases known as aflatoxycosis in man. Also
some species of penicillium and fusarium are known to produce mycotoxins
which causes human diseases. These food products can be contaminated due to
daily exposure to air as fungi spores are known to be present in large number
in the air making it easy for them to invade exposed foods.
CHAPTER ONE
INTRODUCTION
Food products are a rich nutrient source that can
attract both bacterial and fungal colonizers. Pitt et al (2009).As such, the food product can be regarded as an
ecological resource. Colonization with a number of food-borne microorganisms is
beneficial with respect to nutritional value and prolonged storage of the food
product, which is known as food fermentation in other case. After successful
colonization of the product, its nutritional properties are altered. Samson et al. (2004).When the nutritional value, structure, and
taste of the product are negatively influenced, this colonization is called
food spoilage. It can be accompanied by the production of toxic secondary
metabolites which may result in serious medical problems (Dijksterhuis et al.,2007). These two aspects of food colonization are two
sides of the same coin. Food spoilage is a major threat for our food stock and
is responsible for enormous losses Pitt et
al., (2009).
Fungi are the main degraders of the sturdy plant
cell wall components that otherwise would accumulate within the ecosystems of
the world. Prior to spoilage, the fungi can be present on or inside of the crop
in low numbers, or as survival structures. Spoilage fungi can also be
introduced to an empty habitat if the food is previously treated by
pasteurization treatments. Food products include two main groups, which are
living crops and processed food (Karlshøjet
al.,2007).
Colonization
of food products is hence very diverse. The relationship between the living
crop and fungi can be illustrated. Then the association of fungi with different
types of processed food is described. Preservation techniques make the food
product a difficult environment to colonize, although it is also a rich medium.
Only fungi (Springer-Verlag et al 2013) that can survive certain adverse
conditions including high osmolarity and heat can successfully spoil processed
food. Samson et al. (2004) provide overviews on the taxonomic description and specificity
of food spoilage fungi, Dijksterhuis et al (2007) highlight numerous aspects of the relation
between food and fungi including spoilage and fermentation.
AIM AND OBJECTIVES
This research is aimed at
isolating and identifying fungi spoilage organisms in packaged and unpackaged milk,
soybean flourand corn flour
OBJECTIVE
To isolate fungi spoilage
organisms associated with packaged and unpackaged powdered milk, corn flour and
soybean flour
To identify the isolated spoilage organism
associated with the samples. ================================================================
Item Type: Project Material | Attribute: 43 pages | Chapters: 1-5
Format: MS Word | Price: N3,000 | Delivery: Within 30Mins.
================================================================
No comments:
Post a Comment