-
Isolation And Characterization Of Fungi Associated With “spoiled†Tomatoes
CHAPTER ONE -- [Total Page(s) 2]
Page 1 of 2
-
-
-
CHAPTER ONE
1.0 INTRODUCTION
Vegetables
constitute commercially and nutritionally important indispensable food
commodity. Vegetable naturally play a vital role in human nutrition by
supplying the necessary growth factors such as vitamins and essential
minerals in human daily diet and that can help to keep a good and normal
health. Vegetables are widely distributed in nature. One of the
limiting factors that influence the fruit economic value is the
relatively short shelf-life period caused by pathogen’s attack (Droby,
2006: Zhu, 2006).
Tomato (Lycopersiconesculentum) pronounced
Toh-MAH-to is the most important vegetable worldwide. Tomato is an
annual plant which belongs to the Solanaceaefamily which includes other
well-known species such as Potato, Tobacco, Pepper and Egg plants
(aubergine) and can reach a height of over two meters. It’s a berry
fruit, tomato is grown mainly in soil (Frazier and Westhoff,2004).
Tomato
is essential mainly for its dietary needs and can be consumed in
diverse ways. It can be cooked as vegetable, as an ingredient in many
dishes and sauces; in the making of stew, fruit juices and can be eaten
raw in salads(Masefield et al., 2002).
The modern day tomatowhich is a
very popular fruitoriginated from South-Western Hemisphere, now the
Peru-Euador area(Rick,2001).From here,it was distributed to many parts
of tropical America. It possibly arrived the West African Ports via
Portuguese traders or the Sudan (Tindall, 2004).
Tomato in West
Africa is grown in gardens and irrigation schemes. In Nigeria, most
tomatoes are grown in the northern parts of the country(Erinle,2007) and
there is no record of any systematic or organized traditional storage
method for vegetables and fruits. They are usually sold immediately
after harvesting. They are packed in baskets, cardboard boxes, or wooden
crates ready for transportation to the markets.
Tomato is the most
perishable vegetable during handling, transportation and storage. This
is because tomato contains large amount of water which makes them
susceptible to spoilage by the action of microorganisms such as fungi,
bacteria and protozoans (Ross, 1975). Estimates have shown that about
one third of the produce is lost before reaching the consumer (Erinle,
2007), this loss has been attributed to a number of factors which
include physical (mechanical breakage, bruises), physiological and also
damages caused by pathological agents (Thompson and Kelly, 2000), market
value of the tomato are mainly reduced by this factors.
Watt and
Merrill, (2000) defined spoiled food as that which have been damaged or
injured so as to render it undesirable for human consumption. Various
activities may result in food spoilage: insect activities,causing
physical injuries for example, bruisingand enzyme activity by
microorganism causes change in colour, taste, smell, texture and quality
of the food.
Pauland Sarisbury, (1981) also referred to spoilage as
any change in the condition of food in which the food becomes less
palatable or even toxic: these changes may be accompanied by alteration
in taste, smell, appearance or texture.
The spoilage of food by
microorganisms should not be viewed as a sinister plot on the part of
the microbes deliberately to destroy foods but as a normal function of
these organisms in the total ecology of all living organisms (Watt and
Merrill, 2000). It has also been estimated by Watt and Merrill (2000)
that 20% of all fruits and vegetables harvested for human consumption
are lost through microbial spoilage causing one or more of 250 market
diseases. Spoilage of fresh tomato usually occurs during storage and
transit and also while waiting to be processed.
Frazier and
Westhoff,(2004) reported that fruits and vegetables after picking
continue to respire and as a result heat is produced, this heat is known
as ‘vital heat’, the amount which varies with particular amount of
fruits and vegetables.
Vegetables that respire more thereby
generating most heat are those that perish/spoil most rapidly (Wheeler,
2005). The resulting respiration of the fruits in addition to the normal
ripening process complicates an independent discussion on
microbiological spoilage of fruits in general and tomato in particular.
CHAPTER ONE -- [Total Page(s) 2]
Page 1 of 2
-
-
ABSRACT - [ Total Page(s): 1 ]The study examined the various fungal pathogens associated with tomatoes spoilage as well as their preliminary taxonomic grouping up to genus level. 25 samples of the spoiled tomatoes were collected from five locations within Gwagwalada area council. Locations include: Passo Village, Gwagwalada market, Phase III, New Kutunku and Dagiri. Thesame prevalence rate(100%) was recorded for all tomato samples purchased in all locations.The level of awareness of the general public in regards to the spoil ... Continue reading---
