Assessing Toxins in Stored Grains

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ASSESSMENT OF TOXINS PRODUCING FUNGI IN STORED GRAINS (RICE,
BEANS, WHEAT, GROUNDNUT)
BY
EGWUASIM, MIRACLE CHIDERA
REG NO. 2017030181745
SUBMITTED TO THE
DEPARTMENT OF APPLIED MICROBIOLOGY AND BREWING
FACULTY OF APPLIED NATURAL SCIENCES
ENUGU STATE UNIVERSITY OF SCIENCE AND
TECHNOLOGY (ESUT)
MAY, 2022

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DECLARATION
I, EGWUASIM MIRACLE CHIDERA with Reg No, 2017030181745, do hereby declare
that the work embodied in this report is original and is the true record of my research work. It
has not been submitted either in full or in part (except in the acknowledged reference) for any
other diploma or degree of this or any other university.
EGWUASIM MIRACLE CHIDERA ___________________________
Signature/Date

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APPROVAL PAGE
This project has been approved for the Award of the Degree of Bachelor of Science in Applied
Microbiology and Brewing, Enugu State University of Science and Technology (ESUT).
BY
Prof F.O. Tasie _________________________
(Supervisor) Signature/Date
Dr. V.O. Aniaku _________________________
(Head of Department) Signature/Date
Prof. M.U. Orji __________________________
External Examiner Signature/Date

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CERTIFICATION
We hereby certify that this research work ‘," was carried out and compiled under constant
supervision, by Egwuasim Miracle Chidera with matriculation number 2017030181745 and
submitted to the Department of Applied Microbiology and Brewing in partial fulfillment of
requirements for the award of the degree of Bachelor of Science in Applied Micro biology and
Brewing, Enugu State University of Science and Technology, Enugu State meets the regulatory
standards thereof and is hence approved for its Contribution to knowledge and literary
presentation.
______________________
Prof. F.O. Tasie

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DEDICATION
I dedicate this project to God Almighty for His grace and to my parents Mr. and Mrs. Iheanyi
Egwuasim and my brother Iheanyi Darlington Egwuasim.

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ACKNOWLEDGEMENTS
I wish to specially give thanks to God Almighty for His love, mercy, grace, provision and
strength throughout my period of study.
My profound gratitude also goes to Dr. Mrs. C.C. Ugwu, Prof. F.O. Tasie, Mr. Darlington, and
my lovely parents for their support throughout his programme, you are indeed lovely.
Also my heart of gratitude goes to my project supervisor Prof F.O Tasie and HOD Dr. V.O
Aniaku, and other lecturers in Applied Microbiology and Brewing Department for their
immeasurable contribution throughout this project.
Finally, I wish to acknowledge my class mates, Miss Answer, Miss Miracle, Sandra, Ndubisi,
GodsTreasure, Agu Samuel Uzoma, Mba Immaculate, Ambrose Judith, Ogbonna Izuchukwu.
I also appreciate those who could not be mentioned due to space constraint. The Lord bless
you.

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ABSTRACT
Cereals and legumes are important food crops and provide cheap source of energy and protein,
and therefore, are good substitutes or supplements to major staple foods and help meet the
needs of Africa’s teeming population. Five products (rice, wheat, groundnut, and beans) stored
for 2 – 4 months in different packaging materials were assessed for the presence of mycotoxin
producing moulds. These samples were randomly selected from different market. The
organisms were isolated using ten-fold serial dilution and cultured appropriate dilutions using
pour plate technique. The frequently occurring moulds species identified were Aspergillus
flavus, Aspergillus Niger, Aspergillus fumigatus and Penicillium chysogenum. The occurrence
of high contamination levels of Aspergillus species indicates the possible production of
aflatoxin in stored food products. The contamination of such products by fungi should be a
source of worry and necessities the need for proper personal and environmental hygiene in the
processing of cereals.

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CHAPTER ONE
1.0 INTRODUCTION
Fungi are subdivision of the subkingdom Thallophyta. They have a well-defined nucleus but
lack the chlorophyll which is a characteristic of most other plant. They also lack vascular tissue
but made up of an assimilate body which may be amoeboid or unicellular in some species, but
typically are made up of multicellular branding filaments called hyphae reproducing asexually
by the means of spores. They are heterotrophs feeding on substrates of plants and animals.
(African Journal of Microbiology Research Vol. 5(25), 2011).
Many fungi are pathogens of plants grown for food, while as smaller numbers are agents of
diseases in animals including man. They attack and destroy raw and manufactured products
resulting in great economic loss.
Fungi do not only cause direct losses but can threaten the health of both man and animals by
producing poisons, so called mycotoxins, which contaminates food & feed.
Mycotoxins are secondary fungal metabolites that contaminate agricultural commodities and
can cause sickness or death in human and animals. Toxins are extremely heat stable and resist
ultraviolent light inactivation. (African Journal of Microbiology Research Vol. 5(25), 2011).
Diseases caused by mycotoxins are called mycotoxicoses. Toxins can be acutely or chronically
toxic or both depending on the kind of toxin and dose.
They are mainly produced by the genus Aspergillus sp., Penicillium sp. Fusgrium, Alternaria,
hemin thosporium, gyreophora, phoma & zygosporium. It usually proliferate grains (wheat,
rice, beans, groundnut), toxigenic fungi contaminating agricultural grains have been
conventionally divided into two groups, the “field fungi” and the “storage fungi”
(i) Field fungi: invade seed crops during plant development e.g. (ladosporium,
fusarium & alternanria spp. Also a sharp distinction is not possible as fungi growth
may start in the field & during storage.
The original source of fungi is in the field.
(ii) Storage fungi: include all species of Aspergillus sp., fusarium & Penicciliium spp.
Toxins can cause a variety of adverse health effect and pose a serious health threat
to both human & live stock. (African Journal of Microbiology Research Vol. 5(25),
2011)
The growth of fungi ins storage is governed by the following factors
(i) Composition of nutrients in the grain
(ii) Moisture of temperature conditions

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A cereal is any grass cultivated for the edible component of its grains (botanically, it is called
caryopsis). Cereal grains are grown in a greater quantity and provide more food energy. It is
rich in the source of vitamin, mineral, carbohydrate, fats and oil, protein.
In some developing countries, grains in the form of rice, groundnut, beans, wheat constitute a
majority of daily sustenance. Consumption is moderate.
Toxin can cause death or chronic health resulting from damage to the kidneys and liver. It can
damage immune, cardiovascular, endocrine, reproductive and nervous system.
Toxins are the cause of concern in grain storage being one of the many important factors as
they come from fungi development due to previously existing conditions such as: moisture
content, temperature, storage period contamination rate, broken grain & impurities insect
presence, oxygen rate, damage during harvest process and grains seed transport.
Cereal crops will continue to be affected by diseases as no breeding program can develop
cultivars with acceptable levels of resistance to all diseases under all conditions. Emphasis on
resistance is expected to increase as fungicide use and residues become less acceptable.
(African Journal of Microbiology Research Vol. 5(25), 2011)

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CHAPTER TWO
LITERATURE REVIEW
2.1 GRAINS AND EXAMPLES
2.1.1 RICE
Rice is the seed of the grass species Oryza sativa (Asian rice) or less commonly Oryza
glaberrima (African rice). The name wild rice is usually used for species of the genera Zizania
and Porteresia, both wild and domesticated, although the term may also be used for primitive
or uncultivated varieties of Oryza. As a cereal grain, domesticated rice is the most widely
consumed staple food for over half of the world's human population, especially in Asia and
Africa. It is the agricultural commodity with the third-highest worldwide production, after
sugarcane and maize. Since sizable portions of sugarcane and maize crops are used for purposes
other than human consumption, rice is the most important food crop with regard to human
nutrition and caloric intake, providing more than one-fifth of the calories consumed worldwide
by humans.
There are many varieties of rice and culinary preferences tend to vary regionally.
The traditional method for cultivating rice is flooding the fields while, or after, setting the
young seedlings. This simple method requires sound irrigation planning but reduces the growth
of less robust weed and pest plants that have no submerged growth state, and deters vermin.
While flooding is not mandatory for the cultivation of rice, all other methods of irrigation
require higher effort in weed and pest control during growth periods and a different approach
for fertilizing the soil.
(https://en.m.wikipedia.org/wiki/list_of_rice_diseases)
2.1.2 BEAN
A bean is the seed of one of several genera of the flowering plant family Fabaceae, which are
used as vegetables for human or animal food. They can be cooked in many different ways,
including boiling, frying, and baking, and are used in many traditional dishes throughout the
world. (https://en.m.wikipedia.org/wiki/list_of_rice_diseases)
The word "bean" and its Germanic cognates (e.g. German Bohne) have existed in common use
in West Germanic languages since before the 12th century, referring to broad beans, chickpeas,
and other pod-borne seeds. This was long before the New World genus Phaseolus was known

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in Europe. After Columbian-era contact between Europe and the Americas, use of the word
was extended to pod-borne seeds of Phaseolus, such as the common bean and the runner bean,
and the related genus Vigna. The term has long been applied generally to many other seeds of
similar form, such as Old World soybeans, peas, other vetches, and lupins, and even to those
with slighter resemblances, such as coffee beans, vanilla beans, castor beans, and cocoa beans.
Thus the term "bean" in general usage can refer to a host of different species.
Seeds called "beans" are often included among the crops called "pulses" (legumes), although
the words are not always interchangeable (usage varies by plant variety and by region). Both
terms, beans and pulses, are usually reserved for grain crops and thus exclude those legumes
that have tiny seeds and are used exclusively for non-grain purposes (forage, hay, and silage),
such as clover and alfalfa. The United Nations Food and Agriculture Organization defines
"BEANS, DRY" (item code 176) as applicable only to species of Phaseolus. This is one of
various examples of how narrower word senses enforced in trade regulations or botany often
coexist in natural language with broader senses in culinary use and general use; other common
examples are the narrow sense of the word nut and the broader sense of the word nut, and the
fact that tomatoes are fruit, botanically speaking, but are often treated as vegetables in culinary
and general usage. (https://www.britannica.com)
2.1.3 WHEAT
Wheat is a grass widely cultivated for its seed, a cereal grain which is a worldwide staple food.
The many species of wheat together make up the genus Triticum; the most widely grown is
common wheat (T. aestivum). The archaeological record suggests that wheat was first
cultivated in the regions of the Fertile Crescent around 9600 BCE. Botanically, the wheat kernel
is a type of fruit called a caryopsis. (https://www.mlsu.ac.in/econtents/260_SEC-
Unit%202%20cereals.pdf)
2.1.4 GROUNDNUT
The peanut, also known as the groundnut, goober, pindar or monkey nut (UK), and
taxonomically classified as Arachis hypogaea, is a legume crop grown mainly for its edible
seeds. It is widely grown in the tropics and subtropics, being important to both small and large
commercial producers. It is classified as both a grain legume and, due to its high oil content,
an oil crop. World annual production of shelled peanuts was 44 million tons in 2016, led by
China with 38% of the world total. Atypically among legume crop plants, peanut pods develop

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underground (geocarpy) rather than above ground. With this characteristic in mind, the botanist
Carl Linnaeus gave peanuts the specific epithet hypogaea, which means "under the earth".
The peanut belongs to the botanical family Fabaceae (or Leguminosae), commonly known as
the legume, bean, or pea family. Like most other legumes, peanuts harbor symbiotic nitrogen-
fixing bacteria in root nodules. The capacity to fix nitrogen means peanuts require less
nitrogen-containing fertilizer and improve soil fertility, making them valuable in crop rotations.
Peanuts are similar in taste and nutritional profile to tree nuts such as walnuts and almonds,
and, as a culinary nut, are often served in similar ways in Western cuisines. The botanical
definition of a nut is "a fruit whose ovary wall becomes hard at maturity". Using this criterion,
the peanut is not a nut. However, peanuts are usually categorized as nuts for culinary purposes
and in common English more generally. (peanut-Wikipedia.org)
2.2 PESTS AND DISEASES IN GRAINS
2.2.1 Fungi Infections/Diseases in Rice
Fungi Diseases
Aggregate sheath Ceratobasidium oryzae-sativae
Rhizoctonia oryzae-sativae [anamorph]
Black horse riding Curvularia lunata
Cochliobolus lunatus [teleomorph]
Blast (leaf, neck [rotten neck], nodal and
collar)
Pyricularia grisea
= Pyricularia oryzae
Magnaporthe grisea [teleomorph]
Brown spot Cochliobolus miyabeanus
Bipolaris oryzae [anamorph]
Crown sheath rot Gaeumannomyces graminis
Table 2.1: Showing Fungi diseases in Rice
Source: https://en.m.wikipedia.org/wiki/list_of_rice_diseases
2.2.2 Fungi infections in Beans
Anthracnose
Symptoms
Symptoms of anthracnose can appear on any plant part, although initial symptoms may appear
on cotyledonary leaves as small, dark brown to black lesions. The infected tissues manifest
minute rust-colored specks, it gradually enlarge longitudinally and form sunken lesions or eye

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spots that reach the hypocotyl of the young seedling, causing it to rot off.
(https://cropfenebank.sgrp.cigar.org)
Rhizoctonia root rot
Symptoms
Rhizoctonia solani may induce seed rot, damping-off, stem canker, root rot, and pod rot.
Rhizoctonia can infect seeds before germination, resulting in seed decay. Lesions on a young
seedling expand rapidly and result in damping-off. Seed and seedling infection reduce seedling
establishing and therefore lower plant densities often severely enough to be visually
https://cropfenebank.sgrp.cigar.org
Fusarium root rot
Symptoms
Initial symptoms of fusarium root rot appear as longitudinal, narrow, reddish lesions or streaks
on the hypocotyl and primary root about one or two weeks after seedling emergence. As
infection
progresses, lesions become numerous, coalesce, and the entire underground stem and root
system may become covered with reddish brown superficial lesions. The discoloration may
extend to the soil surface, but rarely beyond. The lesions have not definite margins and may be
accompanied by longitudinal fissures https://cropfenebank.sgrp.cigar.org
Fusarium yellows
Symptoms
The Fusarium yellows pathogen is morphologically similar to all the members of the species
F. oxysporum. However, it is recognized by its physiological and pathological adaptation to
beans, hence the interspecific taxa designation f. sp. (formae speciales) phaseoli. Initial
symptoms appear on lower leaves which exhibit yellowing and wilting. These symptoms may
be confused with those caused by phosphorous deficiency. This yellowing and wilting becomes
more pronounced and progress upward into younger leaves. Stunting may also become evident,
especially if plant infection occurred during the seedling state.

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Southern blight
Symptoms
The infectious process can result in damping-off, stem blight, and root rot. Initial symptoms on
infected plants appear as dark-brown water-soaked lesions on the lower stem surface area just
below the soil line. These lesions extend downward, through stem tissue and so start root-rot
symptoms. Under moist conditions, lesions on the stem tissue continue to progress downward
and eventually may kill the entire root system Other symptoms consist of leaf yellowing and
defoliation of the upper plant branches which may be followed by a sudden wilt condition.
Abundant white coarse mycelium and sclerotia and soil particles are often found attached to
stem tissue near the line soil. https://cropfenebank.sgrp.cigar.org
2.2.3 Bacteria Infection in Beans
Bacteria Wilt in Beans
Under ideal conditions, beans are an easy, proli c crop for the home gardener. However, beans
are susceptible to a number of diseases. Bacterial wilt or blight in bean plants is one such
disease. Advanced cases can decimate a crop. Are there any bacterial wilt treatments or, at the
very least, is there any method for control of bacterial wilt?
Bacterial wilt of dry beans is caused by Curtobacterium accumfaciens pv. Flaccumfaciens.
Both bacterial wilt and bacterial blight in bean plants are fostered by moderate to warm
temperature, moisture, and plant wounds both during and post- owering. The bacterium affects
many types of beans including:
 Soybeans
 Hyacinth beans
 Runner beans
 Limas
 Peas
 Adzuki beans
 Mung beans
 Cowpeas
The rst symptoms of bacterial wilt in beans appear in the leaves. Hot, dry weather is often
enough to trigger an explosion in the growth of the bacteria. It infects the vascular system of
the beans, impeding water movement. Young seedlings wilt as well as the leaves of older
plants. Irregular lesions also appear on the leaves and eventually drop.

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Pods may also have evidence of infection and seeds may become discolored. Infection during
the initial growth phase can stunt or kill seedlings.
The bacterium survives in infected debris and is also seed borne, making it difficult to treat. So
how can you control bacterial wilt?
Bacterial Wilt Treatment
This particular pathogen is a tough cookie. It can overwinter in infected bean debris and even
on the debris of other crops that have been rotated in following a bean crop. The bacterium can
still be viable after two years. It is spread from the debris by wind, rain, and irrigation water.
This bacterial pathogen can be managed, but not eliminated, through crop rotation, sanitation,
sowing only treated certified seeds, varietal selection, and avoiding stress and excessive
moisture on foliage.
 Rotate crops for three to four years with a bean crop in the third or fourth year only; plant
corn, veggies, or small grain crops during the rotation period.
 Practice sanitation of not only bean debris, but removal of any volunteer beans and
incorporation of straw into the soil.
 Sanitize tools and storage containers that may have been associated with the beans, as they
may also harbor the pathogen.
 Only plant certified seeds. This will lessen the possibility of infection, although the pathogen
can still be imported from an external source.
 Plant resistant varieties. Heirlooms and other older bean varieties, like pinto or red kidney,
are susceptible to the disease. There are newer varieties currently available that are more
resistant to bacterial infections.
 Don’t work among the beans when they are wet. Also, avoid irrigation via sprinklers which
can spread the disease.
A copper based bactericide may reduce infection of bacterial blight and bacterial wilt in bean
plants but it will not eradicate it. Apply the copper spray in the early growing season, every
seven to ten days to reduce the number of pathogens.
2.2.4 Fusarium infection in wheat, aggressiveness and changes in grain quality
Fusarium Head Blight (FHB) Severe epidemics worldwide, altering yield and quality
parameters of grains and contaminating them with fungal toxins. The aggressiveness of
Fusarium spp. could be ascribed to different mechanisms, such as the production and release
of extracellular plant-cell-wall degrading enzymes and proteases which are crucial in the

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processes of fungal colonization. We use cookies to make sure that our website works properly,
as well as some "optional" cookies to personalize and disease establishment. Once infection is
established, mycotoxins are released, and the content and advertising, provide social media
features and analyze how people use our site. By accepting some interfere with the metabolism
of the host. Wheat grains damaged by or all optional cookies you give consent to the processing
of your personal data, including transfer to third parties, Fusarium graminearum present
changes in their cell structure and in the composition of carbohydrate, protein and some in
countries outside of the European Economic Area that do not offer the same data protection
standards starch granules of the endosperm, which modify their physical and chemical
properties, as the country where you live. You can decide which optional cookies to accept by
clicking on "Manage Settings", altering the desired quality characteristics for baked goods. The
protein where you can also find more information about how your personal data is processed.
One of the main determinants of its commercial value since the industrial quality of the grain
depends on the concentration and type of its proteins. To evaluate the quality and end use of
flour, laboratories and industries use different techniques to analyze its protein content. Since
yield and quality of wheat grains depend on the genetic of cultivars, environment and level of
infection in the harvested grains, this review focuses on the main events related to the
infection by Fusarium and the evaluation of the disease from grains and flour. Special attention
to changes in the protein fraction are discusses, due to its direct relationship with the
commercial value.
2.2.5 Common Diseases in groundnut
Category: Fungal
Botrytis blight Botrytis cinerea
Symptoms
Numerous spots on upper surface of leaflets; entire plant or discrete parts may wilt and die;
pods and stems become covered in fungal sclerotia.
Cause
Fungus
Comments
Disease emergence favors high moisture and high temperature; plants damaged by frost or
other pathogens are particularly vulnerable to attack.

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Management
Avoiding frost damage by planting early peanut varieties can help protect the plant from fungal
colonization; application of appropriate foliar fungicides (e.g. benomyl), where available, can
help to control the disease. (https://plantvillage.psu.edu/topics/beans/infos)
Charcoal rot Macrophomina phaseolina
Symptoms
Water soaked lesions on stems of seedlings close to soil line; lesions girdle stem and kill
seedlings; lesions in similar area may be present in older plants; lesions are initially water-
soaked but turn brown; if lesions girdle the stem, plant wilts and branches die; infections
beginning in the roots cause leaves to turn yellow and wilt and causes stems to be blighted.
(https://plantvillage.psu.edu/topics/beans/infos)
Cause
Fungus
Comments
Fungus survives in crop debris in the soil; disease emergence is favored by high soil
temperatures which cause plants to be water stressed and more susceptible to disease; fungus
can survive for prolonged periods in dry soils but are killed in wet soil.
Management
Rotating crop with rice for a period of 3-4 years can reduce the level of oioculum in the soil;
providing the plants with adequate irrigation and fertilization reduces susceptibility to the
disease; there are currently no resistant varieties of peanut; frequent irrigation to wet soil
reduces the incidence of the disease.

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Cylindrocladium black rot
Cylindrocladium crotalariae
Symptoms
Leaves on main stem turning chlorotic and wilting; entire plant wilts very rapidly when there
is a period of water stress following high moisture; clusters of red-brown fungal bodies occur
on on stems, pegs and pods; roots destroyed; roots blackened and shriveled.
Cause
Fungus
Comments
Crops planted early are more susceptible to the disease as they are often exposed to cooler
temperatures and higher soil moisture; disease is seed transmitted and also can spread over long
distances by wind.
Management
The most effective method to control the disease is to plant peanut varieties that have some
resistance to the disease; rotation of crop with nonhost such as corn , cotton or tobacco may
help to reduce inoculum in the soil; application of appropriate soil fumigants in heavily infested
fields can help to control the disease. (https://plantvillage.psu.edu/topics/beans/infos)
Early leaf spot Cercospora arachidicola
Symptoms
Small chlorotic ecks on leaf petioles, stems and pegs which enlarge and turn dark in color;
lesions on upper surface of leaves usually possess a yellow halo and are reddish brown on the
underside of leaves. (https://plantvillage.psu.edu/topics/beans/infos)
Cause
Fungus
Comments
Disease emergence is favored by high humidity and warm temperatures; spread of the disease
is promoted by pronlonged leaf wetness.
Management
If disease is present, a rotation away from peanut for a period of 2-3 years is advised but is
insufficient to control the disease completely; peanut crop debris should be plowed into soil
after harvest and any volunteers removed from the nonhost crop; fungicides should be applied
with caution as they can exacerbate other foliar diseases where they are present.

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Late leaf spot Cercospora personatum
Symptoms
Small chlorotic decks on leaf petioles, stems and pegs which enlarge and turn dark in color;
symptoms may be very similar or identical to early leaf spot and can only be differentiated by
examination of conidia under a microscope.
Cause
Fungus
Comments
Disease emergence is favored by high humidity and warm temperatures; spread of the disease
is promoted by pronlonged leaf wetness.
Management
If disease is present, a rotation away from peanut for a period of 2-3 years is advised but is
insufficient to control the disease completely; peanut crop depris should be plowed into soil
after harvest and any volunteers removed from the nonhost crop; fungicides should be applied
with caution as they can exacerbate other foliar diseases where they are present.
Phyllostica leaf spot Phyllostica arachidis-hypogaea
Symptoms
Circular lesions with red-brown margins and light brown or tan centers on leaves; centers of
lesions may dry out and drop from leaf resulting in a "shot-hole" appearance.
Cause
Fungus
Comments
Phyllostica leaf spot is known to occur in the U.S., India, China, Argentina, Thailand, the
Philippenes, Pakistan, Zimbabwe, Niger and Burkino Faso.
Management
Disease is held in check by fungicides applied to control early or late leaf spot.

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Rust Puccinia arachidis
Symptoms
Characteristic orange pustules on undersides of leaves which become covered in masses of red-
brown spores; pustules may form on pods.
Cause
Fungus
Comments
Peanut rust is highly specific to peanut; disease emergence and spread is favored by warm
temperatures followed by leaf wetness.
Management
Allow field to fallow for at least one month between successive peanut plantings; remove any
volunteer peanut plants during fallowing to reduce inoculum; sprays of appropriate fungicides
such as Bordeaux mixture can effectively control the disease; such fungicides are often also
effective at controlling leaf spot. (https://plantvillage.psu.edu/topics/beans/infos)
Sclerotinia blight Sclerotinia minor
Symptoms
Tips of infected branches wilt or ag rapidly; early signs of infection include the presence of
small water-soaked lesions at the base of the stems which turn yellow or bleached; leaves on
infected branches turn chlorotic and then wither; uffy white fungal growth may appear on
infected tissues during periods of high humidity.
Cause
Fungus
Comments
Fungus can survive for prolonged periods in the soil, even in the absence of peanut; emergence
of the disease in the peanut crop is favored by periods of cool weather, moist soil and high
humidity.
Management
Plant seeds which are coated with protectants; avoid injuring plants with tools and/or
machinery; application of appropriate fungicides can reduce crop losses when disease is
present; avoid excessive irrigation during cool weather.

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2.3 HARVESTING AND STORAGE
2.3.1 Harvesting of Rice
Harvesting is the process of collecting the mature rice crop from the field. Paddy harvesting
activities include reaping, stacking, handling, threshing, cleaning, and hauling. These can be
done individually or a combine harvester can be used to perform the operations simultaneously.
(http://www.knowledgebank.irri.org/training/fact-sheets/ite//harvesting-fact-sheet)
It is important to apply good harvesting methods to be able to maximize grain yield, and
minimize grain damage and quality deterioration.
Harvesting rice consists of the basic operations which can be done in individual steps or in
combination using a combine harvester. These include:
1. Reaping - cutting the mature panicles and straw above ground
2. Threshing - separating the paddy grain from the rest of cut crop
3. Cleaning - removing immature, unfilled, non-grain materials
4. Hauling - moving the cut crop to the threshing location
5. Field drying - leaving the cut crop in the field and exposing it to the sun for drying
(optional)
6. Stacking/piling - temporarily storing the harvested crop in stacks or piles (optional)
7. Bagging - putting the threshed grain in bags for transport and storage
Traditional harvesting activities such as field drying and stacking/piling are not recommended
because they can lead to rapid quality deterioration and increased harvest losses.
Besides these, a variety of other activities can be included in harvesting such as gathering,
reaping (gathering standing grain by cutting), bundling, and various forms of transporting the
crop and grain. (http://www.knowledgebank.irri.org/training/fact-sheets/ite//harvesting-fact-
sheet)
2.3.1.1 Storage of Rice
The purpose of any grain storage facility is to provide safe storage conditions for the grain in
order to prevent grain loss caused by adverse weather, moisture, rodents, birds, insects and
micro-organisms like fungi.
In general, it is recommended that rice for food purposes be stored in paddy form rather than
milled rice as the husk provides some protection against insects and helps prevent quality
deterioration.

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However, when rice can be stored as brown rice, 20% less storage capacity will be needed.
Brown rice is rice grain with its hulls removed but not polished. Under tropical conditions
brown rice has a very short shelf life, approximately two weeks.
Storage systems
Guidelines for safe storage
Rice storage facilities take many forms depending on the quantity of grain to be stored, the
purpose of storage, and the location of the store.
Storage systems can be through bag, bulk, or hermetic containers.
- Bag storage- grain is stored in 40−80 kg bags made from either jute or woven plastic
- Bulk storage - grain is stored in bulk at the farm or at commercial collection houses
Hermetic storage - grain is stored in an airtight container so that that moisture content of the
stored grain will remain the same as when it was sealed. These storages can extend germination
life of seeds, control insect grain pests, and improve headrice recovery.
2.3.2 Harvesting and Storage of Beans
Your bean harvest time will depend on what you plan to do with the beans after picking.
1. Snap beans or green beans harvest: Green beans are ready for harvest when they are
about the size of pencil. The seeds inside will be just visible–they’ll look like small bumps.
Depending on the variety you have planted, snap beans will be ready for picking 50 to 65
days after planting. For a big harvest, pick green beans every day or at least every couple
of days. If you allow beans to mature, the plant will stop producing new beans. So pick
regularly for an extended harvest. Pinch of cut off beans; be careful not to pull beans or you
may uproot the whole plant. Aging pods will turn yellow and leathery; streaked pods are
mealy inside. (https://harvestobale.com>Beans _harvest and storage, 2022)
2. Green beans storage: If you can’t keep up with the snap bean harvest at the table, you can
freeze or pickle green beans. To freeze green beans, wash the beans and snap off the ends.
Cut the beans into 1 inch pieces or slice lengthwise. Blanch the beans for 2 to 3 minutes.
Chill. Pack in freezer bags. (To blanch beans, add 1½ to 2 inches of water to the kettle and
heat to boiling. Place the colander with beans into the kettle and heat through 2 to 3
minutes.)
3. Shell beans harvest: Beans for shelling are picked when the seeds reach full size but are
still tender. Pick shell beans when the pods are still green and the swollen seeds are visible
from the outside. Shell beans are usually ready for harvest 66 to 75 days after planting.

23 | P a g e
Like snap beans, keep picking shell beans and the plant will keep producing; don’t allow
the pods to yellow.
4. Shell beans storage: Shelled beans can be steamed, baked, and boiled for fresh eating.
Shell beans also can be frozen: wash the beans and shell them. Blanch shelled beans for 2
to 3 minutes, depending on the size of the bean. Chill. Pack in freezer bags. (To blanch
beans, add 1½ to 2 inches of water to the kettle and heat to boiling. Place the colander with
beans into the kettle and heat through 2 to 3 minutes.)
5. Dry beans harvest: Dry beans stay on the plant until the seeds are hard and rattle in the
pods. The alternative is to cut the plants when pods turn yellow and hang the plants in a
warm dry place until the pods become brittle and the seeds rattle in the pods. It’s best to
harvest dry beans before the pods spilt open and the beans spill out. Dry beans are ready
for harvest 90 to 100 days after planting. If the weather forecast calls for rain or frost, pull
up the bean plants and dry them indoors. (Pick the pods off of pole beans which are too big
to pull up whole. Dry pods on screens or racks indoors.)
6. Dry bean storage: Store dry beans in airtight jars. Be sure the beans are dry before storing
them. To absorb moisture left in beans during storage, place a tablespoon of powdered milk
in a folded paper towel inside each jar of dried beans. (https://harvestobale.com>Beans
_harvest and storage, 2022).
2.3.3 Harvesting and Storage of Wheat
Losses of wheat due to inadequate storage and other post-harvest factors at the farm, village
and commercial levels of up to 4 percent have been observed (McFarlane, 2019; Abdullahi and
Haile, 2012), though losses in excess of 40 percent for other cereals are not uncommon (NRC,
2016). Deterioration of stored grain is influenced by physical (temperature, humidity),
biological (microflora, arthropod, vertebrate) and technical (storage conditions, methods and
duration) factors. Experience has shown that such losses are not easily reduced in the absence
of well-integrated policies and plans to develop the total system of production, marketing,
storage and distribution (Tyler and Boxall, 2014).
Food storage pests seem to have been associated with grain stores since time immemorial.
Storage pests have been identified in grain stores found in the tomb of Tut'ankhamun (1345
BC) and other ancient sites (Buckland, 2018). So too, the discussion of proper grain storage
techniques is not a contemporary issue. The ancient scholars Aristotle, Pliny and Vergil offered
observations and recommendations of grain storage techniques, including the use of seed
dressings of olive oil to kill infesting insects (Panagiotakopulu and Buckland, 2021).

24 | P a g e
2.3.4 Harvesting and Storage of Groundnut
Arachis hypogaea (L.), commonly known as groundnut or peanut, is an important oil, food and
feed legume crop originally from South America (Hammons, 2014). It is a valuable food crop
because of its high oil content (43-55%) and protein content (25-28%), and provides vitamins
and minerals for millions of households (Reddy et al., 2013). In addition, after oil extraction,
the residual groundnut cake is processed into animal feed. Groundnut is now widely grown
throughout the tropical, sub-tropical and warm temperate areas in Asia, Africa, Oceania, North
and South America, and Europe (Freeman et al., 2019). Groundnut was introduced to West
Africa by Portuguese explorers in the 16th century (Hammons, 2012). Niger, which produces
about 453,577 tons per year (FAO, 2016), is ranked 7th among the major groundnut producers
in Africa after Nigeria, Sudan, Chad, Cameroon, Senegal, and Tanzania. However, in 2016,
groundnut productivity in Niger (588.2 kg ha-1) was low
compared to leading producers in West Africa, e.g., Nigeria (1,130 kg ha-1) and Senegal (817
kg ha-1) (FAOSTAT, 2016).
In Niger, groundnut is the second most important legume crop after cowpea (Vigna unguiculata
L. Walp) (Hampson et al., 2014). Thus, groundnut in Niger plays a major role in local, regional
and international/export markets. Exports from Niger to Europe began in 1885 with nearly two-
thirds of Nigerien farmers producing groundnut in the 1930s thanks to the incentive prices
offered by European markets (Rashkov, 2013). Based on FAO (2016), Niger’s production of
unshelled nuts has increased from 147,000 MT in 2007 to more than 450,000 MT in 2016.
Most of this increase in yield is due to adding more land into groundnut production together
with limited yield increases. Niger’s groundnut production and yields have been affected over
the years by low performing varieties, drought, pest attacks and low prices linked to the entry
of soybeans into the world market of oil seed crops (Ntare et al., 2015; Ndjeunga et al., 2016;
Coulibaly et al., 2017). A large proportion of the Niger production (75 %) comes from the
regions of Maradi and Zinder (M.A., 2018).
Field pests are one of the major challenges affecting groundnut production. There are several
species of groundnut field insect pests which are responsible for substantial yield losses
(Biswas, 2014). Among these pests are aphids that are vectors of the rosette which is the most
destructive virus disease of groundnut (Naidu et al., 2016; Waliyar et al., 2017). In addition to
preharvest contraints, there are several challenges associated with groundnut postharvest
management practices. These challenges are linked to poor drying and storage that result in
microbial contamination, and pest (insect, rodent, etc.) attacks. Postharvest losses due to pests
and poor management practices can reach up to 70% after six months of storage (Oaya et al.,

25 | P a g e
2012). Other groundnut postharvest challenges include grain biochemical changes (flavor
change, rancidity, viability loss), physical changes (shrinkage and weight loss), and absorption
of odors and chemicals during storage. Poor postharvest
management practices not only increase losses, but also reduce the quality and value of the
groundnuts and hence access to market. Baidu-Forson et al. (1997) noted that farmers’ access
to markets for unshelled groundnut was an important challenge that required intervention in
Niger.
In view of these pre- and post-harvest challenges to developing the groundnut value chain in
Niger, a study was conducted to assess farmers’ constraints and opportunities to improve
production and marketing. Increased groundnut production and access to markets will increase
food security and income of farmers in Niger. Our main objectives were to: (i) assess quantity
of groundnut produced and stored; (ii) evaluate constraints during production and storage, and
(iii) learn more about marketing and sale of groundnuts.
2.4 Method and processing of Rice
Rice milling in modern age is the combination of several commercial milling operations that
produce better quality white rice from rough rice (Rice Paddy).
Rice milling process is all about producing edible milled rice after separating the husk (20%),
the bran layers (11%) & clean rice (69%) aka starchy endosperm.
In an ideal milling process this will result in 20% husk, 8−12% bran depending on the milling
degree and 68−72% milled rice or white rice depending on the variety. (Modern Rice Milling
Process _ Steps & Flowchart _ Hindustan Group).

26 | P a g e
2.5 Beans Processing method
The hulling is done mechanically in a dry mill (opposed to a wet mill/ depulper in washed
process. After hulling the beans are graded and sorted with machines that examine the size and
color of the beans. The beans are also sorted by large sieves with varying hole sizes by hand.
Processing white or yellow dry beans (Phaseolus vulgaris L.) into a heat treated flour
enhances the iron bioavailability of bean-based pastas (Processing white or yellow dry beans
(Phaseolus vulgaris L.) into a heat treated flour enhances the iron bioavailability of bean-
based pastas – ScienceDirect)
Source: (https://Store.extension.iastate.edu
2.6 Wheat Processing Methods
Wheat is processed into various grades of flour by cleaning, tempering, grinding, sifting, and
purifying. Flour is sold to the baking industry. Classes of wheat: The seven official classes of
whaet are soft white soft red spring, soft red winter, hard red winter, hard white, hard red spring
and durum. (https://Store.extension.iastate.edu)
2.7 Groundnut Processing Method
Four methods of processing (oil fried, sand fried, oven fried, smoked with seeds in shell) and
a control (raw unprocessed seeds) was adopted and laid out in a completely randomized design
(CRD) (https://www/researchgate.net)

27 | P a g e
2.8 Moisture, pH content, Ash Content and temperature of Cereals
Moisture Content
The high moisture contents could account for the variations in the frequency and percentage
occurrence in the stored food products (Groundnut – 31%), (Maize – 28%), (Beans – 20%),
(Rice – 11%) and (wheat - 10%) (Pg. 23, Ohabughiro et al., South Asian ResJ App Med. Sci;
Vol-2, Iss-3 (May-June, 2020).
Ash Content of Rice
In a study, composition of white rice flour showed ash content and 0.39% respectively.
Ash Content of wheat
the ash content of wheat varies from about 1.50 to about 2.00%. the pure endosperm contains
about 0.35% ash. Considering that the wheat kernel contains about 80% endosperm, it becomes
clear that the non-endosperm parts of the kernel (pericarp, aleurone, and germ) are very high
in ash when compared to endosperm.
Ash Content in Beans
The range of white beans is 3.8% for ash content.
Ash Content in Groundnut
The ash content is 3.08%
pH Content for Groundnut
The pH content for groundnut is a fatty acid having a range of 4 – 5.5
pH Content for Rice
It is slightly acidic in nature, normally pH measurement of rice is 6 – 6.7 in white rice.
pH Content for Beans
pH value of beans 5.60 – 6.50
pH Content for Wheat
pH range for wheat is about 5.5 and is acidic
Temperature of storage Facility of wheat
A laboratory experiment was designed and implemented for the storage temperature of wheat
about 27.50
C and 37.50
C.
Humidity for wheat
The humidity of wheat is 70%. From2:40pm (about ten days of storage period) 37.00
C.

28 | P a g e
CHAPTER THREE
3.0 MATERIALS
3.1 Media
3.1.1 Reagents
3.1.2 Other Material
Samples Collection:
Twenty frequently purchased brands of commercially sold Rice, beans, groundnut and wheat
flour were sourced from different stores in Agbani markets and transported to the laboratory
for analysis. Rice, beans, wheat and groundnut were used as the control experiment.
Isolation of Fungi in the Beans Flour Samples
Enumeration of fungal load in the samples was done using the pour plate method. Serial
dilution was carried out by adding 1g of bean flour into 10ml of sterilized water in a test tube,
which served as the stock solution. Afterwards, 1ml was pipetted from the stock solution and
added to 9ml of peptone water in another tube on the rack, which made it up to 10ml and the
same procedure was repeated for nine more tubes on the rack. Then 1ml of fifth dilutions was
dispensed in a petri dish and overlaid with molten potato dextrose agar (PDA). Then incubated
at 280
C for seven days. Distinct colonies observed were isolated and sub-cultured to obtain
pure cultures that were stored on potato dextrose Agar slants for characterization and
identification.
Identification and Characterization of Fungal Isolates
Isolates were identified macroscopically using morphological and cultural characteristics as
highlighted, using colour, elevation, shape on plates, texture, size and pigmentation.
Microscopic identification was also done by mounting the vegetative part of the fungus on a
microscopic slide with a drop of lactophenol cotton blue stain. Then covered with a cover slip
and examined under a microscopic objective lens, using x10 and x40
General Procedure for all Glassware
Stirbars, spatulas, funnels, flasks, beakers, and other reusable equipment
1. To remove organic residues, rinse glasware briefly with an organic solvent (acetone or
ethanol). The used rinse will then be discarded into the organic waste.
2. Use warm tap water and a brush with soapy water to scrub the inside of curved
glassware. This waste water can go down the sink.

29 | P a g e
3. Remove soapsuds with deionized water to avoid harsh water stains. The DI water rinse
should form a smooth sheet when poured through clean glassware. If this sheeting
action is not seen, more aggressive cleaning is needed. To expedite the glass-drying
process, rinse again with acetone to remove water. The residual acetone will go into the
organic waste container.
Cleaning Burets
1. Wash with soapy water
2. Rinse thoroughly with tap water
3. Then rinse three to four times with deionized water. The rinse should form a smooth
sheet when poured through clean glassware. If this sheeting action is not seen, more
aggressive cleaning is needed.
4. Burets need to be thoroughly cleaned to be used for quantitative work such as titrations.
To expedite the glass drying process, rinse again with a small volume of acetone to
remove water. The used acetone will then go into organic waste.
Cleaning Pipets and Volumetric Flasks
1. Clean pipets and volumetric flasks using warm soapy water
2. Rinse with tap water followed by three to four rinses with deionized water. This water
rinse should form a smooth sheet when poured through clean glassware. If this sheeting
action is not seen, more aggressive cleaning may be needed.
3. Dry using acetone to remove water. This acetone rinse will be disposed of in the organic
waste container.
Additional tips:
1. If water will affect the final solution, you can rinse with the solution you're using to
remove the water. Then, triple rinse with the solution you're using to remove the alcohol
or acetone.
2. Remove stoppers and stopcocks when they are not in use. Otherwise, they may "freeze"
in place.
3. You can de-grease ground glass joints by wiping them with a kimwipe soaked with
hexane or acetone. Do this in the hood vent to prevent you from breathing in the
chemicals.
4. Do NOT dry glassware with a paper towel or forced air. This can introduce fibers or
impurities. Normally, you can allow glassware to air dry on the shelf. Otherwise, if you
need to turn in glassware to the stockroom you can use a solvent as described above.

30 | P a g e
Preparation of Potato Dextrose Agar (PDA)
1. Suspend 39 grams in 1000ml distilled water. Heat to boiling to dissolve the medium
completely
2. Sterilize by autoclaving at 15lbs pressure (1210
c) for 15 minutes. Mix well before
dispensing
3. In specific work, when pH 3.5 is required, the medium should be acidified with sterile
10% tartaric acid.
4. The amount of acid required for 100 ml. of sterile, cooled medium is approximately
1ml.
5. Do not heat the medium after addition of the acid.
Screening for Aflatoxin Production of Fungal Isolate
The Isolates were cultured on Methyl Red Desiccated Coconut Agar (MRDCA) as formulated
by Atanda et al, (2011) and incubated at room temperature in a dark cupboard for three days.
The growth on the plate was exposed to 365nm Ultraviolet light to observe fluorescence
produced by the isolates.
Preparing an agar slant
We prepare slants by preparing agar in a beaker, distributing it into tubes, sterilizing the capped
tubes, and laying them at an angle to make a slanted surface as they cool.
1. Determine the volume of agar needed. We have found that 7 ml per 16 x 125 mm tube
gives us a slanted surface with good surface area and a “butt” about 1 inch deep.
Multiply the number of tubes needed by 7 ml and add 10% for waste.
NOTE: You may be able to tilt a rack so that tubes need not be laid out individually.
2. Place the desired number of tubes in a rack and obtain an equal number of screw caps.
3. Weigh out and mix the desired volume of agar in a beaker. The beaker should be close
to double the volume of agar to prevent spilling.
4. Add a stir bar, place the beaker in a microwave, and heat until the agar begins to foam.
Watch carefully so that the agar does not boil over.
5. Wearing gauntlet gloves for protection, carefully remove the beaker to a stir plate and
stir to make a uniform mix. If the agar is not completely dissolved, heat some more.
CAUTION: Hot agar that appears inactive may be superheated and may boil over violently if
disturbed. Handle with care, keeping the face away from the agar and bare skin protected.

31 | P a g e
6. While stirring to keep the agar mixed, use a large syringe (w/o needle) to distribute the
required volume into each tube.
7. Place a cap on each tube but do not screw them down. That way the tubes are able to
vent.
8. Sterilize on a liquid cycle (cycle 2 for our autoclave), remove the rack safely, then tilt
the tubes to allow the agar to cure.

32 | P a g e
CHAPTER FOUR
RESULTS
Table 4.1 Macroscopic and Microscopic Features of Isolated Fungal Isolates from Rice,
Beans, Groundnut and Wheat Samples.
S/N Isolate
Code
Macroscopic features Microscopic Features Microorga
nisms
Toxins-
producing Fungi
1 RA 10-3
Fusarium sp.: Pale, dark to
peach-violet
4.3± 0.7
Aspergillus niger: he
condidiophores of Aspergillus
sp. isolates were colourless,
thick walled, roughed, and
bearing vesicles. The diameter
of the conidiophores ranged
from 800 to 1200𝜇m
Fusarium sp.: Straight and
relatively slender tapered
and curved pointed
Aspergillus niger:
Identification were conidial
heads, stipes, colour and
length vescicles shape and
seriation, metula covering,
conidia size, shape and
roughness also colony
features including diameter
after 7 days, colour of
conidia, mycelia, exudates
and reverse, colony texture
and shape.
Fusarium
sp. &
Aspergillus
niger
Fusarium sp. &
Aspergillus niger
2 RB 10-3
Penicillium sp.: Surface:
Texture velvety to powdery;
Green, blue-green, gray-green,
white, yellow, or pinkish on
the surface. Reverse: usually
white to yellowish, sometime
red or brown
Fusarium sp: Pale, dark to
peach-violet
4.3± 0.7
Penicillium sp.: Hyphae
septate, hyaline.
Condidiophores simple and
branched. Phialides grouped
in brush-like clusters
(penicilli) at the ends of the
conidiophores; conidia
unicellular, round to ovoid,
hyaline or pigmented, rough
walled or smooth in chains
Penicillium
&
Fusarium
sp.
Penicillium &
Fusarium sp.

33 | P a g e
and curved pointed
3 RC 10-5
peach-violet
4.3± 0.7
Aspergillus sp.: The
condidiophores of Aspergillus
sp. isolates were colourless,
thick walled, roughed, and
bearing vesicles. The diameter
of the conidiophores ranged
from 800 to 1200𝜇m
Fumonisin sp.: Pale, dark to
peach-violet
4.3± 0.7
and curved pointed
Aspergillus sp.:
and shape.
Fumonisin sp.: Straight and
and curved pointed
Aspergillus
, Fusarium
and
fumonisin
Aspergillus,
Fusarium and
fumonisin
4 RD 10-3
Pale, dark to peach-violet
4.3± 0.7
Straight and relatively
slender tapered and curved
pointed
Fumonisin Fumonisin
5 RE 10-5
peach-violet
4.3± 0.7
Aspergillus parasiticus: The
condidiophores of A.
parasiticus isolates were
colourless, thick walled,
roughed, and bearing vesicles.
and curved pointed
Aspergillus parasiticus:
Fusarium
&
Aspergillus
Parasiticus
Fusarium &
Aspergillus
Parasiticus

34 | P a g e
The diameter of the
conidiophores ranged from
800 to 1200𝜇m
and shape.
6 BA 10-3
Penicillium citrinum exhibits
moderately slow growth on
SAB (Sabouraud-Dextrose
agar) at 300
c. surface texture is
velutinous (soft, velvety
surface) to floccose (woolly
tufts of soft “hairs”)
Pencicillium citrinum
produces septate, hyaline
(clear, not pigmented)
hyphae. Smooth-walled
conidiophores stipes are
rather long (100 – 300𝑚)
and is biverticillate (see
diagram at end of post).
Metulae are 12 – 15 in length
which are found in whorls 3
– 5 divergent structures
Penicllum
citrinum
Penicllum
citrinum
7 BB 10-3
the surface. Reverse: Usually
white to yellowish, sometimes
red or brown
P. chrysogenum shows
typically filamentous
hyphae with conidia, which
are asexual spores of the
fungi. The hyphae are
colourless, slender, tubular,
branched, and septate
hyphae. The hyphae are
formed from several threads
of mycelium which can get
intertwined into hyphal
network
Penicillum
chrysogenu
m
Penicillum
chrysogenum
8 BC 10-3
Penicillum
citrinum
Penicillum
citrinum

35 | P a g e
agar) at 300
rather long (100 – 300𝜇𝑚)
9 BD 10-3
agar) at 300
rather long (100 – 300𝜇𝑚)
Penicillum
citrinum
Penicillum
citrinum
10 BE 10-5
the surface. Reverse: Usually
white to yellowish, sometimes
red or brown
P. chrysogenum shows
typically filamentous
hyphae with conidia, which
are asexual spores of the
fungi. The hyphae are
colourless, slender, tubular,
branched, and septate
hyphae. The hyphae are
formed from several threads
of mycelium which can get
intertwined into hyphal
network
Penicillum
chysogenu
m
Penicillum
chysogenum
11. WA 10-
5
Pencillium sp.: Surface:
Penicillium sp.: Hyphae
septate, hyaline.
Penicillum,
Aspergillus
Penicillum,
Aspergillus,

36 | P a g e
red or brown
Aspergillus sp.: The
condidiophores of A. flavus
isolates were colourless, thick
walled, roughed, and bearing
vesicles. The diameter of the
800 to 1200𝜇m
peach-violet
4.3± 0.7
Aflatoxin: The fungi can be
recognized by a gray-green or
yellow-green mold growing on
corn kernels in the field or in
storage due to drought, heat or
insect damages during fungus
growth usually increases
aflatoxin levels
Condidiophores simple or
walled or smooth in chains.
Aspergillus sp.:
and shape.
and curved pointed
Aflatoxin: aflatoxins are
usually detected and
identified accoirding to their
absorption and emission
spectra, with peak
absorbance occurring at
360nm. B toxins exhibit blue
fluorescence at 425nm.
, fusarium,
Aflatoxin
fusarium,
Aflatoxin

37 | P a g e
12. WB 10-
5
4.3± 0.7
Straight and relatively
slender tapered and curved
pointed
Fusarium Fusarium
13. WC 10-
3
The colony is flat, downy to
woolly and is covered by
grayish, short, aerial hyphae in
time. The surface is greyish
whte at the beginning which
later darkens and becomes
greenish black or olive brown
with a light border
Alternaria spp. Have septate,
brown hyphae.
Condiophores are also
septate and brown in colour,
occasionally producing a
zigzag appearance. They
bear simple or branched
large conidia (7-10×23-34
𝜇𝑚)
Alternaria
alternate
Alternaria
alternate
14. WD 10-
3
Surface: Texture velvety to
powdery; Green, blue-green,
gray-green, white, yellow, or
pinkish on the surface.
Reverse: usually white to
yellowish, sometime red or
brown
Alternaria alternate: The
colony is flat, downy to woolly
and is covered by grayish,
short, aerial hyphae in time.
The surface is greyish whte at
the beginning which later
darkens and becomes greenish
black or olive brown with a
light border
Ochratoxin is a mycotoxin
produced by several species
of Aspergillus and
penicillium fungi that
structurally consists of para-
chlorophenolic group
containing a
dihydroisocoumarin moiety
that is amide-linked to L-
phenylalaine.
Alternaria alternate:
brown hyphae.
𝜇𝑚)
Ochratoxin
, alternaria
alternate
Ochratoxin,
alternaria
alternate

38 | P a g e
15. WE 10-
3
Surface: Texture velvety to
powdery; Green, blue-green,
gray-green, white, yellow, or
pinkish on the surface.
Reverse: usually white to
yellowish, sometime red or
brown
The surface is greyish white at
light border.
Ochratoxin: Ochratoxin is a
mycotoxin produced by
several species of
Aspergillus and penicillium
fungi that structurally
consists of para-
chlorophenolic group
containing a
dihydroisocoumarin moiety
that is amide-linked to L-
phenylalaine.
brown hyphae.
𝜇𝑚).
Ocharatoxi
n, alternaria
alternate
Ocharatoxin,
alternaria
alternate
16. GA 10-3
aflatoxin levels
Fumonisin:
spectra, with peak
Fumonisin:
brown hyphae.
Aflatoxin,
fumonism
and
alternaria
alternate
Aflatoxin,
fumonism and
alternaria
alternate

39 | P a g e
The surface is greyish whte at
light border
𝜇𝑚)
17. GB 10-3
Aspergillus flavus: The
condidiophores of A. flavus
isolates were colourless, thick
walled, roughed, and bearing
vesicles. The diameter of the
800 to 1200𝜇m
Aflatoxins: The fungi can be
aflatoxin levels.
Aspergillus flavus:
and shape.
Aflatoxins:
Aspergillus
flavus,
Aflatoxins
Aspergillus
flavus, Aflatoxins
18. GC 10-3
with a light border
brown hyphae.
𝜇𝑚)
Alternaria
alternate
Alternaria
alternate

40 | P a g e
19. GD 10-3
4.3± 0.7
Aflatoxin:The fungi can be
aflatoxin levels
Fusarium: Straight and
and curved pointed
spectra, with peak
Fusarium
&
Aflatoxin
Fusarium &
Aflatoxin
20. GE 10-3
aflatoxin levels
with a light border
Penicillum rubens: Surface:
spectra, with peak
brown hyphae.
𝜇𝑚)
Penicillum rubens: Hyphae
septate, hyaline.
Condidiophores simple or
Aflatoxins,
alternaria
alternate,
penicillum
rubens
Aflatoxins,
alternaria
alternate,
penicillum rubens

41 | P a g e
red or brown
walled or smooth in chains.

42 | P a g e
Showing the Macroscopic and Microscopic Features of Fungal Isolates in rice, beans,
wheat, groundnut flour samples
Figure 1: Macroscopic features
Figure 2: Microscopic features

43 | P a g e
Table 4.2 Summary of Mycotoxins type, products affected and their effects after
consumption
S/N Mycotoxin & Toxin
Producing Fungi
Commodities Health hazards Toxlaties
1. Fusarium sp. and Aspergillus
niger
Rice, groundnut Keratitis, onychomycosis
2. Penicillium sp. and Fusarium
sp.
Rice, beans Asthma, Pneumonia
3. Fumonisin alternaria, alternate Rice, groundnut Oesophageal cancers
4. Ochariaroxin Wheat Balkan endemic nephropathy
(BEN) and chronic interstitial
nephropathy (CIN), as well as
other renal diseases
5. Aspergillus sp. Parasiticus Rice Liver cancer, growth altering, bile
duct proliferation
6. Aspergillus flavus Groundnut Liver camcer
7. Penillicum sp. Beans Superficial infection (Keratitis
and otomycosis), allergic
pulmonary disease

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CHAPTER FIVE
CONCLUSION AND RECOMMENDATION
CONCLUSION
All these microorganisms have contributed greatly to the health of human and livestock as well
as the economy. Rice, beans, wheat, groundnut are highly consumed in Nigeria and it is very
important to know the levels of fungi assessing in the production suitable cereals in order to
provide suitable measures to reduce its occurrence in food samples. Aspergillus sp. penillicum
sp., fumonisina sp., fusarium sp, Aspergillus niger, Aflatoxin, Alternaria alternate, Ochratoxin
mucus were isolated from the food samples. The study therefore concludes that cereals grain
(rice, groundnut, wheat, beans) commercially solid in Enugu are contaminated with toxins
producing organisms (fungi). Some species of the fungi are known to produce toxins.
Damaged grains should be stored and eliminated to avoid contamination with Micro-toxigenic
organisms.
Also stringent law on raw legume grains should be incorporated and enforced in order to reduce
the spread of toxins in food samples. Mycotoxins have implications between nations.
Prevention of fungal invasion of commodities is fat the most effective method of avoiding
mycotoxins problems. Mycotoxins consideration should be an integral commodity
management program focusing on the maintenance of commodity quality from the field to the
consumer.
Several effective ways for prevention and control of hazardous fungi and their dangerous
mycotoxins have been presented. The methods include biological control, physical and
chemical treatment.
RECOMMENDATION
There is little doubt that high levels of exposure of people to food-borne mycotoxins is a serious
threat to public health.it is developmental issue, which embraces childhood survival,
demographics, immune system function, the economic and human resource drain due to
cancers, as well as food security where livestock feeds are contaminated.
Research is needed on inexpensive and appropriate sampling and testing protocols. Research
on identification and application of appropriate technologies for obtaining low grain moisture
at harvest and maintain low grain moisture during storage are needed.

45 | P a g e
Research is needed on traditional food preparation technologies such as fermentations and
nixitimalization, or chelating additives such as clays or yeasts that may lower mycotoxins in
prepared foods.

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REFERENCES
Abdullahi, A. & Haile, A. (2012). Research on the control of insect and rodent pests of wheat
in Ethiopia. In wheat research in Ethiopia: a historical perspective. Addis Ababa,
IAR/CIMMYT.
Atanda, S. A, Pessu P.O., Agoda S. Isong I. U., Adekalu O.A.,Echendu M.A. and Falade T.C.
(2011) African Journal of Microbiology Research, Vol. 25, pp. 4373-4382.
Atanda, O., Ogunrinu, M. and Olorufemi, F. (2011). A neutral red desiccated coconut agar for
rapid detection of aflatoxigenic fungi and visual determination of aflatoxins. World
mycotoxin J. 4:147-155.
Badmos A.O., Olonode, S., Oni E.O. and Adeleye, T.M (2021). Isolation of Mycotoxigenic
fungi and quantificaiton of Aflatoxins from Bean flour sold in Abeokuta Nigeria, Nig. J.
Biotech. Vol, 38 (1): 68-73
Buckland, P.C. (2021). The early dispersal of insect pests of stored products as indicated by
archaeological records. J. Stored Prod. Res., 17(1): 1-12
Ohabughiro et al., South Asian Res. J App Med. Sci.; Vol-2, Pg. 23, Iss-3, 2020
Food and Agricultural organization of United Nations, (FAOSTAT, 2016)
Hampson D., Schuelke J., & Quirein J. (2014). Use of multi-attribute transforms to predict log
properties from seismic data. Geophysics, 66(1), 220-236
Hammons R.O, (2014). Early history and origin of the groundnut: Culture and uses (pp. 17-
45).
McFarlane J.A, (2019). Guidelines for pest management research to reduce stored food losses
caused by insects and mites. Overseas Development and Natural Resources Institute
Bulletin No. 22. Chatham, Kent, UK.
NRC (National Research Council), (2016). Lost crops of Africa, vol. 1. Washington, DC,
National Academy Press.
Naidu R.A., Botternberg H., Subrahmanyam P. Kimmins F.M., Robinson D.J., & Thresh J.M
(2016).
Ntare B.R., Waliyar F., Ramouch M., Masters E., & Ndjeunga J (2016). Market prospects for
groundnut in West Africa (p. 252, CFC Technical Paper No.39).
Ndjenuga J., Ntare B.R., Waliyar F. Echekwu C.A., Kodio O., Kapran I., & Da Sylvia A (2008).
Early Adoptiion of modern groundnut varieties in West Africa Working paper series No.
24).
Panagiotakopulu, E. & Buckland, P.C. (2021). Insect pests of stored products from late Bronze
age Santonrini, Greece. J. Stored Prod. Res., 27(3): 179-184.

47 | P a g e
Rashkov P., (2013) Senegal: Unvrai echappement du development agricole ralenti? (p. 10)
Reddy T.Y., Reddy V.R., & Anbumozhi V., (2013). Physiological responses of groundnut
(Arachis hypogea L.) to drought stress and its amelioration: A critical review. Plant
growth Regulation, 41, 75-88.
Tyler, P.S. & Boxall, R.A. (2014). Post-Harvest loss reduction programmes: a decade of
activities: what consequences? Trop. Stored Prod. Info, 23:13-28.
Waliyar F. Kumar P. L., Ntare B.R., Monyo E., Nigam S. N., Reddy A.S., Osiru M., & Diallo
A.T (2017). A Century of Research on Groundnut Rosette Disease and its management
(Information Bulletin), 75.
Oaya C.S., Malgwi A.M., & Samalia A.E. (2012). Damage Potential and Loss Caused by the
Groundnut Bruchid Caryedon Serratus Olivier (Coleoptera: Bruchidae) on Stored
Groundnut and Tamarind in Yola. IOSR Journal of Agriculture and Veterinary Sceince,
1(6), 58 – 62.
Coulibaly M.A., Ntare B.R., Gracen V.E., Danquah E., & Ofori K (2017). Groundnut
production constraints and Farmer’s preferred varieties in Niger. International Journal
of Innovative science, Engineering & Technology, 4, 202-207.
https://en.m.wikipedia.org/wiki/list_of_rice_diseases
https://www.britannica.com
https://plantvillage.psu.edu/topics/beans/infos
https://harvestobale.com>Beans _harvest and storage, 2022
(https://Store.extension.iastate.edu)
Completely randomized design(CRD) (https://www/researchgate.net)

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