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Chapter

Growth of Fungal Cells and the

Production of Mycotoxins
Márcia Regina Ferreira Geraldo Perdoncini,
Maria Josiane Sereia, Fabio Henrique Poliseli Scopel,
Maysa Formigoni, Eliane Sloboda Rigobello,
Stéfani Caroline Beneti, Flavia Aparecida Reitz Cardoso,
Livia Benossi Marchi, Claudio Gomes da Silva Junior,
Paula Gimenez Milani Fernandes,
Tuan Henrique Smielevski de Souza, Priscila Wielewski,
Erica Gomes de Lima, Angelivia Gregório,
Maria Rosa Trentin Zorzenon, Juliana Cristina Castro,
Vanessa de Cássia Mendes Del Bel,
Magali Soares dos Santos Pozza
and Leila Larisa Medeiros Marques

Abstract

Some filamentous fungi are able to grow in food and produce toxic metabolites.
It occurs mainly in grains, cereals, oilseeds and some by-products. The growth of
fungi in a particular food is governed largely by a series of physical and chemical
parameters. The production of toxic metabolites is not confined to a single group
of molds irrespective of whether they are grouped according to structure, ecology,
or phylogenetic relationships. Mycotoxins can be carcinogenic and cause several
harmful effects to both human and animal organisms, in addition to generating
large economic losses. The major mycotoxins found in food are the aflatoxins,
fumonisins, ochratoxins, patulin, zearalenone, and trichothecenes, generally stable
at high temperatures and long storage periods. Considering the difficult prevention
and control, international organizations for food safety establish safe levels of these
toxins in food destined for both human and animal consumption. Good agricultural
practices and control of temperature and moisture during storage are factors which
contribute significantly to inhibit the production of mycotoxins. The use of some
fungistatic products, such as essential oils and antioxidants, as well as physical,
mechanical, chemical, or thermal processing, represents important methods to have
the concentration of mycotoxins reduced in food.

Keywords: aflatoxins, ochratoxins, patulin, fumonisins, zearalenone

1
Cell Growth

1. Introduction

Microorganisms constitute the main cause of deterioration and losses in food.

Fungi can be mono- or multiple-cell organisms, mostly aerobic, which survive
within a wide range of moisture, temperature, and pH. They inhabit nature freely
and feed on the absorption of organic matter.
Their presence in food can be derived from the field, such as parasites, plant
pathogen, and even coming from the soil or equipment used in the management of
culture crops. In addition, they appear as storage microbiota and develop during the
entire storage process, which may lead to great physical-chemical and sensory losses
in food products, in addition to the production of mycotoxins.
Mycotoxins are substances secreted by the secondary metabolism of filamentous
fungi, which are produced by certain fungus lineages and in particularly favorable
conditions. A few hundreds different mycotoxins are known, some characterized
by their antibiotic potential and others extremely toxic to men and animals. This
chapter will present the fungi growth conditions to produce mycotoxins, the major
mycotoxins occurring in food, levels of toxicity, favorable conditions to excretion,
and control measures regarding their production.

2. Fungi

Fungi are able to grow in practically all ecological niches; however, they can
be found prevailing particularly in dead organic matters present in the soil. They
include eukaryotic organisms commonly known as yeasts, which normally grow in
the form of single cells, and molds, which grow by forming ramified chains called
hyphae. Even though most fungi are harmless to human beings, the exposition to
specific lineages and their metabolites may result in some clinical manifestations in
men and other animals.

a. Infections or diseases derived from the invasion of living tissue. The growth
of a fungus on the top of or inside a body is named mycosis. Mycoses can have
varied severity, encompassing from relatively benign and superficial infections
to severe diseases that threaten life.

b. Hypersensitivity reactions. Some fungi promote an immune response which

can result in allergic reactions after exposition to a specific fungus antigen.
Exposition to fungi, either by developing in a host or in the environment, may
cause the development of allergic symptoms in the case of a re-exposition. For
example, Aspergillus spp., a common saprophyte, often found in nature as a
filamentous fungus from leaves, corresponds to a potent, common allergen,
which often triggers asthma and other hypersensitivity reactions.

c. Mycotoxicosis. It is an intoxication resulting from ingestion of food or feed

containing toxic metabolites, that is, mycotoxins [1].

The major toxigenic strains of interest for the public health belong to the genera
Aspergillus spp., Penicillium spp., and Fusarium spp. It is important to highlight that
not all fungi produce mycotoxins as well as that a single fungus species can produce
many secondary toxic compounds. The presence of a mycotoxin in food is necessar-
ily conditioned to fungus development, but it does not mean that a product without
any fungi could not contain mycotoxins [2]. A cereal stored under poor conditions
of temperature and moisture provides a favorable medium for fungus development

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and the production of mycotoxins. Once a mycotoxin is produced, even upon the
destruction of the fungus biomass, through a drying process, for example, the
metabolites excreted remain in the product.
As heterotrophs, fungi require organic compounds for both synthesis of biomass
(anabolic metabolism) and production of energy to drive these reactions (catabolic
metabolism). These aspects are referred to as primary metabolism. The secondary
metabolisms are distinct from primary metabolism in so far as they occur optimally
after a phase of a balanced growth and are often, but not always, associated with
morphogenetic changes such as sporulation; the production of particular secondary
metabolites is usually restricted to a small number of species and may be species,
or even strain, specific; it has not generally been possible to rationalize the bio-
logical function of secondary metabolites, although some are very active against
microorganisms (antibiotics), plants (phytotoxins), or animals (mycotoxins).
Although secondary metabolites in general, and mycotoxins specifically, do not
form a neat and a recognizable group of organic structures, they can be classified in
terms of the biosynthetic pathways leading to their production. This is so because
the processes of primary and secondary metabolism are linked by a relatively small
number of simple intermediates such as acetyl coenzyme A, mevalonic acid, and
amino acids [3–5].

3. Fungal growth in food

The growth of fungi in a particular food is governed largely by a series of physi-

cal and chemical parameters, and definition of these can assist greatly in assessing
the food’s stability. The factors which govern spoilage are physical and chemical, and
there are eight principal factors: water activity; hydrogen ion concentration; temper-
ature, of both processing and storage; gas tension, specifically of oxygen and carbon
dioxide; consistency; nutrient status; specific solute effects; and preservatives [6].
In general, fungal deterioration stands out under conditions in which bacterial
deterioration is controlled, either by low water activity (aw), pH, temperature, and/
or the presence of inhibitory agents. Raw material quality and contamination of the
production environment will directly interfere with the initial contamination of the
products. The processing and storage parameters will influence on time to the appear-
ance of visible fungal colonies and, therefore, the shelf life of a food product [6, 7].
The deterioration of food by filamentous fungi starts with contamination of the
product by fungal spores originating from the environment. When intrinsic param-
eters, such as water activity (aw) and pH, as well as temperature, are favorable, the
spores will germinate and form a visible mycelium, deteriorating the product [8, 9].
Temperature and aw are recognized as the most important parameters for deter-
mining fungi cell growth, but pH also influences that development. The external
pH value influences not only fungal growth rate but also metabolism. Aspergillus
flavus isolates produce more aflatoxins when the external pH becomes increasingly
acidic. In the case of the cereal pathogen Fusarium graminearum, trichothecene
production is induced only under acidic pH conditions [10].
The moisture content of grains and other dried foods is such that there is seldom
any problem with the growth of bacteria and yeasts, but there are frequent prob-
lems with the growth of molds (fungi). Unless the aw is reduced to below approxi-
mately 0.7, molds will grow on any food, and as the relative humidity in the humid
tropics is generally more than 70%, almost all dry foods will become moldy when
stored in the humid tropics unless the moisture content is reduced to an aw of less
than 0.70, followed by storage that will protect that food from absorbing moisture
from the high-humidity environment [11–14].

3
Cell Growth

4. Mycotoxins

Mycotoxins have been known for a very long time, but they only became more
intensively studied after an incident occurred in 1960 in England, involving the
death of 100,000 birds fed on feed contaminated with fungus Aspergillus flavus.
Mycotoxins are produced mainly by mycelial structures present in filamentous
fungi. Even though their function for produced lineages is yet to be clarified,
mycotoxins are secondary metabolites that apparently do not present a biochemical
meaning to fungus growth and development [7, 15].
According to the Food and Agriculture Organization (FAO), it is estimated that
the contamination of food products by fungi and their toxic metabolites generates
qualitative and quantitative losses for around 25% of the agricultural food produc-
tion worldwide, occurring majorly in regions of tropical and subtropical climate,
where higher temperature and moisture favor microbial proliferation [16, 17].
Primary metabolites of fungi, such as of other organisms, are essential to
growth, while secondary ones are formed during the final exponential growth phase
and have not a clear significance to the growth or metabolism of the organism [1–3].
In general, these metabolites appear to be formed whenever large amounts of
primary metabolites precursors, such as amino acids, acetate, and pyruvate, among
others, are accumulated. The synthesis of mycotoxins represents a way for fungi to
reduce the amount of precursors, which are not required to metabolism [1–3].
They are constituted by a large variety of chemical assembles, which provides
them with several biological activities, classified according to the toxicity level
exerted on human and animal organisms [2] possibly with carcinogenic, mutagenic,
teratogenic, cytotoxic, neurotoxic, nephrotoxic, immunosuppressant, and estro-
gen effects. However, its toxicity largely depends on the amount ingested, time of
exposition, and possible synergy with the ingestion of many different mycotoxins
simultaneously, in addition to individual physiological conditions [4].
Mycotoxin ingestion can produce both acute and chronic toxicities. Acute is
characterized by a rapid onset and an obvious toxic response including rapid death.
Chronic is resulting from low-dose exposure to mycotoxins over a long period of time,
with toxic responses including cancers such as hepatocellular carcinoma [18, 19].
The International Agency for Research on Cancer (IARC) in Lyon (France)—
through its IARC Monographs program—has performed the carcinogenic hazard
assessment of some mycotoxins in humans, on the basis of epidemiological data,
studies of cancer in experimental animals, and mechanistic studies. There are five
groups classified according to the scientific evidence for their carcinogenicity:
Group 1, carcinogenic to humans; Group 2A, probably carcinogenic to humans;
Group 2B, possibly carcinogenic to humans; Group 3, not classifiable as to its
carcinogenicity to humans; and Group 4, probably not carcinogenic to humans.
Carcinogenic effects and related mechanisms of some mycotoxins (e.g., aflatoxins)
are well-known. However, for some other important mycotoxins (e.g., OTA, FUM
B1, and FUM B2), there is a need for continued research on understanding these
mechanisms [20–24].

4.1 Aflatoxins

Many types of aflatoxin (14 or more) occur in nature, but only four of them are
particularly dangerous to humans and animals. Aflatoxins are mainly produced by
species of Aspergillus flavus and Aspergillus parasiticus and classified in aflatoxins
B1 and B2 and G1 and G2. Their name derives from the fluorescence emitted after
absorption of ultraviolet light at 365 nm (B, blue; and G, green). They are char-
acteristically heat-resistant and bear the process of sterilization with a structure

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Growth of Fungal Cells and the Production of Mycotoxins
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remaining unaltered for long periods of storage. Their chemical structure allows
good solubility in organic solvents and are insoluble in water proving sensitive in
alkaline medium, which decreased their toxicity [22]. The group of aflatoxins is
considered by the IARC as belonging to Group 1—cancer-causing substances to
men [21].
Mycotoxin B1 is pointed out as the most toxic in the group and can generate
metabolites in the organism of mammals (M1). Aflatoxin M1, generated by B1
metabolism, is transported to milk at a proportion of 1% of the total ingested and
can also be found in animal tissues in which there is a high exposition to this toxin.
Subsequently, humans can ingest this aflatoxin through breast milk, milk, and
milk-derived products, especially in areas where grains and cereals of poor quality
are used to feed animals [17–23].
Birds are the most sensitive animals to aflatoxins, and whenever ingested in
contaminated feed, they present fast absorption through the gastrointestinal tract.
The effects include damages to the liver, harm to the productivity and reproductive
efficiency, decreased production of eggs, lower quality of egg shell, lower quality
of carcass, and increased susceptibility to diseases. Pigs are, somehow, less sensitive
than birds. Aflatoxin is also hepatotoxic to these animals, and its chronic effects are
largely attributed to damage to the liver. In cattle, the primary symptom is reduction
in weight gain. In addition, milk production is reduced [25–27].
Aflatoxins occur mainly in products such as peanut and nuts, maize, and cotton-
seed, among others, which is associated with pre-crop contamination. Cultures such
as coffee, rice, and spices can also be contaminated by these toxins post-crop [26].
Many countries introduced legislation specific to mycotoxins. Most of these
legislation rules are regarding aflatoxins, alkaloids of ergot, deoxynivalenol, and
ochratoxins. Even though legal measures are yet to be uniformed at a worldwide
level, the Codex Alimentarius Commission is gathering efforts to establish interna-
tional guidelines regarding levels of mycotoxins. For aflatoxins, the Food and Drug
Administration established the maximum limit of 20 ppb to maize, peanut, cotton
bran, and other food and ingredients for animals [27–31].

4.2 Ochratoxin A

The major toxins produced by Penicillium verrucosum, Aspergillus ochraceus, and

Aspergillus carbonarius are ochratoxin A, ochratoxin B, and ochratoxin C. Among
these toxins, ochratoxin A is considered the most toxic and, according to the IARC,
a possible cancer-causing substance to humans (category 2B). Recent researches
conducted over the past 6 years related to ochratoxin toxicity encompassed the
identification of factors involved in carcinogenesis and provided strong evidence
to a reclassification of the Group 2B into the Group 2A (probably carcinogenic to
human beings) [1, 4, 20].
Among the species of Penicillium, P. verrucosum is the major source of ochratoxin
A and the most common species in countries of temperate, cold climate, while A.
ochraceus, A. carbonarius, and other species from the Group A niger are the most
common in tropical, hot climates. Another species of Penicillium produced from
ochratoxin A is P. nordicum. P. verrucosum is especially associated with stored cere-
als, that is, post-crop fungi. This mycotoxin is often found in animal feed and food
as wheat, rye, coffee, nuts, and, at a lower degree, grapes, raisins, wine, or products
derived from pork. There have been reports of this mycotoxin detected in blood and
milk breast of individuals exposed to its ingestion [1–4]. The levels can accumulate
in the tissues of the body and fluids of human beings or animals who consume
contaminated food. Evidence shows that ochratoxin A is slowly eliminated from the
body [17, 25].

5
Cell Growth

The structure of these toxins is derived from L-phenylalanine, which makes it a

potent inhibitor of the enzyme phenylalanine-RNAt synthase, responsible for the
synthesis of proteins of high turnover rich in phenylalanine—a functional role for
kidney homeostasis. In addition, it interferes in the lipid peroxidation causing dam-
ages to the DNA and oxidative stress. Therefore, it is suspected that ochratoxin A is
one of the cancer-causing agents in the urinary tract as well as related to the dam-
ages to kidneys occurred in Eastern Europe. Researches indicate that practically all
Europeans have some ochratoxin concentration in their blood. Human exposition to
ochratoxin occurs primarily from brown bread. In some parts of Europe, the most
significant exposition derives from the consumption of animal products, especially
those formulated based on pig blood [32, 33].
Considering the toxic effects of ochratoxins, a tolerable weekly intake (TWI)
of 120 ng/kg of body weight (pv) was established by the European Food Safety
Authority (EFSA). The meeting of the Committee of Specialists on Agricultural
Contaminants in food (European Commission, DG Health, and food safety) has been
considering establishing limits to herbal teas, infusions, and baking [32]. Even though
ochratoxins B and C are hepatotoxic, immunotoxic, teratogenic, and genotoxic,
maximum tolerable limits are yet to be established regarding these toxins [34, 35].

4.3 Patulin

Patulin (polyketide lactone 4-hydroxy-4H-furo (3.2c) pyran-2 (6H)-one) is a

secondary metabolite produced by several species of Penicillium, Aspergillus, and
Byssochlamys in conditions of high activity of water (0.95–0.99) and temperature
of 0–31°C. Food which are more susceptible to contamination by patulin in human
diet are apples and by-products (puree and juices). Even though contamination
with patulin is mainly associated with areas of contaminated tissue, it can penetrate
around 1 cm in healthy regions of the fruit [1].
Patulin has been reported as mutagenic, neurotoxic, immunotoxic, and geno-
toxic and to cause gastrointestinal damages in rodents. There is also some concern
that similar effects may occur in humans through a long-term consumption of
food and beverage contaminated with this mycotoxin. The IARC classified patulin
as Category 3, non-classifiable regarding its carcinogenicity to human beings.
Because of its toxicity, the Joint Food and Agriculture Organization/World Health
Organization Expert Committee on Food Additives (JECFA) established a maxi-
mum tolerable limit for daily intake (PMTDI) for patulin of 0.4 μg/kg of body
weight [34]. The Codex Alimentarius established a maximum level for patulin of
50 μg/kg in apple juice, and the European Union (EU) adopted a maximum level
of 50 μg/kg 1 for juices, beverages, and fermented milk products containing apple
juice, 25 μg/kg in solid products containing apple, and 10 μg/kg in apple-based
products as well as baby food. Although some limits have been established, some
countries, such as Pakistan, do not have any specific legislation for this toxin [36].

4.4 Trichothecenes

Trichothecenes are a group of secondary metabolites produced by fungi

belonging to the genus Stachybotrys and mainly Fusarium, in which F. graminearum
and F. culmorum are the most important. Fusarium graminearum grows greatly at
a temperature of 25°C and activity of water above 0.88, while F. culmorum grows
well at 21°C and activity of water above 0.87 [1].
The group of trichothecenes is composed of over 200 mycotoxins and carries
this name because of their chemical structure constituted of a ring with tetracyclic
skeleton 12,13-epoxitrichothecenes. They also present varied ligand assembles, which

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DOI: http://dx.doi.org/10.5772/intechopen.86533

provides toxicity. These toxins are classified in type A, in which toxins T-2, HT-2,
15-monoacetoxyscirpenol (15-MAS), and diacetoxyscirpenol (DAS) are found, and
type B, in which deoxynivalenol (DON) occurs. Deoxynivalenol is an epoxy-
sesquiterpenoid which occurs naturally combined with 3-acetyl-deoxynivalenol
(3AcDON) and 15-acetyl-deoxynivalenol (15AcDON), which increases DON toxicity.
According to the IARC, DON is classified in level 3, that is, it does not represent a risk
of cancer induction, although co-occurrence with aflatoxin may increase aflatoxin
carcinogenicity. DON can also coexist combined with zearalenone [1, 2, 37].
Despite the existence of a relatively large amount of different trichothecenes,
their natural occurrence in food and feed is mainly related to nivalenol, deoxyniva-
lenol, toxin T-2, diacetoxyscirpenol, and less often furarenone-X, toxin HT-2, and
neosolaniol.
DON is probably the most largely distributed mycotoxin in food and feed often
detected in wheat, barley, rye, malt, oat, maize, and consequently products derived
from these cereals, such as flours and beers, and less often rice, sorghum, and
triticale. It is a heat-resistant toxin which is not altered during food processing, in
addition to being stable over long storage periods [37, 38].
Discovered in the early 1970s, DON is also popularly known as vomitoxin for its
acute effect on the ingestion of high doses causing symptoms similar to enterotoxins
of Staphylococcus aureus and Bacillus cereus, such as nausea, vomit, abdominal pains,
diarrhea, leukopenia, bleeding, and even death in humans and animals [37, 38].
Pig is the most sensitive animal to DON, and the chronic effects of ingestion of
contaminated feed result in reduced weight gain and growth, infertility, including
the birth of animals with malformation, and miscarriage. Birds are more tolerant
than pig, and the effects of intoxication are lower quality and weight of the eggs
produced. Cattle are more tolerant, possibly due to the toxin degradation in second-
ary metabolites in the rumen. The effects in cattle include lower feed consumption
and conception rate in addition to reduced milk production [2, 37].
The Codex Alimentarius Commission (CAC) establishes the maximum level of
2 μg/kg for DON for wheat, maize, and barley. The European Union, in turn, proposes
0.75 μg/kg for cereals and flour and 0.2 μg/kg for wheat germ [38].

4.5 Zearalenone

Also known as toxin F-2, it is an estrogen produced mainly by F. graminearum,

F. culmorum, and F. sporotrichioides. Toxigenic strains of Fusarium can develop in
soft climate and the optimum temperature to produce zearalenone is until 28°C. It
is commonly found in several cereals, such as wheat, barley, sorghum, and mainly
maize [6].
Zearalenone is a lactone of beta-resorcylic macrocyclic acid with a structure sim-
ilar to 7ß-estradiol, main hormone produced in female human ovary. Zearalenones
are considered micro-estrogenic due to their capacity to hamper the effect of steroid
hormones interfering in human and animal reproductive capacities. It also influ-
ences the production of testosterone, progesterone, and estradiol. Zearalenone is
able to imitate the activity of estrogen in the reproductive tract, including accessory
glands, such as the prostate [40–42].
It causes hyperestrogenism in pig, whose symptoms are swelling and redness of
the vulva and hyperdevelopment of the uterus and mammary glands. In addition to
present significant effects on the increase of endometrial secretions and synthesis
of uterine proteins and higher weight of reproductive organs [31].
Birds are more resistant to intoxication by zearalenone, but the many associa-
tions of fusariotoxin with other mycotoxins can result in severe losses. The produc-
tion of zearalenone may occur either in the field or post-crop in inadequate storage

7
Cell Growth

conditions (high moisture). The detection of this mycotoxin in bird feed has been
considered a biomarker for other toxins belonging to the genus Fusarium [31].
Despite some evidence, the IARC assessed the carcinogenicity of zearalenone
and found it to be a possible cancer-causing substance to humans. Zearalenone
residues do not seem to be an issue after consumed.

4.6 Fumonisins

They were discovered in 1988 and described as fumonisins B1, B2, and B3, in
which B1 occurs more frequently. However, fumonisins constitute a group encom-
passing over 16 substances already identified, called B1 (FB1, FB2, FB3, and FB4),
A1, A2, A3, AK1, C1, C3, C4, P1, P2, P3, PH1a, and PH1b. They are highly water-
soluble unlike other mycotoxins and do not have an aromatic structure or a single
chromophore to analytically facilitate its identification, therefore being difficult to
identify through ultraviolet spectrum [25].
These substances are produced by several species of the genus Fusarium,
especially by Fusarium verticillioides (previously classified as F. moniliforme), F.
proliferatum, and F. nygamai, in addition to Alternaria alternata. Other species, such
as F. anthophilum, F. dlamini, F. napiforme, F. subglutinans, F. polyphialidicum, and F.
oxysporum, also have been included in the group of these mycotoxin products [25, 38].
Fumonisins have been found as a common contaminant in maize-based food
and feed. When ingested, fumonisins present low bioavailability and are rapidly
metabolized and excreted. The carcinogenic nature of fumonisins does not seem to
involve an interaction with DNA. Their mode of action is related to their toxicity
in the interference of the biosynthesis of sphingolipid, which are very important to
maintain the integrity of the cell membrane, regulation of receptors of cell surface,
ion pump, regulation of growth factors, and other vital systems for the functioning
and survival of the cell. In addition, fumonisins are potent immunosuppressant
agents and can enhance the susceptibility to diseases [38–44].
These toxins cause many diseases in animals, such as leukoencephalomalacia
(LEME) in horses and pulmonary edema in pigs. LEME is a noninfectious, highly
fatal disease which affects the central nervous system of horses and other equines
with a large distribution worldwide and considered a disease derived from regions
of temperate, tropical climate. LEME involves metabolic alterations that produce
the softening of the white substance of the encephalon as well as its liquefaction,
which occurs due to a mycotoxin present in the feed. The disease occurs because of
the need to supplement horse diet with grains of maize or feed containing them in
their formulation due to the lack of fodder in pastures [43].
Even though their effects on human beings are difficult to determine, fumoni-
sins have been statistically associated with high occurrence of esophageal cancer
in South Africa and liver cancer in certain endemic areas in China. Based on toxi-
cological evidence, the IARC declared the toxins of F. moniliforme as potentially
carcinogenic to humans (Class 2B) [44].

4.7 Modified mycotoxins

The major mycotoxins in food (aflatoxins, ochratoxins, patulin, deoxynivalenol,

zearalenones, and fumonisins) occur freely and coexist with modified mycotoxins.
The term “mask mycotoxin” was used for the first time for mycotoxin M1, derived
from the hydroxylation of aflatoxin B1, excreted in the milk of animals which
consume contaminated feed with aflatoxin B1. In the mid 1980s, a new compound
derived from zearalenone was found to be involved in cases of smycotoxicosi and no
correlated to the mycotoxins found in the food matrix in question [45].

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DOI: http://dx.doi.org/10.5772/intechopen.86533

Recently, with the modernization of the means to detect the toxins, such as high-
performance liquid chromatography associated with mass spectrometry, many other
compounds derived from mycotoxins were discovered, and the term “mask myco-
toxin” made way to the name of modified mycotoxins. This denomination classifies
all substance derived from free mycotoxin, that is, all toxic substance originated by
the secondary metabolism of fungi, which through a biological process (human, ani-
mal metabolism or even through the defense mechanism of plants) or technological
process (food processing), have their structure altered as well as polarity, solubility,
and molecular mass, originating a new substance with characteristic toxicity or able
to reinforce the damages caused by parental mycotoxin [45, 46].
Some examples of modified mycotoxins are N-(1-deoxy-D-fructos-1-yl)-
fumonisin B1 (NDF-FB1) and N-(carboxymethyl)-fumonisin B1 (NCM-FB1)
formed in a Maillard reaction between fumonisins and reducing sugars and reaction
of reduction occurring in DON when animal feed is treated with sodium bisulfite
generating sulfonated DON [46].

5. Prevention and control of mycotoxins

Cereals, grains, and oilseed are often infected by insects and toxigenic fungi
when still in the field interfering directly in the quality and productivity of food.
Controlling fungi infestations is not an easy task for involving climatic and environ-
mental issues which frequently cannot be controlled by men. Therefore, it is crucial
to disseminate and implement techniques for good agricultural practices, indis-
pensable to minimize problems related to the production of mycotoxins and quality
of the food in the field. Some of these techniques involve choosing the variety to be
cultivated by preferring lineages that are more resistant to attacks of plagues and
microorganisms, good soil preparation, and turnover of cultures. It is also impor-
tant to rationally employ agricultural pesticides by replacing them with sustainable
techniques for plague control whenever possible, such as biological products, oils,
and natural extracts, seeking to protect the cultivation and the environment [47].
The crop at the correct maturation point and the regulation of agricultural
implements to soften mechanical damages to beans and grains are factors which
combined with good storage practice can reduce fungus infestations in food
products. The main storage practices encompass the improvement of the products
received by removing impurities derived from the field, the control of moisture
through drying process at recommended levels, good ventilation, cleansing of the
storage location, and control of insects and rodents, in addition to a system to rela-
tive air humidity.
In addition to good agricultural and storage practices, some strategies for the
detoxification of food and feed contaminated with mycotoxins have emerged as an
effort to reduce or eliminate their toxic effects through chemical, physical, and bio-
logical methods. Some of them involve the application of gamma irradiation, ozone
(O3), and some microbial strains and fungus parasites able to inhibit the production
or decrease the toxicity of some secondary metabolites like Streptomyces rimosusand
and Gliocladium roseum, respectively. These methods are essential to improve food
safety, prevent economic losses, and retrieve contaminated products [48, 49].

6. Conclusion

Mycotoxins are a group of fungal secondary metabolites, and their produc-

tion is influenced by both the genotype of the organism and the physicochemical

9
Cell Growth

environment in which it is growing. Even if a strain of mold has the genetic poten-
tial to produce a particular mycotoxin, the level of production will be influenced
by the nutrients available. Even when the nutritional requirements are suitable
for mycotoxin biosynthesis, physical parameters, such as temperature and water
activity, will influence production. In nature there are many other factors inter-
acting with the growth and metabolism of a mold. There may be, for example,
antimicrobial agents produced by other microorganisms, by the plant on which
the mold is growing, or added as biocides during crop husbandry. Mycotoxins have
attracted worldwide attention not only because of their perceived impact on human
health but also because of the economic losses accruing from contaminated foods.
Mycotoxins have been extensively studied as well as their impact on human health.
It is clear that food contaminated with toxic substances are not proper for either
human or animal consumption. Considering that mycotoxins are natural contami-
nants and practically impossible to be completely eliminated from food, interna-
tional food safety organizations provide guidance on the serious risks of mycotoxins
to human health by updating and establishing safe levels of ingestion for these
toxins. As a short-term solution, methods of prevention and food detoxification
have been offered to producers aiming at providing means to enlarge the availability
of safe food to the population worldwide.

Author details

Márcia Regina Ferreira Geraldo Perdoncini1*, Maria Josiane Sereia1,

Fabio Henrique Poliseli Scopel1, Maysa Formigoni1, Eliane Sloboda Rigobello1,
Stéfani Caroline Beneti1, Flavia Aparecida Reitz Cardoso1, Livia Benossi Marchi2,
Claudio Gomes da Silva Junior2, Paula Gimenez Milani Fernandes2,
Tuan Henrique Smielevski de Souza2, Priscila Wielewski2, Erica Gomes de Lima2,
Angelivia Gregório2, Maria Rosa Trentin Zorzenon2, Juliana Cristina Castro2,
Vanessa de Cássia Mendes Del Bel2, Magali Soares dos Santos Pozza2
and Leila Larisa Medeiros Marques1

1 Federal University of Technology, Paraná, Brazil

2 State University of Maringa, Paraná, Brazil

*Address all correspondence to: mperdoncini@gmail.com

© 2019 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms
of the Creative Commons Attribution License (http://creativecommons.org/licenses/
by/3.0), which permits unrestricted use, distribution, and reproduction in any medium,
provided the original work is properly cited.

10
Growth of Fungal Cells and the Production of Mycotoxins
DOI: http://dx.doi.org/10.5772/intechopen.86533

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