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death in mice. Pharmacologically, penicillic acid di-

lates blood vessels and has antidiuretic effects. How-

ever, penicillic acid is similar to patulin in its rapid

reaction with sulfhydryl-containing compounds in

foods to form nontoxic products. Penicillic acid is

produced by strains of A. ochraceus and related

species and Penicillium aurantiogriseum and other

species. Some strains of A. ochraceus are capable of

producing penicillic acid along with ochratoxin A.

Penicillic acid has been found in large quantities in

corn with a high moisture content stored at low

temperatures.

Cyclopiazonic Acid

0011 Cyclopiazonic acid (CPA) is produced by several

molds that commonly occur on agricultural com-

modities or are used in certain food fermentations

(Figure 6). CPA has been reported to be produced by

A. flavus, A. versicolor,andA. tamarii as well as

several Penicillium species, some of which are used

in the production of fermented sausages in Europe.

Other molds used in the food fermentations that

have been reported to produce CPA are Penicillium

camemberti, used to produce Camembert cheese, and

Aspergillus oryzae, used to produce fermented soy

sauces. CPA has been reported naturally occurring

in corn and peanuts, and a type of millet (kodo) that

reportedly caused a human intoxication in India. It is

also possible that CPA was involved along with afla-

toxins in ‘turkey X’ disease in England in 1960, since

some isolates of A. flavus produced both aflatoxins

and CPA. CPA has been shown to affect rats, dogs,

pigs, and chickens. Clinical signs of intoxication

include anorexia, diarrhea, pyrexia, dehydration,

weight loss, ataxia, immobility, and extensor spasm

at time of death. Histopathological changes in CPA-

exposed animals include alimentary tract hyperemia,

hemorrhage, and focal ulceration. Focal necrosis can

be found in liver, spleen, kidneys, pancreas, and myo-

cardium. In broiler chicks given CPA, skeletal muscle

degeneration characterized by myofibular swelling

and fragmentation has been observed. About 50%

of a dose of CPA given orally or intraperitoneally to

rats or chickens is distributed to skeletal muscle

within 3 h. CPA has the ability to chelate metal

cations. Chelation of such cations as calcium, magne-

sium, and iron may be an important mechanism of

toxicity of CPA.

Mycophenolic Acid, b-Nitropropionic Acid,

Tremorgens (Penitrem), and Rubratoxin

0012Many toxic compounds have been obtained from

mold cultures; however, not all have been shown to

cause disease in humans or animals. Other myco-

toxins such as mycophenolic acid, b-nitropropionic

acid, and tremorgens have been reported but have not

been studied extensively. Tremorgenic mycotoxins

called penitrems have been reported to have caused

poisonings of dogs that consumed moldy cream

cheese, moldy walnuts, and other moldy debris

(Figure 7). The toxins caused severe muscle tremors,

uncoordinated movements, and generalized seizures

and weakness in the dogs. The disease can also occur

in cattle, where it is called staggers. Tremorgenic

mycotoxins can be produced by fungi in the genera

Aspergillus, Penicillium, Claviceps, and Acremonium.

Mycophenolic acid (Figure 8) and b-nitropropionic

acid have been associated with cheeses produced in

Europe and are believed to be antibiotic substances of

low oral toxicity. Rubratoxin B (Figure 9) produced

hepatic degeneration, centrilobular necrosis, and

hemorrhage of the liver and intestine when given to

experimental animals. However, no natural occur-

rence of disease caused by this toxin has been

documented, though it is suspected of causing a hepa-

totoxic, hemorrhagic disease of cattle and pigs fed

fig0006 Figure 6 Chemical structure of cyclopiazonic acid.

fig0007Figure 7 Chemical structure of penitrem A.

OCH

COOH

fig0008Figure 8 Chemical structure of mycophenolic acid.

4084 MYCOTOXINS/Classifications

moldy corn. Rubratoxin is produced by Penicillium

rubrum and may exert a synergistic effect with

aflatoxins.

Zearalenone

0013 Zearalenone (Figure 10), an estrogenic compound

also known as F-2 toxin, causes vulvovaginitis and

estrogenic responses in swine. Zearalenone is pro-

duced by Fusarium species. Zearalenone has been

found to occur naturally in corn with a high moisture

content in late autumn and winter, primarily from the

growth of Fusarium graminearum and Fusarium

culmorum. Although the compound is not especially

toxic, 1–5 p.p.m. is sufficient to cause physiological

responses in swine. Zearalenone can be transmitted

to piglets in sows’ milk and cause estrogenism in the

young pigs. Zearalenone has been found in moldy

hay, high-moisture corn, corn infected before harvest,

and pelleted feed rations. The involvement of zeara-

lenone in human toxicoses has not been confirmed,

but it is classified as an endocrine disrupter and is

considered potentially hazardous for humans. The

formation of zearalenone is favored by high humidity

and fluctuating temperatures, followed by low tem-

peratures. These conditions often occur in temperate

regions during autumn harvest.

Trichothecenes

0014 Trichothecenes (Figure 11) are a family of closely

related compounds produced by several Fusarium

species. There are more than 20 naturally occurring

compounds produced by Fusarium species, which

have similar structures, including T-2 toxin,

diacetoxyscirpenol, neosolaniol, nivalenol, diacetyl-

nivalenol, deoxynivalenol (DON, vomitoxin), HT-2

toxin, and fusarenon X. DON has been implicated in

a disease known as moldy corn toxicosis of swine,

symptoms of which include refusal to eat (refusal

factor), lack of weight gain, digestive disorders, and

diarrhea, ultimately leading to death. T-2 toxin is

quite toxic to rats, trout, and calves. Large doses of

T-2 toxin fed to chickens result in severe edema of the

body cavity and hemorrhage of the large intestine,

along with neurotoxic effects, oral lesions, and,

finally, death. T-2 toxin is also thought to be one of

the toxins involved in the human disease alimentary

toxic aleukia (ATA) and has been implicated as a

component of the so-called ‘yellow rain’ samples col-

lected from South East Asia in the early 1980s. T-2

toxin causes severe dermal responses in rabbits, rats,

and other animals, including humans, when applied

to the skin. However, it is not thought to be carcino-

genic. Although T-2 toxin is very toxic, its natural

contamination in foods and feeds appears to be low.

Deoxynivalenol causes vomiting in animals and has

been suspected as a cause of foodborne illness in India

in which nausea, vomiting, and diarrhea were the

symptoms. Short-term feeding trials with animals

suggest low acute toxicity, but other evidence indi-

cates that deoxynivalenol may have a teratogenic

potential. Unlike T-2 toxin, deoxynivalenol contam-

ination in commodities, especially wheat and corn, is

significant in certain years. Deoxynivalenol is pro-

duced by F. graminearum and F. culmorum and is

the most commonly occurring trichothecene. The tri-

chothecenes are also of concern because chronic ex-

posure to low levels of these compounds may cause

immunosuppression or immunostimulation-like ill-

nesses in humans and animals.

Fumonisins

0015Fumonisins (Figure 12) are a group of compounds

produced primarily by Fusarium verticillioides (for-

merly known as Fusarium moniliforme)and

F. proliferatum. In animals, fumonisins have been

shown to cause several diseases such as equine leu-

coencephalomalacia, porcine pulmonary edema, and

liver cancer in rats. While not as potent a liver car-

cinogen as aflatoxins, it has been suggested that the

lifetime carcinogenic potential of fumonisin B

in the

rat falls somewhere between carbon tetrachloride and

dimethylnitrosamine. In terms of human disease,

fumonisins are of concern because they have been

linked to esophageal cancer. It has been shown that

there is a significant correlation between the

10'

11'

fig0010 Figure 10 Chemical structure of zearalenone.

14 15 −19

(CH

fig0009 Figure 9 Chemical structure of rubratoxin B.

MYCOTOXINS/Classifications 4085

- CH

- CH - CH - CH - CH

- CH - CH

- CH

- CH - CH

- CH - CH - CH

OHOH

NHR

Fumonisin A

= COCH

CH(CO

H)CH

H; R

= OH; R

= C

Fumonisin A

= COCH

CH(CO

H)CH

H; R

= H; R

= COCH

Fumonisin B

= COCH

CH(CO

H)CH

H; R

= OH; R

= H

Fumonisin B

= COCH

CH(CO

H)CH

H; R

2 =

= H

20 18

21 22

15 14 10 5 3 2 1

fig0012 Figure 12 Chemical structures of fumonisins.

CHCH

OAc

CHCH

OAc

T-2

T-2 Tetraol

OAc

Fusarenon X

HT-2

OAc

Monoacetoxyscirpenol

Deoxynivalenol

Diacetoxyscirpenol

Neosolaniol

fig0011 Figure 11 Chemical structure of several trichothecenes.

4086 MYCOTOXINS/Classifications

consumption of corn contaminated with F. ver-

ticillioides and fumonisins and esophageal cancer in

humans in the Transkei region of South Africa. Fumo-

nisins and F. verticillioides have also been linked to

corn (maize) consumption and a high incidence of

esophageal cancer in certain provinces of northern

China. F. verticillioides commonly occurs in corn-

growing regions of the world and has been said to

be found virtually everywhere that corn is grown.

F. verticillioides invades the corn plant and can exist

there as an endophyte, and may not be evident as a

surface contaminant or infestation. Infection of the

corn kernel by F. verticillioides may occur by invasion

through the silk, fissures in the kernel pericarp and/or

through systemic infection of the plant.

Moniliformin

0016 Moniliformin (Figure 13) was first reported to be

produced by F. moniliforme isolated from corn.

While the toxin apparently was named after this or-

ganism, the name has turned out to be a misnomer,

since subsequent work has shown that most strains of

F. moniliforme (now called F. verticillioides) do not

produce moniliformin, or are only weak producers.

The toxin is produced by F. proliferatum and

F. subglutinans, as well as other Fusarium species.

Moniliformin is highly toxic when given orally to

experimental animals, causing rapid death without

severe cellular damage. One-day-old cockerels and

mice have been shown to be quite sensitive to the

toxin. Clinical lesions observed include acute degen-

erative lesions in the myocardium and other tissues.

Moniliformin has also been suggested as a possible

cause of Keshan disease, a human myocardial impair-

ment occurring in rural areas of China and South

Africa where there is a high consumption of corn

(maize) that has been shown to be contaminated

with moniliformin.

Potential Toxicity of

Penicillium roqueforti

0017 Penicillium roqueforti has been shown to produce

several toxic compounds, including roquefortine,

PR toxin, and festuclavine (Figure 14). Toxicities of PR

toxin and roquefortine are low. Roquefortine is a

neurotoxin that reportedly causes convulsive seizures,

liver damage, and hemorrhage in the digestive tract

in mice. However, repeated studies have failed to

reproduce these results. Roquefortine has been re-

covered from blue cheese and was associated with

the mold mycelia rather than the nonmoldy areas of

the cheese. A toxic factor in the fat of Roquefort

cheese that caused severe injury to the liver and

other organs of rats has been reported. Atypical,

wild strains of P. roqueforti have been shown to

produce patulin and penicillic acid simultaneously,

patulin alone, patulin plus citrinin, and mycophenolic

acid. The significance of the various toxins produced

by P. roqueforti to public health is not clear. Patulin,

penicillic acid, and citrinin have been observed only

in wild-type isolates of the organism and not in com-

mercial strains, nor in any cheese produced by com-

mercial strains. As such, the wild isolates represent

no greater significance than any other toxinogenic

isolates of other species. The significance of PR

toxin, mycophenolic acid, the roquefortines, and re-

lated alkaloids to human health is likewise unclear,

−

fig0013 Figure 13 Chemical structure of moniliformin.

OCO

CHO

COO

N−CH

Roquefortine A

N−CH

Roquefortine B

1617

PR-toxin

fig0014Figure 14 Chemical structures of some P. r o q u e f o r t i toxins.

fig0015Figure 15 Chemical structure of tenuazonic acid.

MYCOTOXINS/Classifications 4087

particularly in view of the limited toxicological infor-

mation available on these compounds. PR toxin ap-

parently reacts with cheese components and is

neutralized. The fact that blue-veined cheeses have

been consumed for centuries without any apparent

ill effect suggests that the hazard to human health is

minimal or nonexistent. (See Alkaloids: Properties

and Determination.)

Alternaria Toxins

0018 Alternaria species, including A. alternata, A. citrii, A.

tenuissima, and others produce several toxic com-

pounds, alternariols, altenuene, tentoxin and tenua-

zonic acid (Figure 15). These organisms are common

in many foods and grains. Alternaria species require

high-moisture conditions and tend to be found in

foods that are high in moisture such as grains prior

to harvest and fruits and vegetables. The Alternaria

toxins can be found in grains when drying in the field

and harvest are delayed by rain, high humidity, or

early frost. Alternaria species are most common in

sorghum grain, but the toxins have only been found in

heavily weathered sorghum. Postharvest occurrence

of Alternaria species in fruits and vegetables is more

common because the moisture content remains high

after harvest. Alternaria infection of fruits and vege-

tables has been observed in apples, oranges, toma-

toes, and bell peppers. Alternaria toxins have been

detected in oranges, tomatoes, tomato paste, and

commercial apple products. Alternaria toxins are

toxic to Bacillus mycoides and HeLa cells. The

toxins, however, are only weakly toxic to mice and

do not appear to be toxic to rats or chicks when

administered as single, purified compounds. There

is some evidence that mixtures of the compounds

may be more toxic. The Alternaria toxins are also

phytotoxins which affect various plants. Alternaria

alternata f. sp. lycopersici, which is a pathogen

of tomatoes, produces a host specific phytotoxin

known as AAL toxin which is nearly identical in

structure to fumonisins.

Ergot

0019 Ergot is a disease of plants, particularly small grains

such as rye and barley and other grasses, which is

caused by species of Claviceps, in particular

C. purpurea, C. paspalli, and C. fusiformis. These

fungi invade the female sex organs of the host plant

and replace the ovary with a mass of fungal tissue

known as a sclerotium. The sclerotia, also called

ergots, are about the same size and density as the

grain kernels and tend to go with the grain when

harvested. The sclerotia contain alkaloids that are

produced by the fungus. The alkaloids ergotamine

(Figure 16), ergosine, and others are derivatives of

lysergic acid, and cause disease in animals and

humans. The disease is manifested by a sensation of

cold hands and feet followed by an intense burning

sensation. As the disease progresses, the extremities

may become gangrenous and necrotic, and in

animals, sometimes the extremities are sloughed. In

severe cases, death may ensue. Ergotism, also known

as St. Anthony’s fire, reached epidemic proportions

during the Middle Ages. At that time, the cause of the

disease was not known, but it was most probably

associated with bread made from flours of rye and

other grains that were infested with ergot sclerotia. In

recent times, outbreaks involving humans have oc-

curred in Africa and India. Outbreaks of animal poi-

sonings still occur in areas where rye, barley, and

other susceptible small grains and grasses are grown.

Stability of Mycotoxins in Foods

0020Most of the information on mycotoxin contamin-

ation of commodities concerns agricultural products

such as grain (Table 1). Therefore, much of what is

known about the stability of mycotoxins pertains to

the effects of storage, food processing, and cooking.

Aflatoxins tend to be stable to moderately stable

during storage under most conditions and in most

food processes. Various food processes can reduce

the amount of aflatoxin by destruction or removal,

but usually, some percentage of the toxin will persist

and carry into the finished food. Aflatoxins are stable

in peanut materials at room temperature, but are

partially destroyed by roasting; however, destruction

is not complete. In the wet milling of corn, aflatoxin,

if present, will be found primarily (over 97%) in the

steep water and fiber fractions, but little (1% or less)

in the starch. Aflatoxins may be reduced in the baking

process, but are not completely destroyed. The manu-

facture of corn flakes has been shown to reduce

aflatoxin levels in flaking grits by 75–80%. Similarly,

some sterigmatocystin will be lost during roasting of

coffee beans, but some will also remain. Ochratoxin

is not eliminated from grain by cleaning or milling,

after which it appears equally divided between flour

and bran fractions. Ochratoxin will persist through

fig0016Figure 16 Chemical structure of ergotamine.

4088 MYCOTOXINS/Classifications

the baking process, manufacture of corn flakes and

through the cooking of mash for beer. However,

roasting of green coffee beans has been shown to

completely destroy ochratoxin. Patulin and penicillic

acid appear to be moderately stable in processed

apple products but are unstable in grains, grain-

based foods, meats, and cheese. Patulin and penicillic

acid react with sulfydryl and amino compounds to

form nontoxic adducts. Patulin also appears to be

destroyed by the alcoholic fermentation of apple

juice and by wine-making. Deoxynivalenol (DON)

in wheat milled into flour will be found primarily in

the bran fraction but is not destroyed. Also, baking

does not destroy DON, though there may be some

reduction of DON levels. Likewise, extrusion pro-

cessing of cereal grains may give some reduction of

DON under conditions of high temperatures and

pressures. In the wet milling of zearalenone-contam-

inated corn, like aflatoxins, zearalenone concentrates

in the fractions used for animal feed and not in the

starch. Likewise, in wet milling of T-2 toxin-contam-

inated corn, most of the T-2 toxin is found in the steep

water, germ, gluten, and fiber, and only 6–8% is

found in the starch. Extrusion processing of corn

(maize) contaminated with zearalenone has been

shown to reduce zearalenone concentrations by 65–

83%. Ethanol fermentation of fumonisin-contamin-

ated corn results in little degradation of fumonisin

during fermentation, with most of the toxin being

found in the distillers’ grains, thin stillage and distil-

lers’ solubles fractions. None of the fumonisin is

found in the distilled alcohol. Fumonisins are stable

in baked or canned corn (maize) products, with little

or no loss. Roasting at temperatures above 200



result in apparent loss of fumonisins, whereas the

corn flake process and extrusion processing result in

low to moderate reductions of fumonisins. However,

if glucose is added, the reduction of fumonisins

increases dramatically to more than 80% in both the

corn flake process and extrusion processes. Thus, in

most cases, mycotoxins are not completely destroyed

by processing and cooking. Some destruction occurs,

the extent of which depends on the process and the

toxin present, though destruction usually is not com-

plete. Also, mycotoxins may tend to concentrate in

certain fractions during milling and fermentation,

depending upon the type of mycotoxin and process

used.

See also: Aflatoxins; Alkaloids: Properties and

Determination; Carcinogens: Carcinogenic Substances

in Food: Mechanisms; Cereals: Dietary Importance; Food

Safety; Immunology of Food; Mutagens; Mycotoxins:

Occurrence and Determination; Toxicology; Spoilage:

Molds in Spoilage

Further Reading

Betina V (ed.) (1984) Mycotoxins: Production, Isolation,

Separation and Purification. New York: Elsevier.

Betina V (ed.) (1989) Mycotoxins: Chemical, Biological

and Environmental Aspects. New York: Elsevier.

Bullerman LB (1986) Mycotoxins and Food Safety. A

Scientific Status Summary by the Institute of Food

Technologists’ Expert Panel on Food Safety and

Nutrition. Chicago, IL: Institute of Food Technologists.

Bullerman LB (2000 Fusaria and toxigenic molds other

than aspergilli and penicillia. Chapter 23. In: Doyle

MP, Beuchat LR and Montvile TJ (eds) Food Microbiol-

ogy: Fundamentals and Frontiers. Washington, DC:

ASM Press.

CAST (2000) Mycotoxins. Risks and Impacts in Plant and

Animal Systems. Ames, IA: Council for Agricultural

Science and Technology.

Eaton DL and Groopman JD (eds) (1994) The Toxicology

of Aflatoxins, Human Health, Veterinary and Agricul-

tural Significance. New York: Academic Press.

International Agency for Research on Cancer (1987) Afla-

toxins. In: IARC Monograph on the Evaluation of

Carcinogenic Risks to Humans, Supplement 7, pp. 83–

87. Lyon: IARC.

Jackson LS and Bullerman LB (1999) Effect of processing

on Fusarium mycotoxins. Advances in Experimental

Medicine and Biology 459: 243–261.

LeBars J and Galtier P (eds) (1998) Mycotoxins in the food

chain: processing and toxicological aspects. Revue d

Elevage et de Medecine Veterinaire des Pays Tropicaux

149: 469–715.

Miller JD and Trenholm HL (eds) (1994) Mycotoxins in

Grain. Compounds Other Than Aflatoxins. St. Paul,

MN: Eagan Press.

Sharma RP and Salunkhe DK (eds) (1991) Mycotoxins and

Phytoalexins. Boca Raton, FL: CRC Press.

Sinha KK and Bhatnagar D (eds) (1998) Mycotoxins in

Agriculture and Food Safety. New York: Marcel Dekker.

Smith JE and Henderson RS (eds) (1991) Mycotoxins and

Animal Foods. Boca Raton, FL: CRC Press.

Occurrence and Determination

A Chrevatidis, Eclipse Scientific Group, Chatteris,

Cambs, UK

Occurrence

0001The name mycotoxin is a compound word derived

from the Greek mykes, which means fungus (mold),

and the Latin toxicum, which means poison. From

early on, fungi were used in food preservation and

processing, producing particular flavors and taste in

products like cheese and soy sauce. They are also

MYCOTOXINS/Occurrence and Determination 4089

producers of antibiotics and other useful chemicals.

On the other hand, such species have been linked with

a number of toxic outbreaks around the world, caus-

ing serious illnesses and even death. They have been

discovered after the outbreak of ‘St Anthony’s fire,’

when a large number of people died in Russia in

the early 1900s after the consumption of rye contam-

inated with ergot alkaloids produced by the mold

Claviceps purpurea. In their despair, due to a tremen-

dous burning sensation and epileptic fits, many pil-

grims travelled to St Anthony’s shrine in France

hoping for a cure.

0002 During the last 40 years of research on mycotoxins,

hundreds have been discovered but it is fortunate that

a relatively small number has been proven to be

harmful. Although the number is limited, it is import-

ant to bear in mind that a number of agricultural

products are susceptible and the fungi infesting them

are capable of producing amounts of toxins able to

cause devastating effects.

0003 Mycotoxins are toxic secondary metabolites

(byproducts) occurring naturally by several fungal

species under various climatic conditions on a large

number of agricultural commodities. The reason for

their existence is not quite clear; however, it has been

suggested that they are produced under adverse con-

ditions or that they may play a role in the survival of

the fungus itself. Spores of these fungi exist in the air

and soil throughout the world and can germinate

when appropriate conditions arise. Mycotoxins can

be formed in the field prior to and after harvest during

inappropriate storage. More specifically, mycotoxin

occurrence is due to several factors:

0004 Biological: crop susceptibility and fungus com-

patibility;

0005 Environmental: temperature, moisture, mechan-

ical injury, insect damage, fungus;

0006 Harvesting: crop maturity, temperature, moisture,

detection/diversion;

0007 Storage: temperature, moisture, detection/diver-

sion;

0008 Distribution/processing: detection/diversion.

Mycotoxins are a reason for concern because they

affect the economy and health status of the world

population. It has been estimated that approximately

25% of the world’s grain is lost annually as a result of

contamination by mycotoxins leading to produce

being destroyed, dumped, or degraded, therefore,

causing heavy financial burden on the exports of

many developing and developed countries. Some

Asian, African, and Latin American countries whose

economy strictly relies on agricultural commodities

can suffer dramatically when their consignments are

denied export. These losses can vary from year to year

depending on the environmental conditions, which

entirely depend on nature. They are also a significant

burden to the farming industry by reducing the

growth rate and reproductive efficiency of animals

as well as condemning meat and dairy products. The

health implications associated with mycotoxins are

numerous, and include acute toxicity outbreaks and

chronic cases of disease. Acute effects such as death

are caused by the ingestion of high amounts of the

toxin in a given short time period; such cases have

been recorded in Asia, India, and Africa, where qual-

ity control of food may be compromised. Chronic

effects are a more serious matter, as is a type of

exposure that can take place more frequently. It is

caused by the long-term ingestion of low levels of

the toxin; such exposure has been associated with

increased risk of primary liver carcinoma in Asia.

Further health effects caused by exposure to myco-

toxins are allergies and infections.

0009Mycotoxins are very stable at high temperatures

with little or no destruction occurring under the

conditions of ordinary cooking or conventional

processing. As a result they have repeatedly been

detected in many final products. Consumption of

contaminated foods is considered the main route of

exposure to mycotoxins, and this must be avoided.

Table 1 provides an overview of the most frequently

occurring mycotoxins, their fungal source, and the

foods susceptible to infestation.

Aflatoxins

0010A single event in the UK in 1960 established the

significance of mycotoxins. During this outbreak

thousands of turkeys, ducklings, and chicks died as

a result of Turkey X disease. Chemical analysis by

thin-layer chromatography (TLC) identified several

ultraviolet (UV) fluorescent compounds in the feed

(Brazil peanut meal) which were thought to be re-

sponsible for this outbreak. These compounds were

named aflatoxins. Aflatoxins are produced primarily

by the Aspergillus genera, and more specifically by

A. flavus, A. parasiticus, and A. nonius, which are

ubiquitous in the environment and infest a large

variety of commodities. Within the aflatoxin family,

aflatoxin B

(AFB

) is the most acutely and chronic-

ally toxic, carcinogenic, and mutagenic of all. There is

sufficient epidemiological evidence to support the

carcinogenic properties of AFB

to humans and

animals and therefore to lead to its classification as

a class 1 carcinogen by the International Agency for

Research on Cancer (IARC).

0011To date, a total of 20 compounds have been desig-

nated as aflatoxins with AFB

, AFB

, AFG

, and

AFG

the most significant and common food contam-

inants. Aflatoxin M

and M

are metabolites of AFB

4090 MYCOTOXINS/Occurrence and Determination

and AFB

excreted in milk and urine of ruminants

that have consumed contaminated feeding stuffs. Af-

latoxins are produced when food is stored for long

periods of time under high temperature and humidity.

Seasonal variation has been found to affect myco-

toxin levels, while regional variations due to the cul-

tural habits of storing the food are usually considered

as secondary factors. The occurrence of aflatoxins in

foods and feeds has been reported in several countries

and, although it is greatest in the warmest and humid

parts of the world like Asia, Africa, and South Amer-

ica, it is also an annual problem to some degree in

areas of the USA and Europe. Agricultural commod-

ities rich in lipids and carbohydrates are susceptible

to aflatoxin contamination and such raw ingredients

include cereals, rice, pulses, oilseeds, dry fruits, spices,

nuts (peanuts, Brazil, and pistachios) and animal-

derived products (i.e., milk, eggs). Aflatoxins were

also detected in Indian chilli powder, capsicum pepper,

nutmeg, and dried chilli peppers. Recent evidence has

revealed that aflatoxins have been detected in heroin

and marijuana samples, compromising even further

the health status of drug-dependent individuals.

Since aflatoxins are very stable, food-processing tech-

niques like pasteurization or sterilization may not be

effective in removing the toxin from its natural sub-

strate and as a consequence may be detected in the

final product. Epidemiological evidence in Asian and

African countries has revealed a positive correlation

between exposure to aflatoxins and primary liver

carcinoma in humans. In order to protect the con-

sumer from such a potent food contaminant, the Food

and Drug Administration (FDA) in the USA has set

action levels for the presence of aflatoxins in foods

ranging from 0.5 p.p.b. (for AFM

in milk) to 20

p.p.b. for total aflatoxins in other food. In Europe,

the European Commission (EC) has set lower levels of

0.05 p.p.b. and 15 p.p.b. for milk and other foods

respectively, while new legislation has set limits of 10

p.p.b. for total aflatoxins in spices.

Ochratoxin A

0012Ochratoxin A (OTA) is the most commonly encoun-

tered and important of the group. It is produced

mainly by Penicillium verrucosum under temperate

climatic conditions of Eastern and South Europe,

tbl0001 Table 1 The most important mycotoxins produced by fungal species in various agricultural commodities

Mycotoxin Fungal species Commodities

Aflatoxins B

Aspergillus flavus Nuts, cereals, pulses, spices, soybeans, dried fruit, cottonseed

A. parasiticus

A. nomius

Aflatoxins M

and M

Metabolic products of B

and B

Milk

Ochratoxin A A. ochraceus Grains, coffee, wine, beer, dried fruit

Penicillium verrucosum

Patulin P. e x p a n s u m Apples, plums, peaches, pears, and vegetables

A. clavatus

Byssochlamys nivea

Trichothecenes Fusarium sporotrichoides Wheat, barley, corn, oats, rye

F. graminearum

F. verticilloides

F. n i v a l e

Stachybotrys

Trichoderma

Zearalenone Fusarium culmorum Corn, wheat, barley, rice

F. graminearum

F. crookwellense

Fumonisins F. m o n i l i f o r m e Corn/maize, grains

F. p r o l i f e r a t u m

Cyclopiazonic acid P. cyclopium Cheese, cereals, pulses, nuts

A. flavus

A. versicolor

Moniliformin F. moniforme Cereals

F. sporotrichoides

Sterigmatocystin A. nidulans Cereals, cheese

A. versicolor

Citrinin P. citrinum Wheat, barley, rice, rye, oats

P. verrucosum

A. oryzae

Penicillic acid P. cyclopium Corn, beans, apples

P. puberculum

MYCOTOXINS/Occurrence and Determination 4091

Canada, and South America. It is also of great

concern to the Baltic states and Scandinavia as the

local cereals grown (barley and oats) are particularly

susceptible to high levels of ochratoxin contamin-

ation. Aspergillus ochraceus has been associated

with the production of OTA in tropical areas of the

world. The most frequently contaminated commod-

ities are wheat, nuts, and corn, while a number of raw

and processed commodities have been found to be

contaminated by OTA; some of these are coffee,

beer, wine, dried fruit, cocoa, and green coffee.

Water activity of foods is important for the growth

of fungi, therefore storage under dry conditions is

critical. Similarly to aflatoxins, ochratoxin A is a

moderately stable molecule and will survive most

food processes, thus it is important that it is absent

in the raw materials used. It is also important to

highlight that ochratoxin is a regular contaminant

of a large number of feeding stuffs, therefore contam-

ination is transferred to animals such as swine and

poultry. As a result humans are exposed directly by

consumption of contaminated foods, as well as indir-

ectly by consuming various animal tissues of an

affected animal.

0013 OTA is a potent toxin targeting the kidney and

causing acute and chronic lesions, while associations

have been made with Balkan endemic nephropathy

on various parts of the world. As a result of its

potency, it has been classified as a class 2B (potential)

carcinogen by the IARC. To date, the EC has set legal

limits for the presence of OTA in various food groups

ranging from 3 to 10 p.p.b. for cereal products and

dried vine fruit respectively.

Patulin

0014 Patulin is a secondary metabolite of certain Penicil-

lium, Aspergillus,andByssochlamys species but,

more specifically, P. expansum appears to be the

fungus responsible for patulin production. It is a

common contaminant of apples and apple products

but commodities such as grains and other fruits and

vegetables are also susceptible although to a lower

extent. Even though the contamination incidence is

high, it is fortunate that the levels are usually low.

Refrigeration temperatures are shown to be ideal for

the production of patulin by several fungi, thus long

storage periods must be avoided. The presence of

patulin in apple juice is evidence that rotten fruit

were being used; however, it is fairly easy to avoid

contamination as most of the toxin is located in the

rotten part of the fruit and once it has been removed,

the problem is minimized. Juice fermentation also

results in a 99% destruction of the toxin. Patulin

has been a reason for concern due to its carcinogenic

properties; however, the IARC was unable to

establish the severity of its effects on humans and

as a consequence no classification exists at present.

Regulation levels set in several countries vary from 30

to 50 mgl

1

. The EC proposed limits of 50 p.p.b. in

apple juice and 25 p.p.b. in solid apple products.

Trichothecenes

0015Trichothecenes are a family of closely related chem-

ical compounds. They are metabolites of the fungi of

Fusarium, Trichoderma, and Stachybotrys. They have

been reported in colder climates of Scandinavia,

Canada, Japan, and a number of European countries,

but they also occur worldwide and in high diverse

geographic regions. The group was discovered in

1932 in the Soviet Union after an acute episode of

alimentary toxic aleukia, which caused 60% mortal-

ity to the exposed population. Among the 50 known

trichothecenes, a limited number appear to be of

importance. According to their chemical characteris-

tics, they have been divided into type A, including

diacetoxyscirpenol, HT-2, neosolaniol and T-2 and

type B trichothecenes including 3-acetyldeoxynivale-

nol, 15-acetyldeoxynivalenol, deoxynivalenol, fusar-

enone-X, and nivalenol. Commodities affected by

Fusarium toxins are oats, rye, cassava, sorghum,

bananas, groundnut, soybeans, mangoes, and many

more. Some of the most commonly produced toxins

are deoxynivalenol (DON), nivalenol (NIV), and dia-

cetoxyscirpenol (DAS) produced by F. graminearum,

F. nivale, and F. sambucinum, while HT-2 and T-2 are

produced by F. tricinctum and F. roseum and are more

rare and the most harmful of the group. DON has

repeatedly been found in corn and wheat as well as

other cereals and is considered the most ambudant

trichothecene produced.

0016Trichothecenes are fairly stable compounds and

can persist for long periods. Evidence has shown

that 50–60% of the toxins are transmitted to the

finished product as processing removes only a small

amount, therefore, there are concerns in regard to

dietary exposure through foods like breakfast cereals,

breads, noodles, beer, and infant foods. Epidemi-

ological data have associated DON ingestion with

human mycotoxicoses in China, India, and Japan

while trichothecenes have been associated with

feed refusal, depression of immune response, nausea,

occasional vomiting, and anemia in humans and

animals. In addition to crops destined for human

consumption, a large number of feeding stuffs have

also been found to be contaminated by the same

toxin; however, transfer to the human food chain

appeared to be minimal. Infestation of crops by the

mold appears red-pink colored, usually located at

the head or tip of the crop. Formation of DON in

the field can vary due to climate and geographical

4092 MYCOTOXINS/Occurrence and Determination

region as well as variations from year to year. In view

of consumer protection, the FDA has set advisory

levels for DON of 1 p.p.m. in foods intended for

human consumption. In Europe, the EC proposed

action levels of 500 and 750 p.p.b. at the retail and

raw material stage respectively.

Zearalenone

0017 Zearalenone (ZEN) is a mycotoxin with estrogenic

properties produced by the field fungi Fusaria. Simi-

larly to the trichothecenes, ZEN is produced under

the same conditions; however, a drop in the tempera-

ture during growth stimulates production of toxins.

In addition to trichothecene production, Fusarium

graminearum and F. culmorum are the primary

fungi responsible for the production of ZEN; how-

ever, eight others can also produce the toxin at vary-

ing amounts. It is the second most commonly

encountered Fusarium metabolite and is known to

contaminate crops such as maize, wheat, barley,

oats, and rye in Canada, the USA, and Japan.

Although there is no epidemiological evidence to sup-

port esophageal cancer development from exposure

to ZEN, an association in certain parts of Africa has

been made. ZEN metabolites have been shown to

transfer into milk; however, the evidence that they

may pose potential risks to humans is limited. It is a

compound that survives processing and fermentation

and, as a result, it has been found not only in animal

feed but products intended for human consumption.

Examples are corn meal, breakfast cereals, beer, and

fermented products.

0018 The ZEN producing fungi usually grow in the field,

causing pink discoloration of the kernel; however it is

not always evidence of the presence of the metabolite.

ZEN is only partly decomposed by heat treatment but

cleaning a crop by removing its outer hull may result

in 40–100% reduction of the toxin. The FDA has not

issued an advisory level for ZEN but observations

should continue. The EC has also urged member

states to monitor ZEN levels in inflant foods and

cereals.

Fumonisins

0019 Similarly to aflatoxins and ochratoxins, fumonisins

are a group of approximately 15 closely related myco-

toxins. They were isolated in 1988 from cultures of

F. moniliforme; however, several other Fusarium

species, including F. proliferatum and F. nygamoni,

are also producers. Among the six members of fumo-

nisins, fumonisin B

(FB

) is the most important as it

is the most frequently occurring and potent of the

group. They mostly occur in maize, with 90% of its

amount produced in the field. Initially it was thought

that their presence was limited to corn products, but

they have also been found in lower concentrations in

rice, sorghum, and navy beans. Fumonisins often

occur together with other mycotoxins such as afla-

toxins, ZEN, and deoxynivalenol and studies on their

toxic interactions are currently under way. Crop in-

festation results in a disease called Fusarium ear rot

and is the most common in the Midwest USA and

around the world in both the northern and southern

hemispheres. In terms of health implications, it has

been associated with esophageal cancer in parts of

South Africa, China, and Northeast Italy. Recently,

the IARC has classified the toxins produced by

F. moniliforme as class 2B (potential) carcinogens.

No advisory level has been set in the USA nor Europe

since there is insufficient evidence on its effects. How-

ever, the EC proposed a maximum daily intake of

2 mgkg

1

body weight (based on rat studies).

Cyclopiazonic acid

0020Aspergillus flavus and various Penicillium species

such as P. cyclopium are responsible for the produc-

tion of cyclopiazonic acid, which has been detected in

crops such as corn and peanuts and in several cheeses.

Feeding stuffs are also commonly contaminated by

cyclopiazonic acid and have been reported to coexist

with aflatoxins in a range of substrates. It has been

implicated in Kodua poisoning in India: this is a dis-

ease causing tremors, sleepiness, and giddiness. As a

mycotoxin it is not well documented because the

existing methods of analysis are not fully developed

and therefore, this precludes a full assessment.

Moniliformin

0021Moniliformin is a mycotoxin which is produced by

a number of Fusarium species, including F. moni-

liforme, F. chlamydosporus, F. anthophilum,and

F. proliferatum. Only a limited number of surveys

have shown that it is a frequent contaminant of

maize and at low levels. It has also been reported to

occur in wheat and rice and limited information exists

about its stability during processing. In humans, a

possible link between moniliformin ingestion and

Keshan disease (a chronic heart condition) in certain

areas of China has been suggested. Therefore, it has

been recommended that food monitoring will con-

tinue to collect data on its frequency and levels of

occurrence.

Sterigmatocystin

0022Sterigmatocystin was first isolated in 1957 from a

mycelial mass of A. versicolor but A. nidulans is

also known to produce it. AFB

has a very similar

structure to sterigmatocystin and it is thought that it

may be derived from it. With the same thought in

mind, it is not accidental that sterigmatocystin has

MYCOTOXINS/Occurrence and Determination 4093