Ochratoxin A
Encyclopedia
Ochratoxin A, a toxin
produced by Aspergillus ochraceus, Aspergillus carbonarius and Penicillium verrucosum, is one of the most abundant food-contaminating mycotoxin
s in the world. Human exposure occurs mainly through consumption of improperly stored food products, particularly contaminated grain
and pork
products, as well as coffee
, wine grapes and dried grapes. The toxin has been found in the tissues and organs of animals, including human blood
and breast milk
. Ochratoxin A toxicity has large species- and sex-specific differences.
There is sufficient evidence in experimental animals for the carcinogenicity of ochratoxin A. Ochratoxin A was tested for carcinogenicity by oral administration in mice and rats. It increased the incidence of hepato-cellular (Hepatic tumor) tumours in mice of each sex and produced renal-cell adenomas and carcinomas in male mice and in rats of each sex.
and immunotoxicity in animals. The toxin's immunosuppressant activity in animals may include depressed antibody
responses, reduced size of immune organs (such as the thymus
, spleen
, and lymph node
s), changes in immune cell number and function, and altered cytokine
production. Immunotoxicity probably results from cell death following apoptosis
and necrosis
, in combination with slow replacement of affected immune cells due to inhibition of protein synthesis.
from, urothelial urinary tract tumours. However, there is currently insufficient information to conclusively link ochratoxin A to Balkan endemic nephropathy. The toxin may require synergistic interactions with predisposing genotypes or other environmental toxicants to induce Balkan endemic nephropathy.
industry. Chickens, turkeys and ducklings are susceptible to this toxin
. Clinical signs of avian
ochratoxicosis are similar to other toxins and generally involve reduction in weight gains, poor feed conversion, reduced egg production, poor egg shell quality and kidney poisoning.
Acute toxicity does not seem to constitute a problem in cattle.
Toxin
A toxin is a poisonous substance produced within living cells or organisms; man-made substances created by artificial processes are thus excluded...
produced by Aspergillus ochraceus, Aspergillus carbonarius and Penicillium verrucosum, is one of the most abundant food-contaminating mycotoxin
Mycotoxin
A mycotoxin is a toxic secondary metabolite produced by organisms of the fungus kingdom, commonly known as molds. The term ‘mycotoxin’ is usually reserved for the toxic chemical products produced by fungi that readily colonize crops...
s in the world. Human exposure occurs mainly through consumption of improperly stored food products, particularly contaminated grain
GRAIN
GRAIN is a small international non-profit organisation that works to support small farmers and social movements in their struggles for community-controlled and biodiversity-based food systems. Our support takes the form of independent research and analysis, networking at local, regional and...
and pork
Pork
Pork is the culinary name for meat from the domestic pig , which is eaten in many countries. It is one of the most commonly consumed meats worldwide, with evidence of pig husbandry dating back to 5000 BC....
products, as well as coffee
Coffee
Coffee is a brewed beverage with a dark,init brooo acidic flavor prepared from the roasted seeds of the coffee plant, colloquially called coffee beans. The beans are found in coffee cherries, which grow on trees cultivated in over 70 countries, primarily in equatorial Latin America, Southeast Asia,...
, wine grapes and dried grapes. The toxin has been found in the tissues and organs of animals, including human blood
Blood
Blood is a specialized bodily fluid in animals that delivers necessary substances such as nutrients and oxygen to the cells and transports metabolic waste products away from those same cells....
and breast milk
Breast milk
Breast milk, more specifically human milk, is the milk produced by the breasts of a human female for her infant offspring...
. Ochratoxin A toxicity has large species- and sex-specific differences.
Carcinogenicity
Ochratoxin A is potentially carcinogenic to humans (Group 2B). Ochratoxin A has been shown to be weakly mutagenic, possibly by induction of oxidative DNA damage.There is sufficient evidence in experimental animals for the carcinogenicity of ochratoxin A. Ochratoxin A was tested for carcinogenicity by oral administration in mice and rats. It increased the incidence of hepato-cellular (Hepatic tumor) tumours in mice of each sex and produced renal-cell adenomas and carcinomas in male mice and in rats of each sex.
Immuno suppression and immunotoxicity
Ochratoxin A can cause immunosuppressionImmunosuppression
Immunosuppression involves an act that reduces the activation or efficacy of the immune system. Some portions of the immune system itself have immuno-suppressive effects on other parts of the immune system, and immunosuppression may occur as an adverse reaction to treatment of other...
and immunotoxicity in animals. The toxin's immunosuppressant activity in animals may include depressed antibody
Antibody
An antibody, also known as an immunoglobulin, is a large Y-shaped protein used by the immune system to identify and neutralize foreign objects such as bacteria and viruses. The antibody recognizes a unique part of the foreign target, termed an antigen...
responses, reduced size of immune organs (such as the thymus
Thymus
The thymus is a specialized organ of the immune system. The thymus produces and "educates" T-lymphocytes , which are critical cells of the adaptive immune system....
, spleen
Spleen
The spleen is an organ found in virtually all vertebrate animals with important roles in regard to red blood cells and the immune system. In humans, it is located in the left upper quadrant of the abdomen. It removes old red blood cells and holds a reserve of blood in case of hemorrhagic shock...
, and lymph node
Lymph node
A lymph node is a small ball or an oval-shaped organ of the immune system, distributed widely throughout the body including the armpit and stomach/gut and linked by lymphatic vessels. Lymph nodes are garrisons of B, T, and other immune cells. Lymph nodes are found all through the body, and act as...
s), changes in immune cell number and function, and altered cytokine
Cytokine
Cytokines are small cell-signaling protein molecules that are secreted by the glial cells of the nervous system and by numerous cells of the immune system and are a category of signaling molecules used extensively in intercellular communication...
production. Immunotoxicity probably results from cell death following apoptosis
Apoptosis
Apoptosis is the process of programmed cell death that may occur in multicellular organisms. Biochemical events lead to characteristic cell changes and death. These changes include blebbing, cell shrinkage, nuclear fragmentation, chromatin condensation, and chromosomal DNA fragmentation...
and necrosis
Necrosis
Necrosis is the premature death of cells in living tissue. Necrosis is caused by factors external to the cell or tissue, such as infection, toxins, or trauma. This is in contrast to apoptosis, which is a naturally occurring cause of cellular death...
, in combination with slow replacement of affected immune cells due to inhibition of protein synthesis.
Potential link to Balkan endemic nephropathy
A number of descriptive studies have suggested a correlation between exposure to ochratoxin A and Balkan endemic nephropathy, and have found a correlation between the geographical distribution of Balkan endemic nephropathy and a high incidence of, and mortalityDeath
Death is the permanent termination of the biological functions that sustain a living organism. Phenomena which commonly bring about death include old age, predation, malnutrition, disease, and accidents or trauma resulting in terminal injury....
from, urothelial urinary tract tumours. However, there is currently insufficient information to conclusively link ochratoxin A to Balkan endemic nephropathy. The toxin may require synergistic interactions with predisposing genotypes or other environmental toxicants to induce Balkan endemic nephropathy.
Food animal industry impact
Ochratoxin-contaminated feed has its major economic impact on the poultryPoultry
Poultry are domesticated birds kept by humans for the purpose of producing eggs, meat, and/or feathers. These most typically are members of the superorder Galloanserae , especially the order Galliformes and the family Anatidae , commonly known as "waterfowl"...
industry. Chickens, turkeys and ducklings are susceptible to this toxin
Toxin
A toxin is a poisonous substance produced within living cells or organisms; man-made substances created by artificial processes are thus excluded...
. Clinical signs of avian
Bird
Birds are feathered, winged, bipedal, endothermic , egg-laying, vertebrate animals. Around 10,000 living species and 188 families makes them the most speciose class of tetrapod vertebrates. They inhabit ecosystems across the globe, from the Arctic to the Antarctic. Extant birds range in size from...
ochratoxicosis are similar to other toxins and generally involve reduction in weight gains, poor feed conversion, reduced egg production, poor egg shell quality and kidney poisoning.
Acute toxicity does not seem to constitute a problem in cattle.