Fumonisins Ochratoxins Produced primarily by Fusariun Produced by - PDF document

I ntroduction: FUNGI AND MYCOTOXI NS • “Myco” means mold and “toxin” represents poison Mehrdad Tajkarimi • Mainly low molecular weight proteins • Under proper environmental conditions DVM PhD (temperature, moisture, oxygen …), University of California-Davis mycotoxin levels become high PHR 250 07 Mehrdad Tajkarimi DVM PhD Mehrdad Tajkarimi DVM PhD VMPHR 250 07 UC Davis VMPHR 250 07 UC Davis History: Mycotoxins • Ergotism and mushrom poisoning Some mycotoxins: • Lethal effects • Alimentary toxic aleukia (ATA), with • Cause specific diseases • Effect on the immune system more than 5000 deaths caused by • Act as allergens or irritants • No known effect on human and animal health trichothecene mycotoxins in grain in • Act on other micro-organisms, such as penicillin’s the USSR late in World War II antibiotic action • Effective in animal feed or food, and sometimes both, • In 1960, in which 100,000 turkeys • Human and animal health has been proven. died of an unknown disease Mehrdad Tajkarimi DVM PhD Mehrdad Tajkarimi DVM PhD VMPHR 250 07 UC Davis VMPHR 250 07 UC Davis Mycotoxin production and Aflatoxin occurrence • Can be produced by three species of Aspergillus — A. flavus , A. parasiticus , and the Can occur: rare A. nomius • I n the field; Aspergillus flavus and • Aflatoxin B1 is a potent liver carcinogen and some Fusarium species DNA-damaging agent • Pre-harvest; some Fusarium species • Aflatoxins are very heat resistant and are and Trichothecium difficult to remove from foods and feeds • Processing ? • Aflatoxins M 1 and M 2 are the hydroxylated • Transportation ? metabolites of aflatoxins B 1 and B 2 and can be • Storage; Penicillium are mainly found found in milk or milk products Mehrdad Tajkarimi DVM PhD Mehrdad Tajkarimi DVM PhD VMPHR 250 07 UC Davis VMPHR 250 07 UC Davis 1

Fumonisins Ochratoxins • Produced primarily by Fusariun • Produced by Aspergillus and Penicillium verticillioides • Occurs primarily in cereal grains and • Most common fungi colonizing corn and mixed feeds, but it can also be found in corn-based foods as well as other grains beans, coffee, fruit juices, nuts, olives, (such as sorghum and rice) throughout cheese, fish, pork, milk powder, pepper, the world wine and beer • Several reports of a possible role in the etiology of human esophageal cancer Mehrdad Tajkarimi DVM PhD Mehrdad Tajkarimi DVM PhD VMPHR 250 07 UC Davis VMPHR 250 07 UC Davis Trichothecenes Deoxynivalenol • Toxic metabolites produced in the genus • Produced primarily by F. graminearum Fusariun • Feed refusal and emesis in swine, named • Affect many organs, such as the “vomitoxin” gastrointestinal tract and the • It is considerably less toxic than most hematopoietic, nervous, immune, other mycotoxins hepatobiliary and cardiovascular systems • Alimentary toxic aleukia (ATA). • T-2 toxin is a highly toxic type A TCTC Mehrdad Tajkarimi DVM PhD Mehrdad Tajkarimi DVM PhD VMPHR 250 07 UC Davis VMPHR 250 07 UC Davis Sterigmatocystin Genus Penicillium • Cyclochlorotine, luteoskyrin, and rugulosin • Produced by fungi in the Aspergillus , are hepatotoxins mycotoxins Bipolaris , and Chaetomium genera and by • patulin , penicillic acid, citrinin, Penicillium luteum cyclopiazonic acid, citreoviridin and • Precursor in the metabolic pathway to xanthomegnin aflatoxin production, but is toxic in its own • Patulin is often found in damaged apples, right, though not as potent as aflatoxin B1 apple juice, apple cider • At least 10 countries have regulatory limits Mehrdad Tajkarimi DVM PhD Mehrdad Tajkarimi DVM PhD VMPHR 250 07 UC Davis VMPHR 250 07 UC Davis 2

Mycotoxin preventive Mycotoxin preventive measures measures Monitoring programs to avoid human Toxin formation : exposure: • Using resistant varieties • Monitoring and measures of mycotoxins in food and animal feed • Good agricultural practice • TLC, HPLC and GC techniques • Drying grain to less than 10–13% • New chemical methods • Capillary electrophoresis • Antifungal agents and phenolic • Fluorescence polarization antioxidants and antibiotics • Immunoassay (simple approach) • Biosensors Mehrdad Tajkarimi DVM PhD Mehrdad Tajkarimi DVM PhD VMPHR 250 07 UC Davis VMPHR 250 07 UC Davis Mycotoxin preventive Mycotoxin preventive measures measures Remove mycotoxins from commodities Cooking and pasteurization • Chemical detoxifiers, including acids, • Do not destroy mycotoxins generally alkalis, aldehydes • Oxidizing agents and gases such as • Extrusion cooking is effective for chlorine, sulfur dioxide, NaNO 2 , ozone, detoxifying DON, and roasting has some ammonia are used for aflatoxins, effect in reducing OA in coffee fumonisin and trichothecene. Mehrdad Tajkarimi DVM PhD Mehrdad Tajkarimi DVM PhD VMPHR 250 07 UC Davis VMPHR 250 07 UC Davis Miscellaneous fungi - Ergot Mushrooms • Convulsive type, convulsions, tingling sensation of • Amanita phalloides (Death Cap) muscles, and sometimes the entire body is racked by • Amanita muscarina spasms • European and most other countries, limit of 0.1–0.2% • Coprinus atramentarius • In the US, wheat or rye with 0.3% sclerotia is • Galerina spp. considered unsafe and oats, triticale, or barley having more than 0.1% • Gyromitra esculenta • Ethiopian epidemic in 1978 from ergot-infested oats. • Psilocybe mexicana Approximately 50% of the affected persons died • Similar problems occurred in India in the 1970's • Quorn™ ?! Mehrdad Tajkarimi DVM PhD Mehrdad Tajkarimi DVM PhD VMPHR 250 07 UC Davis VMPHR 250 07 UC Davis 3

Amanita phalloides Amanita muscarina (Death Cap) • Contains 2–3 mg of amatoxins per gram of dry • Death does not usually occur when these are tissue the only toxins in the poisonous mushrooms • A single mushroom can kill an adult human • Vomiting, nausea, abdominal pain, and bloody • Fly agaric also contains amatoxins and diarrhea that develops within 6–24 hours phallotoxins • These signs may lessen for a short period of 12– 24 hours followed by confusion, delirium, • Fatal combination of symptoms may occur. seizures, and coma • The mortality rate in humans is 10–40% Mehrdad Tajkarimi DVM PhD Mehrdad Tajkarimi DVM PhD VMPHR 250 07 UC Davis VMPHR 250 07 UC Davis Coprinus atramentarius Galerina spp. • Symptoms typically begin about 30 • Small, brownish mushrooms commonly minutes after drinking alcohol growing on wood • These mushroom are easily confused with the edible, two-toned Pholiota • May occur for as long as 5 days after ( Kuehneromyces mutablis ) that also grows mushroom ingestion on wood in clumps Mehrdad Tajkarimi DVM PhD Mehrdad Tajkarimi DVM PhD VMPHR 250 07 UC Davis VMPHR 250 07 UC Davis Gyromitra esculenta Psilocybe mexicana • Contains gyromitrin • Mexican mushrooms, magic mushrooms, or shrooms • Causes a bloated feeling, nausea, vomiting, • Symptoms begin about 30–60 minutes after watery or bloody diarrhea, abdominal pain, muscle cramps, faintness, and loss of motor ingestion coordination • include pleasant or apprehensive mood, • Typically occur 6–12 hours after eating the unmotivated laughter and hilarity, compulsive mushrooms movements, muscle weakness, drowsiness, hallucinations, and finally sleep • Illness can progress to convulsions, coma, and • Death in small children death Mehrdad Tajkarimi DVM PhD Mehrdad Tajkarimi DVM PhD VMPHR 250 07 UC Davis VMPHR 250 07 UC Davis 4

Quorn™ Quorn™ • Center for Science in the Public Interest (CSPI): • Mycoprotein is derived from Fusarium hundreds of people are becoming violently ill venenatum with problems such as vomiting and diarrhea from eating Quorn • Quorn™ foods have been available in • The company has acknowledged that some Europe for over 17 years people do not tolerate the product well (one in 146,000) • Quorn™ foods have been eaten by 20 • The FDA says it has contacted many of the million consumers, in nearly one billion people who have reported falling ill from servings Quorn™ products, no evidence of it being a serious threat Mehrdad Tajkarimi DVM PhD Mehrdad Tajkarimi DVM PhD VMPHR 250 07 UC Davis VMPHR 250 07 UC Davis Summary Summary • Many fungi that grow on plants in the field and • Several species of mushrooms also contain on feedstuffs and foodstuffs after harvest toxins that can cause serious illness and produce toxins that threaten animal and human death if eaten. health. • A new meat substitute made of fungal • Mycotoxins in animal feeds may eventually protein has attracted the attention of a threaten humans via foods of animal origin. consumer-advocate organization, which • Once present in feeds or foods, mycotoxins are wants it banned. very difficult to eliminate. Mehrdad Tajkarimi DVM PhD Mehrdad Tajkarimi DVM PhD VMPHR 250 07 UC Davis VMPHR 250 07 UC Davis 5