3 mycotoxins Flashcards
what is the origin of the word mycotoxin?
-greek word: ‘mykes’ meaning ‘fungus’
-latin word: ‘toxicum’ meaning ‘poison’
what are mycotoxins?
-chemicals produced but fungi that have toxic effects on animals and humans
-the chemical structure of mycotoxins is very diverse
what is the diversity of mycotoxins?
-300-400 mycotoxins presently identified, with more becoming evident as new isolation techniques are used
-chemical structure and toxic properties of mycotoxins are conserved during both storage and processing/cooking of food and feed
-THEY ARE VERY DIFFICULT TO REMOVE
what are the products that are effected by mycotoxins?
-mycotoxins occur in many varieties of food and feed
-food crops most often affected are corn, peanuts, cottonseed, sorghum, wheat, barley, coffee, cocoa and tree nuts
-also been found in rice, beer and wine
-in canada, mycotoxins occur mainly in cereal grains and corn but have been reported in other crops such as alfalfa and oilseed
what is the long history of mycotoxins?
-mycotoxin contamination has affected humans and animals for thousands of years
-in 7th and 8th century, festival for Roman God Robigus, protector of grain and trees was celebrated to starve off rust and mold
-middle ages had outbreaks of ergotism (look like black rice, same fungus as LSD)
-only in the last 30-40 years have scientists been able to isolate specific toxins from their fungal source
what did ergotism do to people back in the day?
“a great plague of swollen blisters consumed the people by a loathsome rot, so that their limbs were loosened and fell off before death
what causes production of mycotoxins?
the optimum conditions for toxin production are relatively specific for each fungus
-climate factors
-environmental factors
-crop and livestock grower practices
what are the climate factors that cause production of mycotoxins?
-warmer temperatures favor certain fungi
-drought, rainfall
what are the environmental factors that cause production of mycotoxins?
-insect pests
-suitability of hybrid for region
what are the crop and livestock grower practices that cause production of mycotoxins?
-harvesting when wet, rather than allowing crop to ‘dry down’
-insufficient dying
-wet, warm, pest-ridden storage conditions
-long periods of animal feed storage
when are mycotoxins produced?
mold contamination usually occurs in the field. mycotoxins can develop at various stages:
-pre-harvest growth
-harvest
-storage
where are mycotoxins found?
what are mycotoxins in food and feed supply?
-estimated that 25% of world’s crops are contaminated with mycotoxins. Chronic exposure occurs in populations of some developing countries
-mycotoxins are a current, continuing, chronic problem for world food and feed producers
why are mycotoxins important?
mycotoxins are important because they can be costly when they affect:
1. animal productivity
2. human health
3. international trade
-the food and agriculture organization of the united nations (FAO) states the cost of mycotoxins in canada and united states is approximately $5 billion per year
where do these money losses come from?
-crop yield due to diseases from fungi that produce mycotoxins
-reduced crop value resulting from mycotoxin contamination
-losses in animal productivity from eating mycotoxin-contaminated feed
-human health costs
-additional costs include the cost of management at all levels: prevention, sampling, mitigation, litigation and research costs
what are costs to the agriculture sector?
-losses in performance
-increased health costs
-potential condemnation of feed or animal products
what is aflatoxin?
-one of the most potent known carcinogens
-maize, cotton seed and groundnuts
-major target organs= liver and kidney
-rapid excretion (96 hours)
-can accumulate in tissues (milk)
what are the effects of aflatoxins?
-liver cancer is a serious consequence of long-term exposure of aflatoxins
-other effects: failure to grow, reduced protein synthesis, immunosuppression
-aflatoxins M1, M2 are hydroxylated metabolites of B1 and B2 that are excreted in the milk of lactating animals such as dairy cows
what are the target organs of deoxynivalenol?
intestine, immune system and brain
what are ergot alkaloids?
-earliest recognized mycotoxicosis
-humans consumed bread baked with grain containing ergot spores: LSD symptoms and hallucinations
-grains are replaced by ergot sclerotia that contain toxins
what are the other factors that can influence the toxicity of mycotoxins in animals?
how do we try to mitigate mycotoxins?
- prevention (in the field)
- detection (in the harvested material)
- legislation (in the import/export)
- detoxification (in the feed/food ingredients)
- chemoprotection/prevention (in the animal)
