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mycotoxins

    ochraceus and P.

    Mycotoxines

    Control

    The control and detection of mycotoxins is a continuous process in commodity production.

    The use of immunoaffinity columns for analysis of most of the main mycotoxins has greatly improved analysis in terms of quantification, purification and convenience.

    Ochratoxin A

    Ochratoxin A (OTA) is produced by particular Aspergillus and Penicillium species.

    Patulin

    Patulin is produced by different species of Aspergillus and Penicillium Byssochlamys and Paecilomyces can also be involved. expansum is the most well known for causing a blue rot of apples and is associated with patulin production in apple products.

     Corn which is contaminated with A.

    a wider range of fruits and vegetables The toxin is associated with P.

    This approach should be considered as a method for reducing patulin in other commodities.

    :by vomiting, abdominal pains,pulmonary oedema, convulsions, coma, and (rarely) death. flavus and subjected to increased moisture by 18 % for 4-6 h can increase aflatoxin levels

    Early harvesting of corn followed by drying may avoid increased aflatoxin contamination Grain needs to be dried to 15% or less before storing and toxin production.

    T-2 toxinwas probably the cause of “alimentary toxic aleukia” which affected thousands of people in Siberia during the Second World War.

    Fumonisins, trichothecenes, and zearalenone

    Fumonisins, trichothecenes, and zearalenone are the most important mycotoxins produced by Fusarium, a producer of a wide range of toxic compounds.

    Notable outbreaks were the death of 3 people in Taiwan in 1967 and 100 people in India in 1974, from aflatoxin in rice and corn respectively.

     These parameters, if not kept at the desired levels, may lead to the growth of fungi and the accumulation of mycotoxins in stored crops

    Harvested grain, coffee beans, fruits, and oilseeds crops should be dried immediately.

    It is responsible for haemorrhagic disease in animals and is associated with the formation of oral lesions and neurotoxic effects in poultry. verrucosum is more prevalent in regions with temperate, and A., UK, Denmark, Sweden and in the Balkans (former Yugoslavia) and (b) India ., propionic acid, mixtures of propionic and acetic acid, or ozon.

     Long-term exposure can:

    increase cancer risk

    suppress the immune system. parasiticus are the main producers of aflatoxins.

     Patulin producing fungi are isolated frequently from vegetables and so products are likely to be contaminated in some cases, and similarly for silage and malt. are note worthy as they may produce heat resistant spores which survive food processing with the potential to produce patulin in processed foods.

    Mycotoxins

    “Mycotoxins are fungal metabolites which, when ingested, inhaled or absorbed

    They are poisonous substances, which occur naturally and are perhaps the most prevalent source of food related health risk in field crops.

    The most significant effect of this and other trichothecenes is the immunosuppressive activity, which is probably linked to the inhibitory effect on the biosynthesis of macromolecules (e.

    These procedures are reported to remove more than 90% of aflatoxins

    Aflatoxins and OTA are rather stable when exposed to dry heat and less stable when exposed to humid heat

    Boiling rice at normal pressure reduces aflatoxins up to 50 %.

    Anywhere that fruit products such as juice are manufactured will have a potential problem.e.

    After harvest, (aw) and temperature.

    These contaminated kernels have a lower density, as does contaminated corn, and thus removal is possible by flotation and density sorting.

    The numerical designation is for the different mobility (Rf value) of the compounds.

    The final safe moisture depends on crop and climatic conditions where stored. carbonarius, A.

    Aflatoxins B1 and B2 are produced by both species but only A. verrucosum.

     Patulin is also degraded by (a) sulphur dioxide,and (b) sulphur containing proteins.

    Fumonisins, trichothecenes, and zearalenone

    Another important Fusarium toxin is zearalenone (ZEA), which has oestrogenic properties.4 billion

    Mycotoxins:The field of mycotoxins is complex and interdisciplinary.

    Others are cleaning, insect control, use of antifungal agents and maintaining integrity of the seed coat.

    Enzymes and microorganisms are used frequently in food processing and may transform mycotoxins into other compounds with less or unknown toxicity This is the case with proteases.

    However, the more important mycotoxins belong to species of Aspergillus,Fusarium, and Penicillium. Byssochlamys spp. However, the latter are more common and therefore more relevant to food safety. parasiticus is able to produce detectable amounts of G1 and G2.

    Consumption of food with high levels can be fatal.

    Immunological test kits such as ELISA are available but they are not as accurate as the chromatography-based methods.

     Unfortunately, they are also considered as potential weapons and so could enter the food chain by this route.

    The penicillia are probably the more important producers on grains

     In other commodities, the most common are A.

    Tricothecenes are related compounds and the more important are grouped into type A or type B., DNA, proteins).

    Aflatoxins were the first mycotoxins to have their content regulated in foodstuff.g.

    TLC is optimal for the detection of previously unknown “new” compounds because of the more universal detection methods employed

    Control: Good agricultural practice (GAP)

    In the case of peanuts, it is known that the formation of aflatoxins in the plant takes place when ambient temperatures of 25 to 32 °C occur simultaneously with low humidity in the soil.g. A third species, A. It involves 5 interrelated
    systems

    Mycotoxins and Relevant Fungi

    Filamentous fungi, taken as a whole, produce thousands of toxic compounds.

    In fact, in all countries where regulation exists for mycotoxins, there are tolerances concentrations for aflatoxins in foods or animal feedstuffs .

    They can hydrolyze thepeptide bond of OTA yielding phenylalanine and the much less toxic ochratoxin alpha.

     P.

     OTA has been associated with Balkan endemic nephropathy, which is potentially fatal.

    Aflatoxins present in edible oil after its extraction from seeds are mainly dispersed

    Water is a good solvent for OTA in certain food matrixes, such as coffee:so brewing coffee is the perfect way of extracting OTA from the coffee grains to the cup!

    aflatoxin M1 usually has a higher concentration in cheese than in milk

    However, aflatoxins are generally insoluble in water and so may also dissolve more readily in the lipid rich cheese fraction.

    Aspergillus flavus was discovered in the feeds and was named aflatoxin after the fungus.

     Mycotoxins have plagued mankind before and since the beginning of organized crop production.

    The impact of mycotoxins on human and animal health is now recognized and it is estimated that they cause high economic losses. cerevisiae transforms patulin into other compounds during alcohol production in cider production. Initially, thin layer chromatographic(TLC) methods were employed

    However, this has been superseded, in many cases, by high performance liquid chromatography (HPLC). ochraceus and P.

    :They attract worldwide scientific, political and economic attention because of the significant economic losses associated with impacts on human health, animal productivity and international trade.

    Therefore, it is possible to control

    the biosynthesis of aflatoxins in peanuts by controlled irrigation at critical periods of the day. ochraceus with tropical climates.

     B and G refer to the blue and green colours observed after thin layer chromatography (TLC). Increasing the temperature increases the level of aflatoxin transformation: a pressure-cooking can degrade aflatoxins by 70 %.

     P.

     

    .

    Aflatoxin M1 (M for milk) is a very important toxin in milk and products and is a minor metabolic product of these Aspergillus species.

    Degradation of OTA to a maximum of 90 % is possible, depending to the conditions of operation while roasting (e. temperature usually between 200 and 250 °C and resident time from 5 to 20 minutes).

    by the consumption of rye contaminated with ergot alkaloids, a known mycotoxin of Claviceps purpurea .

     OTA is partially removed from coffee beans during roasting. carbonarius is associated with grape products

    OTA is found in corn, wheat, sorghum, oats, rice, and green coffee.

    Removal during processing

    Frying can reduce aflatoxins by 60 % when oil temperature is at 150 °C for 20 minutes.g.

    since the1960’s,Over 100 000 turkeys and a large number of ducks and pheasants died.

    For example, the annual cost in the US alone was estimated as US$1.

    However, it apparently occurs mainly in dairy products as a transformation product by cows of the aflatoxin B1 contained in animal feeds. Gas chromatography is often used for Fusarium mycotoxins.

    Type A are more toxic than type B.

    Removal of mycotoxins after harvesting

    Damaged kernels may exhibit differences in colour, density, shape or size. verrucosum are associated with cereal products, and are the primary producers of OTA.

    Highest levels have been detected in barley, oats, wheat and corn in (a) Northern Europe, i.

    corn, grapes, dried fruits and wheat is generally below 500 μg kg−1.

    Ochratoxin A

    A.

    from granulated products, such as cereals, bean or others, since contaminated kernels have distinctive characteristics.

    It occurs frequently in the USA where the FDA operates mandatory action levels in apple juice.

     production, storage, transportation and processing chain

    Analysis is normally by chromatography.

    aflatoxins, ochratoxin A (OTA), patulin,deoxynivalenol (DON), fumonisins, nivalenol (NIV), T2-toxin, and zearalenone (ZEA)

    Aflatoxins

    Aspergillus flavus and A. expansum blue rot of apples and grapes.

    S.

     Insects and rodents need to be controlled as they create conditions suitable for fungal growth,

    Air treatment in storage facilities may prevent growth and contamination, e
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