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Sue
Moderator
Geregistreerd op: 13-1-2005
Berichten: 48764
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| Natuurlijke gifstoffen in etenswaren |
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Ik werd op dit artikeltjes gewezen door iemand op het Engelstalige forum:
nzfsa.govt.nz/consumers/food-safety-topics/chemicals-in-food/natural-toxins |
Zondag 29 Mei 2005 8:46 am |
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ettie_
Eitje
Geregistreerd op: 26-5-2005
Berichten: 17
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De link kan wegens je kopieer beveiliging niet worden gekopieerd in de adresbalk in explorer en ook is het geen link. Je moet hem dus letterlijk over tikken en ik ben bang dat de meesten dat niet zullen gaan doen...
Mss is er nog een andere oplossing? |
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Maandag 30 Mei 2005 9:23 am |
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Sue
Moderator
Geregistreerd op: 13-1-2005
Berichten: 48764
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| Re: Natuurlijke gifstoffen in etenswaren |
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Food contains natural chemicals that are essential for growth and health, including carbohydrates, sugars and proteins and vitamins. But some foods contain potentially harmful poisons called natural toxins.
The reason for the presence of natural toxins is not always known. In some foods, a toxin is present as a naturally occurring pesticide to ward off insect attack. Or it may be formed to protect the plant from spoilage when damaged by weather, handling, UV light or microbes.
Commonly eaten foods that may contain natural toxins include:
Fruit seeds and pits
Apple and pear seeds and the inner stony pit of apricots and peaches contain a naturally occurring substance, amygdalin, that can turn into hydrogen cyanide in the stomach causing discomfort and illness and in some cases can be fatal.
Accidental swallowing of an occasional seed or pip is not a concern but cases of human poisoning after eating apple seeds and apricot pits have been reported. Don’t make a habit of eating the seeds from these fruits. For a young child, swallowing only a few seeds or pits may cause illness and in rare cases can be fatal.
Kumara, a member of the sweet potato family, can produce toxins in response to injury, insect attack and other stress. The most common toxin, ipomeamarone, can make the kumara taste bitter. There have been reports of cattle deaths after they have eaten mouldy kumara. The toxin levels are usually highest near the area of damage. It is recommended that any damaged parts on kumara are removed before cooking, and do not eat it if it tastes bitter after cooking.
Parsnips commonly contain a group of natural toxins known as furocoumarins. These are probably produced as a way of protecting the plant when it has been stressed. The concentration of the toxin is usually highest in the peel or surface layer of the plant or around any damaged areas.
One of the toxins can cause stomach ache and may also cause a painful skin reaction when contact with the parsnip plant is combined with UV rays from sunlight.
It is important to peel the parsnip before cooking and remove any damaged parts. The levels of toxin drop when the parsnip is cooked by baking, microwaving or boiling. Discard any cooking water.
All potatoes contain natural toxins called glycoalkaloids. The levels are usually low but higher levels are found in sprouts, and the peel of potatoes that taste bitter. The toxins are produced by the plant in response to stress such as microorganisms, UV light, and damage such as bruising. The amount of toxin depends on the type of potato and the growing conditions.
Severe stomach ache and even death from glycoalkaloid poisoning has been reported overseas, but is very unusual. Glycoalkaloids are not destroyed by cooking, so it is important to avoid eating the sprouts and to remove any green or damaged parts before cooking. Do not eat cooked potatoes that still taste bitter. If you come across a green potato crisp, it’s probably best not to eat it. Remember to store potatoes in a dark, cool and dry place.
Many types of beans contain toxins called lectins. The highest concentrations are found in kidney beans, especially red kidney beans. As few as four or five raw beans can cause severe stomach ache, vomiting and diarrhoea.
To destroy the toxins, soak the beans for at least five hours and then boil briskly in fresh water for at least 10 minutes. Do not cook beans at a low temperature, for example in a crock pot, as it may not destroy the toxin and improperly cooked beans can be more toxic than raw ones. Tinned beans can be used without further cooking.
Rhubarb contains naturally occurring oxalic acid. The amount depends on the age of the plant, the season, the climate and the type of soil. Highest concentrations are in the leaves and these should not be eaten.
Oxalic acid poisoning can cause muscle twitching, cramps, decreased breathing and heart action, vomiting, pain, headache, convulsions and coma.
Zucchini may occasionally contain a family of natural toxins called cucurbitacins. These toxins give zucchini a bitter taste. Bitterness in wild zucchinis has been known for a long time but is rarely found in commercially grown zucchinis.
Bitter zucchinis have caused people to experience vomiting, stomach cramps, diarrhoea and collapse. Do not eat zucchini that have a strong unpleasant smell or taste bitter.
Cassava and Bamboo Shoots
FSANZ has recently issued advice on the preparation of cassave and bamboo shoots because of the presence of a naturally occurring toxin called cyanogenic glycosides in raw or unprocessed cassava and bamboo shoots. This can lead to exposure to hydrogen cyanide and its related toxicity.
Cassava is also known as yucca, tapioca (a processed product of cassava), gaplek or manioc. Bamboo shoots, a traditional componant of Asian cuisine, are sourced from the underground stems of the bamboo plant.
To avoid exposure to this toxin, sweet cassava should be prepared before eating by first peeling and slicing the cassava and then cooking it thoroughly either by baking, boiling or roasting. Frozen cassava, and frozen peeled cassava should also be prepared in this way.
Fresh bamboo shoots should be sliced in half lengthwise, the outer leaves peeled away and any fibrous tissue at the base trimmed. It should then be thinly sliced into strips and boiled in lightly salted waterfor eight to ten minutes.
Consumer’s individual sensitivity to a natural toxin, as well as the concentration (strength) of the toxin present, will determine whether or not it will cause an adverse reaction as well as the strength of symptoms experienced.
Consumers can limit their exposure to natural toxins by following the simple practices outlined above.
It is important to include a wide variety of fresh fruit and vegetables in your diet as these foods lower the risk of more serious health problems (such as heart disease, cancer, diabetes and obesity) than those associated with natural plant toxins.
Remember the Ministry of Health recommends 5+ servings of fruit and vegetables per day. |
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Maandag 30 Mei 2005 9:28 am |
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Tijden zijn in GMT + 1 uur. Het is nu Maandag 28 Mei 2012 2:30 pm
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