Fjölrit RALA - 22.03.1979, Blaðsíða 50

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color. Ascorbic acid salts are used considerably to promote
the formation of the red color. In addition, nitrite inhib-
its the growth of a dangerous food poisoning bacterium, Clos-
tridium botulinum, in the meat. The poison formed by this
bacterium is destroyed by boiling but this is not sufficient
if the product is eaten raw or parboiled, such as ham, sand-
wich meat and certain types of sausages.
B. What effects do nitrates and nitrites have on the
human body ?
Nitrate salts (KNOg and NH^NO^) have been used for
many years to achieve relief from edema. No toxic effects
are known to have resulted from such treatment, and it has
therefore been concluded that nitrates in small amounts
are themselves not "toxic.
Nitrite is much more questionable than nitrate but it
has been used to achieve dilation of smooth muscle and there-
fore vasodilation and lowering of blood pressure. Doses of
30-300 mg of NaNO^ have been given therapeutically for vaso-
dilation. If the dose is increased up to one gram, for ex-
ample, the compound becomes lethal.
Nitrite can bind to hemoglobin causing methemoglobinemia.
As a result, hemoglobin loses its ability to transport oxygen
which may lead to asphyxia and suffocation.
These symptons are most common in infants, the reason
being that the acidity of infants' stomachs is not high
enough to prevent the growth of bacteria which may convert
nitrate to nitrite. Nitrate poisoning in infants has some-
times occurred after consumption of nitrate-rich drinking
water or vegetables. The lethal dose is 90 mg of nitrate
per kg of food. The legal limit of nitrate in drinking water
in the U.S.A. is 46 mg per kg (liter). Older individuals may
also acquire these symptons if they consume meat containing
high levels of nitrate and nitrite.
When nitrite reacts with amines or amides in the food,
so-called nitroso-compounds are formed. This reaction can
occur in the food itself or in the digestive tract after
consumption of the food. It can occur in individuals with
high gastric acid levels. It is more common in people with