Fjölrit RALA - 22.03.1979, Page 51

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low levels of gastric acid. In such instances, the acidity
is not sufficient to inhibit the growth of microorganisms
which not only convert nitrate to nitrite but probably also
nitrite to nitrosamines in the stomach.
In other countries, nitrosamines have been found in
foods, especially in cured meat products, but they have
also occurred in cheese, fish, spice mixtures and ciga-
rette smoke. Experiments with animals have shown that
nitrosamines and nitrosamides are carcinogenic. Some
are, in addition, mutagenic and/or teratogenic. All
nitrosamides tested cause tumor formation. Nitrosamides
are readily converted to compounds which damage all cells
they come in contact with and so cancer is formed on the
site of injection. Nitrosamines are more stable and are
only converted to carcinogenic substances in those organs
containing the proper enzyme system. Nitroso-compounds
cause cancer in most of the rat's organs, for example,
the liver, kidneys, lungs, stomach, esophagus, urinary
bladder; nose, intestine, tongue.
Research is now being carried out to investigate the
correlation between nitrosamine distribution and the fre-
quency of gastric cancer. This research may be of great
importance in Iceland because gastric cancer is more common
in Iceland than in most neighboring countries, although the
frequency is lowering. The frequency differs in different
countries indicating that environmental factors play an
important role. As a possible cause, several foods have
been named, either directly or as a source of precursors
of the carcinogenic compounds. It is important to remem-
ber that ascorbic acid salts diminish considerably the
danger of formation of nitroso compounds in the food and
in the body. They therefore benefit both the manufacturer
and consumer.
C. Regulations concerning the use of nitrates and nitrites
According to an Icelandic regulation from 1974, the
legal limit of nitrite (calculated as sodium nitrite - NaNO^)
is 100 mg per kg (100 ppm) and that of nitrate (calculated as
potassium nitrate - saltpeter - KNO^) is 500 mg per kg of
meat (500 ppm). It is forbidden to use nitrate and nitrite
in the same product.