Studies on Nitrosamines in Foods (VIII)

Nitrosamines Detected in Foods

Abstract

There have been many reports on the presence of nitrosamines in foods, but the methods of extraction and identification have not always been adequate and some of the results have been conflicting. The authors tried to detect nitrosamines in 149 samples of Japanese commercial food, and dimethylnitrosamine (DMNA) and diethylnitrosamine (DENA) could be identified in 15 samples.
Extraction was carried out by modified procedure of Howard method and identified by thin-layer chromatography. Recovery of extraction of DMNA from foods by the above modified method was 50-60% and the detection limit on TLC plate was 0.2μg of DMNA with ninhydrin.
DMNA was detected in 6 among 20 samples of the pressed ham, which materials were pork, whale and (or) tuna meat, and also detected in 1 sample among 3 samples of hamburger consisted of pork and whale meat. Although DMNA and DENA were detected in 7 among 20 samples of salted salmon roe in which sodium nitrite was used as a color fixative, these contents were trace. The amounts of DMNA in the pressed ham could not be exactly determined by TLC method, but from the detection limit on the plate the contents were presumed to approximately as 15-25ppb.
In salted cod roe purchased in markets, no nitrosamines were detected, but nitrite-treated cod roes which were processed in our laboratory showed over 1 ppm of DMNA and DENA contents. This fact indicates that the addition of nitrite to secondary amine-rich foods, such as fishes, fish roes or whale meat may be possible hazard to human health.