Nitrosamines and margarine.

Nitrosamines and margarine

There have been reports in recent years that certain margarines were contaminated with trace levels of n-nitrosomorpholine (NMOR), a volatile nitrosamine that the National Toxicology Program classifies as a potential human carcinogen. But it was unclear whether the chemical was introduced by the testing procedures themselves, or by some commercial production technique. Now a Canadian study not only confirms the presence of NMOR in several margarines but also identifies its source--their paper wrappers.

Many of these wrappers contain between 5 and 73 nanograms of NMOR, the study shows. Though samples from the inner core of a stick of margarine showed no NMOR, the outer 1 centimeter could be contaminated with as much as 14 parts per billion NMOR, according to a report in the January-February JOURNAL OF FOOD SCIENCE by Nrisinha Sen and Philamder Baddoo of Health and Welfare Canada's health-protection branch in Ottawa.

Not all paper-wrapped margarines were contaminated. In fact, they point out, margarines in the most highly contaminated wrappers were never contaminated, because, coincidentally, a shiny plastic coating had been sprayed onto the inner surface of the waxed paper used in these cases, preventing the contaminant from reaching the margarine.