Joint International Conference on Long-term Experiments ...

turn, react to produce larger concentrations of N-nitrosamines upon frying. Samples 3, 6, 17,
and 21 in Table 2 were held at 72°F 34 hr above
that of Samples 2 and 16, while Samples 6 and 21 showed little or no increase. A reason for
these apparent inconsistencies could be the amount of residual nitrite present in the bacon.
Producers use different concentrations of nitrite in their cures. Bacon with a low residual
nitrite does not show an increase in nitrosamine formation after storage at room temperature,
since there is an insufficient quantity of nitrite available to react with the additional amines
formed. On the other hand, bacon with a high residual nitrite, which can continue to react
with the amines as they form at room temperature, may show a greater formation of
nitrosamines. After frying, the bacon was found to contain increased levels of Nnitrosopyrrolidine.
Table 3 shows the results of N-nitrosamine analyses on a variety of food products. Two
types of baby foods that contained meat cured with nitrite were analyzed, but no
nitrosamines were found (Samples 27 and 28). Of the 5 variety meat samples analyzed
(Samples 29-34), only the fried canned bacon (Sample 32) showed N-nitrosopyrrolidine to
be present. A peak at the retention time of N-nitrosodimethylamine (DMNA) was also
observed but the concentration was too low to confirm its identity.
Six total diet samples were analyzed (Samples 35-40) comprising (1) grain and cereal
products; (2) meat, fish, and poultry; (3) leafy vegetables; (4) root vegetables; (5) oils, fats,
and shortenings; and (6) dairy products. (These composites represent the typical diet of an
American male teenager between 15 and 19 years of age.) Because of the physical nature of
the oils, fats, and shortenings sample (Sample 40) and the dairy products sample (Sample
35), they were analyzed by the procedure for fat cooked out of bacon. None of the 6 total
diet samples analyzed was found to contain N-nitrosamines.
Since lard is produced from rendered pork fat (in some instances a cured product) and
high levels of N-nitrosopyrrolidine have been found in fried bacon and fat cooked out of
bacon, it was decided to analyze a sample of lard (Samples 41 and 42). No N-nitrosamines
were found, even after heating at 340°F for 10 min.
Several workers have reported finding DMNA and N-nitrosodiethylamine in cheese,
which had been processed with nitrite. However, none of the data had been confirmed. In
order to verify these findings we surveyed 10 imported cheeses (Samples 43-52). None of
the 14 volatile N-nitrosamines was found in any of these products.
Lamb is prepared by soaking it in a similar salt solution and further treated by smoking
for 6-8 hr over sheep manure. The high concentration of amines normally found in fish
coupled with the added nitrite and unusual mode of food processing should have provided
an ideal environment for nitrosamine formation. As shown in Table 3, 18 different samples
were analyzed (Samples 53-70). Despite the apparently ideal environment, no nitrosamines
were found in any of the samples.
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