Quick Answers
I have a hard, white material like "fish scales" in my homemade ketchup. Is it safe to eat?
These white deposits are calcium nitrate and are
commonly found in home canned pureed or mashed tomato
products. They are considered safe to eat. This occurs
due to the mashing or pureeing process. It is not known
why this occurs, however these deposits seem to vary
with growing seasons and geographic locations of the
harvested tomatoes. The deposit is usually on the
surface or attached to the side or the lid of the jar.
Simply remove with a clean spoon. The texture of calcium
nitrate distinguishes it from mold growth, as it is
hard, like fish scales, and won't disintegrate when
rolled between fingers.
Sources: MSU "Hot Lines," Oct/Nov
1982 "Hot Lines," 82-10,11 Food Features #6, June 1983
Last update: Tuesday, May 05, 2009
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