Complaint casebook Foreign matter in miso

There was a white powder on the surface of the miso.

Foreign matter (enlarged) in miso

Infrared spectroscopy: We found a spectrum similar to thyrosine.

What looked white like a mold was the crystal of tyrosine. Tyrosine is a type of amino acid contained in miso, which is not particularly harmful to the body.

Thyrosine: A type of amino acid, extremely difficult to soluble in cold water. Because of its small solubility in water, this tyrosine is precipitated by changes in temperature and pH, and the action of bacteria, self-extermination enzymes, etc. It often adheres to boiled bamboo shoots in white powders and is said to be likely to occur if stored for a long time.

Published on March 8, 2007