(1) One meaning of denature in food science is to render a foodstuff unsuitable for consumption because it does not comply with food laws or regulations. An example in fish technology would be where a public health inspector or veterinarian had considered fish unfit for human consumption, or where fish had been withdrawn from the market as a consequence of the EC marketing regulations. (2) In protein chemistry, denaturation is the phenomenon of an alteration in the tertiary structure of a protein. Covalent bonds such as disulphide bonds might be broken during denaturation, but there is no breaking the polypeptide chain of the molecule.