some other bacteria, produce the lethal tetrodotoxin , which is present in the tissues of some living animal species rather than being a product of decomposition . http://en.wikipedia.org/wiki/Foodborne_illness PubMed - The influence of bacterial exotoxins on the activity of the thyroid gland in different species http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1356738/?page=1  Treatment of Diseases Caused by