Elevated temperature and time abuse of harvested fish accelerate the growth of microorganisms normally present in the fish, increasing the breakdown of histidine to histamine. Human scombroid poisoning is caused by consuming fish with high levels of histamine. Scombroid poisoning has resulted in human mortality. Histamine production is common in fish such as tuna, mahi-mahi, bluefish, mackerel, anchovies, and sardines. Also, it is produced in menhaden, a fish commonly used in the production of fish meal which is a major protein supplement in animal feeds.
Histamine is extracted from a sample in a quick water extraction process.
This extract is filtered and then diluted into a buffer solution supplied with the test. The buffered sample is then mixed with enzyme-labeled histamine conjugate. The mixed solution is then transferred to an antibody coated well, where the sample histamine competes with the histamine conjugate for antibody binding. Substances that are not antibody bound are removed in a washing step. Enzyme substrate is added, which turns blue due to the action of bound conjugate.