[Level of histamine and tyramine in ripening cheeses].

Histamine poisoning is a foodborne chemical intoxication resulting from the ingestion of food products containing high levels of histamine. Historically, histamine poisoning has been attributed to the consumption of fish species belonging to the Scomberesocidae and Scombridae families and other sea fish, but histamine poisoning outbreaks may occur after the consumption of cheese, or other types of fermented foods. Also tyramine has been proved as a cause of adverse reactions, involving headache, hypertensive crisis and interactions with antidepressive drugs, which were observed after consumption of ripening cheeses. The formation of high levels of histamine and tyramine in foods is directly correlated to the level of microorganisms, possessing the enzymes: histidine and tyrozyne decarboxylases, and also with the concentration of histidine and tyrosine free substrate. Proteolysis, which takes place during ripening of cheeses may play role in the release of free histidine and tyrosine. This study reports on the levels of histamine and tyramine in ripening cheeses taken from Polish food market. 43 samples of soft and hard cheeses were investigated. Histamine was measured according to the AOAC fluorometric method. Tyramine was measured after column separation and purification, according to the spectrofluorometric technique with 1-nitroso-2-ortophtalate aldehyde, according to Carou with couple of modifications by authors. Histamine levels ranged from 0 to 157 mg/kg and tyramine levels ranged from 3.8 to 575 mg/kg. The very high levels of histamine and tyramine in many samples of cheeses support the opinion, that sometimes the storage temperature has not been sufficient to stop bacterial multiplication and in consequence enzymatic activity of decarboxylases of native amino acids--precursors of biogenic amines in ripening cheeses.