Evaluation of the histamine content and potential toxicity of some of the consumable food

Consuming large amounts of histamine with food causes histamine poisoning in consumers. Little information about the content of histamine in food is available in the country. In the present study, the histamine content of some samples of food usually consumed in the human diet and which may contain histamine based on the literature, were measured.
The study was performed on 240 samples from 16 different types of food commonly used in the human diet. Histamine was extracted with 75 % ethanol- 0.4 N HCl in fresh and canned fish samples and with 0.1 N HCl in other samples. After passing the extracts through ion exchange chromatography column, the fluorescence derivative of histamine was generated by O-phthaldialdehyde and the amount of fluorescent light was measured at excitation wavelength of 350 nm and emission wavelength of 444 nm.
Spinach, fresh fish, canned fish and eggplant samples showed the highest histamine level with the mean levels of 5.04, 3.83, 2.77 and 2.64 mg/100g. All the tested samples of spinach, fresh fish, canned fish and eggplant contained histamine and 53.3, 20.0, 13.3 and 13.3 % of these samples contained more than 5.0 mg/100g histamine, respectively. Low levels of histamine were found in some samples of tomato, pickled cucumber, walnut, banana, orange, melon, cheese, kashk, yoghurt and doogh; and non-detectable levels of histamine were found in olive and tea samples.
This study confirmed the fact that, fish and seafood products have a high risk of histamine poisoning; and also showed that the risk of histamine poisoning in humans, due to the consumption of spinach and eggplant would not be less than fish and its products. Hence, awareness of the histamine content of the diet food is also important, in the sense that, it could be a warning for contraindication of those food together, especially in people sensitive to histamine poisoning.