Feasibility study of reducing histamine and heavy metal in Iranian fermented fish sauce by adding Mahdavi wheat bran

Mahyaveh is a traditional fish sauce that is produced in the southern part of Iran and main problem related to this product is the very high histamine content. This study investigated the chemical properties of mahyaveh, in the presence of wheat bran. The effects of Mahdavi wheat bran investigated on the reduction of histamine in mahyaveh, as “Southern Iran Fermented FishSauce”. Fish sauce samples used in this study consisted of control samples and the treated samples containing 10% and 20% of wheat bran. The histamine and heavy metals concentrations in the mahyaveh samples were determined by an enzymatic assay kit and graphite furnace atomic absorption, respectively. The pH and water activity of fish sauce samples decreased during the 45-day fermentation period (2.07% and 8.13%). While the amount of TVB-N experienced a meaningful increase in the presence of wheat bran (4.95%), the protein content significantly decreased (p<0.05) (3.83%). The iron and mercury concentration range of samples (1.3-6.2 mg/kg and 0.2-0.5 mg/kg) were below maximum permissible limits of WHO/FAO (43 mg/kg and 0.6 mg/kg) but cadmium concentration range of samples (0.6-2 mg/kg) and histamine concentration range of samples (832.21-950.40) were above maximum permissible limits of WHO/FAO (0.2 mg/kg) and FDA maximum permissible limits of (50 mg/kg), respectively. The high levels of histamine in mahyaveh samples decreased significantly (p<0.05) by adding wheat bran (13.3%). Moreover, wheat bran had a considerable reductive effect on the concentrations of heavy metals naming iron (Fe), cadmium (Cd), and mercury (Hg) (77.96%- 66.66% and 50%, respectively). Consequently, the major safety problem related to mahyaveh consumption is the very high histamine content and heavy metals contamination