en Fish processing Fish processing پژوهشي Orginal research papers Mahyaveh is an Iranian fermented fish sauce produced from fish, salt, spices and water during fermentation period. The main problem related to this product is very high histamine content of it. Effects of starter cultures (<em>Lactobacillus plantarum</em> and <em>Paenibacillus</em><em> polymyxa</em>) on reduction of histamine in mahyaveh, as &ldquo;Southern Iran Fermented Fish Sauce&rdquo; were investigated. This study was performed in 4 experimental groups, including control and treatments on 30^th and 45^th days of the product. Chemical analysis of treated and control samples revealed that pH, salt percentage, TVB-N content decreased significantly (<em>p</em><0.05), and acidity increased significantly (<em>p</em><0.05) in treated samples compared to control samples. Also inoculate starter culture (<em>Lactobacillus plantarum</em> and <em>Paenibacillus</em><em> polymyxa</em>) reduced the amount of histamine content to about 0.347 and 0.326 mg mL^-1 from 0.473 and 0.368 mg mL^-1 in control and treated samples, respectively. Results of microbial evaluation revealed that populations of<em> Halophiles, Enterobacteriaceae </em>and fungi decreased significantly in treated samples compared to those of control samples (<em>p</em><0.05), but colony populations of <em>Bacillus </em>and LAB increased significantly in treated samples compared to those of control samples (<em>p</em><0.05). In general, addition of starter culture had a positive effect in reducing the amount of histamine and improving other chemical properties and microbial quality of the fermented fish sauce. Fish sauce, Histamine, Lactobacillus plantarum, Mahyaveh, Paenibacillus polymyxa 663 677 http://jifro.ir/browse.php?a_code=A-10-3175-2&slc_lang=en&sid=1 M. Nazari m.nazari720710@gmail.com 100319475328460040301 100319475328460040301 No North Tehran Branch, Islamic Azad University, Tehran, Iran N. Mooraki nargess_mooraki@yahoo.com 100319475328460040302 100319475328460040302 No North Tehran Branch, Islamic Azad University, Tehran, Iran M. Sedaghati marjanehsedaghati@yahoo.com 100319475328460040303 100319475328460040303 Yes North Tehran Branch, Islamic Azad University, Tehran, Iran