Formation and diffusion mechanism of histamine in the muscle of tuna fish

Abstract

This study investigates the formation and accumulation of histamine in the fresh meat of tuna fish. Under sterilized conditions, histamine was not detected in the muscles of Thunnus obesus ( T. obesus) stored at 20 °C and 25 °C for 72 h (data not shown). And histamine formation and the diffusion mechanism was studied in T. obesus meat inoculated with two histamine-forming bacteria, Morganella morganii NBRC 3168 ( M. morganii NBRC 3168) and Photobacterium phosphoreum NBRC 13896 ( P. phosphoreum NBRC 13896) and stored at 20 °C and 25 °C for 3 days. The histamine level of the inoculated A1 point accumulated at a level above 4000 mg/kg in the T. obesus sample inoculated with M. morganii NBRC 3168 for 48 h. And the most level of the histamine in the remote B point was 2000 mg/kg at the time the sample was inoculated with M. morganii NBRC 3168 and stored at 25 °C. For the P. phosphoreum NBRC 13896 however, the level of histamine at the inoculated point A was 1800 mg/kg for 48 h when it was stored at 25 °C, while the highest level of histamine distant from the inoculum site B point was found to be approximately 1800 mg/kg. In contrast, when stored at 20 °C, histamine level was higher for the sample inoculated with P. phosphoreum NBRC 13896 than with M. morganii NBRC 3168. While histamine was diffused from the inoculation point in the M. morganii NBRC 3168 sample, it was diffused not only from the inoculated point, but also the remote area in the P. phosphoreum NBRC 13896 sample.