The impact of high-pressure processing on the growth of Photobacterium phosphoreum and biogenic amine formation in marinated herring

The effects of high-pressure processing (HPP) on Photobacterium phosphoreum growth and biogenic amine formation were evaluated in marinated herring (prepared with 2% acetic acid+8% NaCl; or 4% acetic acid+8% NaCl solutions). Marinated fish fillets were inoculated with P. phosphoreum, vaccum packaged and treated with HPP in different pressure levels (100, 300, and 500 MPa) and pressure holding times (5 and 10 min). Control was left as untreated for both marination group. All batches were stored at 4 +/- 1 degrees C up to 3 months. The results showed that combined effect of HPP and 4% acetic acid had much more inhibitory effect on the growth of P. phosphoreum, especially pressure levels 300 and 500 MPa. During the storage period, H2S-producing bacteria growth was not observed in the groups subjected to 500 MPa pressure. Total psychrophilic bacteria did not grow in 500 MPa pressure treated group and 300 MPa 10 min pressure treated group prepared with 2% acetic acid during the storage period. Histamine was detected insignificant levels in the fillets marinated with 4% acetic acid and treated with HPP. Except for the control group tyramine formation was not found in the samples prepared with 4% acetic acid. Similarly, putrescine was not found in the samples prepared with 2% acetic acid and subjected to HPP treatment at the beginning of the storage. Cadaverine levels were found insignificant amount and 300 and 500 MPa pressure treatments suppressed the formation in 4% acetic acid treated groups compared with 2% acetic acid treated groups. The results of this study revealed that HPP in combination with 4% acetic acid had inhibitory effect on P. phosphoreum growth and suppressed the formation of histamine, tyramine, putrescine and cadaverine.