Inhibitory effects of high hydrostatic pressure processing on psychrotolerant biogenic amine producing bacteria and biogenic amine formation in marinated fish

The aim of this study was to investigate the inhibitory effects of high hydrostatic pressure (HHP) processing on psychrotolerant biogenic amine producing bacteria and biogenic amine formation in marinated herring (Clupea harengus). For this purpose, marinated herring fillets prepared with different acid concentrations (2% and 4%) were inoculated with Morganella psychrotolerans and Photobacterium phosphoreum, then treated with HHP (100 MPa, 300 MPa, 500 MPa 5-10 min.) and packed under vacuum. Samples treated with HHP were stored at 4oC for 3 months in order to evaluate the alterations in quality parameters. It was observed that 300 MPa 10 min and 500 MPa HHP processing had significant effects (P<0.05) in suppression of M. psychrotolerans growth in marinated herring prepared with 4% acid. HHP processing over 300 MPa was significantly effective (P<0.05) to inactivate P. phosphoreum (in 4% acid concentration) and no bacteria growth was observed during the storage period. Application of HHP over 500 MPa was efficient in preventing the growth of lactic acid bacteria (LAB) and total psychrophilic bacteria in marinated herring (4% acid) inoculated with M. psychrotolerans. 300 MPa and higher HHP was effective to inhibit LAB and total psychrophilic bacteria growth in 4% acid groups inoculated with P. phosphoreum, while 500 MPa HHP was effective in 2% acid groups inoculated with P. phosphoreum. Hydrogene sulphide (H2S) producing bacteria and yeast-mold growth were observed in only 2% acid groups inoculated with M. psychrotolerans, whereas there was no growth of H2S producing bacteria and yeast-mold in groups inoculated with P. phosphoreum. HHP processing significantly (P<0.05) affected the formation of biogenic amines in marinated herring. Histamine formation was prevented with 500 MPa 10 min HHP treatment in 2% acidic marinade inoculated with M. psychrotolerans, while no histamine formation was observed in 4% acidic marinade. During the storage period, v histamin formation was found in 2% acid groups inoculated with P. phosphoreum, however this formation was considered as insignificant at 300 MPa and higher HHP treatment. Histamin was found insignificant in 4% acid groups inoculated with P. phosphoreum throughout the storage period. In M. psychrotolerans inoculation groups HHP treatment was significantly effective for prevention of the formation of putrescine, while observed in both acid concentration groups. Putrescine formation was found insignificant in 2% acid groups inoculated with P. phosphoreum, while this biogenic amine was not observed in 4% acid concentration during the storage period. Kadaverine was not observed in marinades inoculated with P. phosphoreum and M. psychrotolerans inoculation groups with 4% acid. HHP treatment was effective to suppress tyramine formation in high acid concentration groups inoculated with both bacteria culture. TVB-N values were reached to limit values at 15th day of storage in control groups of M. psychrotolerans inoculated marinades. 4% acid groups treated with 500 MPa HHP maintained their ''good quality'' throughout the storage. HHP treatment significantly reduced the TVB-N formation in 4% acid concentration groups inoculated with P. phosphoreum and TVB-N values were significantly lower than those of 2% acid concentration marinades. During the storage period, considerable differences were found between controls and HHP treated groups in M. psychrotolerans inoculated marinades in terms of TMA-N values. 500 MPa HHP treatment was quite efficient to prevent TMA-N formation in low acid concentration, while pressure over 100 MPa was successful in 4% acid groups. Different acid concentrations were significantly (P<0.01) effective to prevent TMA-N formation in P. phosphoreum inoculation groups. While control groups reached higher values in both acid concentrations, pressure over 300 MPa resulted in suppresion of TMA-N formation. pH values remained lower in HHP treatment groups preaperad with 2% acid concentration. However, pH values showed fluctuations in higher acid concentration groups during the storage time. TBA değerleri tüm gruplarda depolama boyunca artış göstermiş ancak basınç uygulanan gruplarda kontrol gruplarına göre daha düşük bulunmuştur. Yüksek hidrostatik basınç uygulanan grupların duyusal genel beğenisi depolama boyunca kontrol gruplarından daha iyi olmuştur. TBARS values showed increasing in all groups during the storage period, however remained lower in pressure treated groups than the control groups. In high pressure treated groups, sensory quality (general acceptance) found better than control groups throughout the storage. In this study, it was observed that HHP processing has significant effect to control growth of M. psychrotolerans and P. phosphoreum and biogenic amine formation in herring marinades. In order to prevent growth of psychrotolerant biogenic amine producing bacteria and formation of biogenic amine in herring marinades, 4% acid concentration and 500 MPa pressure treatment is most effective. The results showed that, HHP treatment can be used in herring marinades for sustain the good quality.