Roles of Microorganisms in the Deterioration of Rockfish

Abstract

Seven species of microorganisms indigenous to fish were inoculated into sterile fish muscle, obtained from Sebastodes alutus and Sebastalobus alascanus , and the production of total volatile acids (TVA) and total volatile bases (TVB) was determined during storage at 1 C. No production of TVA and TVB was noted in sterile fish, fish inoculated with Pseudomonas type III species (PIII-985), or fish inoculated with Flavobacterium (F-1070). The inactivity of PIII-985 was due to its low maximal growth level, whereas the inactivity of F-1070 was due to its slow growth rate. Pseudomonas type I species (PI-950), Pseudomonas type II species (PII-952), and two Achromobacter ( Acinetobacter ) species (A-981 and A-70) grew and actively produced TVA and TVB. TVB levels increased steadily even after the microbial number reached a maximum, whereas TVA levels declined toward the end of the storage period. It appeared that a minimal microbial growth level of 10 8 cells/g was needed before detectable levels of TVA or TVB could be produced. Regardless of genera, microorganisms which grew well in fish were able to produce TVA and TVB.