Roles of Microorganisms in the Deterioration of Rockfish1

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 108 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 I Technical Paper No. 2450, Oregon Agricultural Experiment Station.

Shelf‐life of Sterile Yellow‐eyed Mullet (Aldrichetta forsteri) at 4°C

“…It has long been known that the flesh of healthy live fish is sterile (Liston, 1980). Several workers have isolated sterile flesh for use in various experiments (Ehira, 1976;Herbert, 1970;Lobben and Lee, 1968;Miller et al, 1973). However, only one report has been published where the shelf-life of naturally sterile flesh has been evaluated by sensory assessment.…”

Bacteria Active in the Spoilage of Certain Sea Foods

“…As a result, Castell and his co-workers (Castell & Anderson, 1948;Castell & Greenough, 1957, 1959Castell, Greenough & Jenkin, 1957 ;Castell, Greenough & Dale, 1959) finally had to use cooked minced fish muscle for large scale work and they maintained it gave results comparable to those with sterile raw muscle tissue. Lobben & Lee (1968) obtained sterile fish flesh by washing the whole fish in running water and thoroughly swabbing with 95% ethyl alcohol. After removal of the skin, the sterile flesh was excised under a W lamp.…”

Spoilage Potential of Some Contaminant Bacteria Isolated from Indian Mackerel (Rastrelliger kanagurta)

“…Increase in TVA and TVBN levels in mackerel protein fractions correlated well with the cell counts of P. marinoglutinosa and A. hyrdrophila. Lobben and Lee (1968) 108/mL, spoilage odors were evident as were increased levels of both TVA and TVBN. The inability of M. colpogenes isolated from radurized mackerel, to bring about spoilage of mackerel homogenate and its protein fractions, despite prolific growth (lo'-lo8 cells/ml) confirmed that Micrococci did not play a significant role in the spoilage of flesh foods.…”