Spoilage of fresh and lightly preserved fish products is caused by microbial action. This paper reviews the current knowledge in terms of the microbiology of fish and fish products with particular emphasis
on identification of specific spoilage bacteria and the qualitative and quantitative biochemical indicators of spoilage. Sizewnnella putrefaciens and Pseu&monas spp. are the specific spoilage
bacteria of iced fresh fish regardless of the origin of the fish. Modified atmosphere stored marine fish
from temperate waters are spoiled by the CO, resistant Photobacterium phosphoreum whereas
Gram-positive bacteria are likely spoilers of CO, packed fish from fresh or tropical waters. Fish products with high salt contents may spoil due to growth of halophilic bacteria (salted fish) or growth of anaerobic bacteria and yeasts (barrel salted fish). Whilst the spoilage of fresh and highly salted
fish is well understood, much less is known about spoilage of lightly preserved fish products. It is
concluded that the spoilage is probably caused by lactic acid bacteria, certain psychrotrophic Enterobacteriaceae and / or Photobacterium phosphoreum. However, more work is needed in
this area.