A review of Kudoa-induced myoliquefaction of marine fish species in South Africa and other countries

Abstract

Myoliquefaction of fish musculature results in customer quality complaints and in huge economic losses, especially with regard to Pacific hake (Merluccius productus), farm-reared Atlantic salmon (Salmo salar), South African pilchards (Sardinops ocellatus) and Cape snoek (Thyrsites atun). Myoliquefaction, or ‘jelly flesh’, is caused by proteolytic enzymes released by the marine myxosporean parasite, Kudoa thyrsites, after the death of the fish. Currently there are no fast methods of detection for this microscopic parasite, and because myoliquefaction is evident only after 38–56 h post-mortem, infected fish inevitably reach the processor and/or consumer. Several methods of detection have been investigated, but most of these methods are time-consuming and/or result in destruction of the fish, and are thus impractical for fishing vessels and fish processors. Limited research is available on possible means of destroying or inhibiting the post-mortem activity of the parasitic proteolytic enzyme. Means such as manipulating post-mortem pH and temperature control have been suggested; leaving opportunities for research into food technology applications such as cold-chain management and ionising radiation.