CHANGES IN MICROBIAL-POPULATION DURING FERMENTATION OF TROPICAL FRESH-WATER FISH VISCERA

Freshwater fish viscera (FV) was homogenized, mixed with 10% (W/W Of F V) molasses and 0, 2 or 4% salt and allowed to ferment at ambient temp erature (26 +/- 2 degrees C) under microaerophilic conditions. The res ults revealed a reduction in total viable count and the number of spor es, coliforms, Escherichia coli, staphylococci and enterococci and an increase in yeasts and moulds and lactic acid bacteria during fermenta tion. Coliforms and E. coli were found to be absent after 6 d and ente rococci on 8th day. The presence of salt resulted in a marginally lowe r number of all organisms except yeasts, moulds and lactic acid bacter ia. Inclusion of either 0.5% propionic acid, 0.3% calcium propionate o r 0.1% sorbic acid suppressed growth of yeasts and moulds with propion ic acid being the most effective. The study indicated that a microbiol ogically stable product could be prepared by ensiling fish viscera wit h 10% molasses and 0.5% propionic acid.