Abstract: In this experiment, the plate count method was used to detect the inhibit effects of around 10 biological preservatives, such as gluconolactone, fumaric acid, glycine and others against the microorganisms of the fresh water fish. The results showed that each half inhibit concentration(IC50) is respectively:gluconolactone IC50 0.205%, lysozyme IC50 0.151%, protanmine IC50 0.305%, fumaric acid IC50 0.431%, sodium fumaric acid IC50 0.872%, the glycine IC50 0.172%, potassium sorbic IC50 0.497%, sorbic acid IC50 0.145%, nisin IC50 0.219%. For the sake of considering the cost with the inhibit effects, gluconolactone, glycine and fumaric acid are chosen as anti-microbial agents in processing fresh water fish.

Key words: fresh water fish, anti-microorganism, half inhibit concentration(IC50)