Optimization of the Biological Preservative formula for Penaeus vannamei By Response Surface Methodology

Penaeus vannamei is the most widely aquacultured shrimp in the world. However, it is vulnerable to bacteria spoilage. Recently, the use of biological preservatives to defend against bacteria has attracted much attention. However, the practical effects of these preservatives remain unclear. In this work, response surface methodology with the Box-Behnken experimental design was adopted to investigate the effects of three biological preservativesnisin, tea polyphenol (TP), and epsilon-polylysine (epsilon-PL)on the bacterial growth in P. vannamei. The optimal preservative formula was obtained, which was nisin at 0.04 g/100 mL, epsilon-PL at 0.48 g/100 mL, and TP at 1.06 g/100 mL. Under the optimal conditions, shrimp had a total bacteria number as low as 1.81 x 10(3) CFU/g, which was not significantly different from the practical determinations. The findings indicated that this model was effective to analyze the antimicrobial effects of preservatives and to optimize the combination of biological preservatives.