Características físico-químicas e microbiológicas da silagem ácida de pescado

Abstract

This research aimed to evaluate the physical-chemical and microbiological characteristics of acid silage of whole fish submitted to two processes of acidification in different periods of storage. The first silage was produced with acetic acid (5% of the biomass) (S1) and the second addition of lactic acid (5% of the biomass) (S2). The materials were stored in an environmental chamber at 37 ° C for 28 days. The analyses were performed for the raw material and the periods of one, seven, 14, 21 and 28 days storage. The pH, the melting and production of oil were evaluated for each period. Microscopic analysis was performed after two Gram staining of silage, and the cultivation, quantification and isolation of Enterobacteriacea, Staphylococcus spp., Lactobacillus spp., Filamentous fungi and yeasts. With 28 days of acidification were carried out chemical analyzes of both silages, as well as the raw material. The average pH of the silage with lactic acid was significantly lower than that observed for the silage made with acetic acid. In one week, the silage was melted and oil production. Enterobacteriaceae were only detected for samples of the raw material. There was development of filamentous fungi and yeasts up to seven days for both silages. Regression analysis estimated that the optimal time for stabilization of silage lactic acid is 7.6 days, proving to be efficient for the reduction of Staphylococcus spp. population. Both silages had high protein content, and may be a good alternative for feeding non-ruminants. This work represents the first study in Brazil that evaluates the production of fish silage increased by lactic acid and the results indicate better pH drop and faster reduction of Staphylococcus spp., when compared to fish silage increased by acetic acid.