Inhibitory effect of sodium metabisulphite and chlorine on growth of Aspergillus spp. and Penicillium spp. strains isolated from marine shrimp

摘要

The sodium metabisulphite (SMB) is used in shrimp farming to prevent melanosis and the 5.0 ppm chlorine (CL) concentration used in the shrimp processing is efficient as a bactericide, but there is no evidence of the effectiveness of these chemical compounds as fungicides. Therefore, the aim of this study was to evaluate the in vitro effect of sodium metabisulphite (SMB) and chlorine (CL) on the growth of Aspergillus and Penicillium species isolated from marine shrimp in different stages of processing. The samples were collected from a frozen shrimp processing industry, located in Piauí State, Brazil. The total fungi and occurrence of Aspergillus and Penicillium species were evaluated. For in vitro sensibility test using the diffusion disk in agar method, five concentrations of SMB (0%, 1%, 3%, 5% and 10%) and six of CL (0, 1, 2, 3, 4 and 5 μg mL-1) were used. The fungal counts in the different processing stages ranged from 1.74 to 3.38 CFU g-1. Twenty-nine Aspergillus strains were isolated, prevailing A. versicolor (59.3%) and twenty-two of Penicillium, prevailing P. citrinum (74%). One strain of A. flavus was AFB1 producer. All the isolated strains of P. citrinum produced citrinin. All tested species were in vitro sensitive to 3% of SMB, except the A. flavus. The 10% concentration of SMB inhibited the in vitro growth of all strains. The CL concentrations tested did not inhibit the studied species growth and SMB concentrations above 3.0% inhibited in vitro the growth of the tested strains.