engleski

ANTIMICROBIAL ACTIVITY OF SELECTED RED AND WHITE WINES AGAINST ESCHERICHIA COLI IN MARINATED FISH FILLETS

Five different wines (standard Graševina, macerated Graševina with and without sulphites, rosé and standard Plavac Mali), all typical Croatian wines, were tested to determine the antimicrobial activity against Escherichia coli (ATCC® 25922) using sea bass (Dicentrarchuslabrax) fillets as food matrix. Fish fillets were marinated for two hours in a 1:1 wine:water mixture. Sterile water was used for the control. The filets were minced and the E. coli inoculum (7 log CFU/25g) was added before the samples were vacuum packed and refrigerated. Enumeration of the bacteria was done on days three and seven, after 24 hrs incubation on Tryptone Bile X-GLUC (TBX) agar. The minimal inhibitory concentration (MIC) and total phenolic (TP) content of the wine samples were determined. The highest number of E. coli was detected in the control sample (6.81 and 7.22 log CFU/25g), while the lowest counts of 4.95 and 6.04 log CFU/25g were detected in fillets marinated in macerated Graševina (MIC 1284mg GAE/L, TP = 2699 mg GAE/L) after three and seven days, respectively. Addition of sulphites in macerated white wine did not enhance antimicrobial effect. Samples marinated in rose showed bacterial growth from 5.46 to 6.73 log CFU/25g. Standard Graševina and standard Plavac Mali had a similar effect on the E. coli after three days (5.32 and 5.42 log CFU/25g), with Plavac Mali showing reduced growth after seven days. The most prominent inhibitory effect was detected for macerated Graševina and standard Plavac mali, as these wines resulted in the lowest MIC and TP values.

wines ; E. coli ; antimicrobial activity ; fish

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