Fate of Escherichia coli and E. coli O157:H7 in apple juice treated with propolis extract

Abstract

Fruit juices are targets of spoilage moulds, yeasts and acid tolerant bacteria. They might be contaminated with bacte from raw materials, environment, packaging and during the handling of the product. These contaminations have frequently result in the spoilage of fruit juice and consequently commercial losses. The objective of this study was to determine the influence of prop lis in apple juice against Escherichia coli and E coli O157:H7 strains of the spoilage and pathogenic bacteria. For this purpose, api juice was obtained from fresh apples and then was pasteurised. The pH value, titrable acidity (as % malic acid) and Brix degree this apple juice were 3.72 ± 0.10, 0.67 ± 0.05% and 12.1 ± 0.01, respectively. Propolis extract at 1, 2 and 5% concentrations we tested to determine of E coli and E coli 0157:H7 inhibition using paper disc diffusion method. The control treatment had no propolis extract. The apple juices were contaminated with these bacteria, and the activity of propolis was observed at first, 18th, 24 th, 4: and 72nd hours at 4 and 25°C. The number of cells in the tubes was counted using serial dilution method. Results indicated that propolis extract at 2 and 5% concentrations had significant antimicrobial activity against E coli and E coli O157:H7, therefore we can cc elude that propolis extract is worthy of further study as a natural preservative for the foods prone to microbial spoilage.