Antimicrobial effects of grated radish and radish sprout extract against microorganisms derived from lightly pickled vegetables and various food-spoilage yeasts

The antimicrobial activities of grated radish and radish sprout extracts against food-spoilage yeasts and bacteria were evaluated. The viable bacterial counts in lightly pickled cucumbers were between 4.0 log and 4.8 log CFU/g, whereas viable yeast counts increased from ≤1 log to 4.5 log CFU/g after incubation for 21 d at 10 °C. The bacterial counts decreased from 5.2 log to 2.8 log CFU/g, whereas yeast counts were <1 log CFU/g in cucumbers lightly pickled with 9 % (w/w) grated radish for 21 d. Both grated radish and sprout water extracts showed stronger antimicrobial activity against yeast than against bacteria in broth. The antimicrobial activity against 16 species of food-spoilage yeasts differed, even among species of the same genus. Our results suggest that radish can prevent yeast-induced deterioration in lightly pickled vegetables.