Heterofermentative Lactobacilli Causing Ropiness in Basque Country Ciders.

Ropy strains of heterolactic Lactobacillus spp. were isolated from bottled spoiled ciders produced in the Basque Country. The isolates were able to produce slime experimentally on glucose containing medium and apple must. The production of ropy slime occurred during exponential growth and the increase in viscosity was correlated with production of polysaccharide. They were characterized with regards to growth at different pH, sulfur dioxide (SO2), ethanol and temperatures and showed similar behavior. All ropy strains grew in the presence of high ethanol concentrations (15%) and at low temperatures (10 and 15°C). In addition, these were tolerant to 10, 25 and 50 mg/l of total SO2 (pH 3.8), but with longer lag times as the concentration of SO2, increased. However, the ropy lactobacilli studied were affected by the pH of the medium and in general pH below 3.7 limited their growth seriously.