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Heterofermentative Lactobacilli Causing Ropiness in Basque Country Ciders
M Dueñas1, A Irastorza1, K Fernandez1
1Departamento de Química Aplicada, Facultad de Química, Universidad del País Vasco, 20080 San Sebastian (Gipuzkoa), Spain.
Journal of Food Protection
|May 25, 2019
Summary
Ropy strains of heterolactic Lactobacillus spp. causing cider spoilage were identified. These bacteria produce slime, tolerate high ethanol and low temperatures, but are sensitive to low pH.
Area of Science:
- Food Microbiology
- Industrial Microbiology
Background:
- Spoilage in bottled ciders can be caused by microbial contamination.
- Ropy spoilage is a textural defect affecting product quality.
Purpose of the Study:
- To isolate and characterize ropy strains of heterolactic Lactobacillus spp. from spoiled ciders.
- To understand the growth characteristics of these spoilage bacteria under various conditions.
Main Methods:
- Isolation of Lactobacillus spp. from spoiled ciders.
- Experimental induction of slime production.
- Growth characterization at different pH, sulfur dioxide (SO2), ethanol concentrations, and temperatures.
Main Results:
- Ropy heterolactic Lactobacillus strains were isolated from spoiled Basque ciders.
- Slime production, a polysaccharide, correlated with increased viscosity during exponential growth.
- Strains exhibited tolerance to 15% ethanol, low temperatures (10-15°C), and up to 50 mg/l total SO2.
- Growth was significantly inhibited below pH 3.7.
Conclusions:
- Heterolactic Lactobacillus spp. are capable of causing ropy spoilage in ciders.
- Understanding their tolerance ranges is crucial for developing control strategies.
- pH is a critical factor limiting the growth of these spoilage organisms.
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