Identification, characterisation and inhibition of Geotrichum pseudocandidum spoilage microbe in Gastrodia elata tuber

Abstract

Gastrodia elata tuber is vulnerable to spoilage after harvested. A fungal strain Geotrichum pseudocandidum causing the spoilage was isolated from Gastrodia elata tuber and identified in this study. The log phase of the strain growth during incubation at 28 °C was from 24 to 48 h. The pH for highest spore production and largest colony formation were 5–6 and 7–9, respectively, while the temperature for them was 20–30 °C. Antifungal natamycin and tea polyphenols extract inhibited the stain at minimum inhibitory concentration of 0.25 and 0.5 mg mL−1, respectively. A short‐time heating treatment at temperature at 65 °C for 10 min also effectively prevented the strain growth. As tea extract is a GRAS (generally recognised as safe) food ingredient, the tea extract treatment could be a safe and non‐thermal treatment to prevent the spoilage of Gastrodia elata tuber with less loss of heat‐sensitive bioactives and other nutrients.