Heat Resistance of Talaromyces flavus and Neosartorya fischeri Isolated from Commercial Fruit Juices

Abstract

The heat resistance of two molds believed to have survived the thermal process applied to two commercial “shelf stable” fruit juices was studied. Neosartorya fischeri had a D-value of 1.4 min at 190°F (87.8°C) and a z-value of 10°F (5.6°C). Talaromyces flavus had a D-value of 2.2 min at 195°F (90.6°C) and a z-value of 9.5°F (5.2°C). Under certain conditions, both molds possess sufficient heat resistance to survive commercial thermal processes if ascospores are present in sufficient numbers.