A combination of heat treatment and Pichia guilliermondii prevents cherry tomato spoilage by fungi

This study investigated the effectiveness of heat treatment and Pichia guilliermondii, either alone or in combination, to combat postharvest fungal spoilage in cherry tomato fruit. In vitro experiments demonstrated that heat treatment at 38 degrees C significantly inhibited mycelial growth of three different pathogens (Botrytis cinerea, Alternaria alternata and Rhizopus stolonifer Ehrenb). In vivo experiments unveiled that either heat treatment or P. guilliermondii reduced decay caused by these pathogens. Furthermore, a combination of heat treatment followed by the application of P. guilliermondii (H + P) provided the best efficacy in prevention of cherry tomato from fungal spoilage. Following, H + P treatment, electronic nose detected a reduction of volatility in cherry tomato fruit odor, an indicator of preserving fruit's freshness. Scanning electron microscopy unveiled that heat treatment at 38 degrees C for 24 h inhibited hyphae growth and spore germination of R. stolonifer Ehrenb while P. guilliermondii multiplied rapidly on fruit wounds, and its cells had a strong capability of adhesion to the hyphae of R. stolonifer Ehrenb. However, heat treatment also seriously injured P. guilliermondii, therefore P. guilliermondii should be applied after heat treatment. A combination of heat treatment and P. guilliermondii is one of the most effective techniques at controlling postharvest fungal spoilage in cherry tomato fruit. (C) 2009 Elsevier B.V. All rights reserved.