THE EFFICACY OF POSTHARVEST BIOCONTROL TREATMENTS IN CONTROLLING SPOILAGE OF TOMATO FRUIT IN SOUTH AFRICAN COMMERCIAL SUPPLY CHAINS

Abstract

In this study, the effectiveness of postharvest biocontrol treatments using B-13 yeast isolate in controlling spoilage of tomato fruit was evaluated in selected commercial supply chains in South Africa. Mature green tomatoes were harvested from three commercial farms in Limpopo (Musina, Mooketsi and Pont drift) during summer and transported through the three supply routes to Pietermaritzburg, where four postharvest treatments were applied to the fruit, then stored in ambient and cold storage (11^oC) conditions. The fruit was sampled over a 30-day storage period and its firmness, colour, weight loss, marketability and incidences of decay assessed. Fruit stored under ambient conditions had higher incidences decay, diseases and physiological disorders compared to samples stored in cold storage, with these incidences varying widely with pre-storage treatments applied on the fruit. The supply chain route significantly (p≤0.05) influenced the physicochemical and subjective quality of tomato fruit. Biocontrol treatment reduced mass loss of fruit and had comparable physicochemical and subjective attributes to chlorine treated fruit. Biocontrol treatment was also effective in maintaining fruit firmness and colour for the first eight days of storage. Biocontrol treated fruit had 7.9% and 7.7% lower mass loss compared to control and chlorine fruit treated fruit, respectively.  Although, biocontrol treatment showed promising prospects in controlling tomato spoilage and improving its shelf life, integrating it with other treatments should be further tested to improve its efficacy.