This study investigates the effects of post-harvest handling practices prior to storage on the quality of tomatoes in South African supply chains. Pink mature tomatoes were harvested in the morning and afternoon, transported from two farms located 40 km apart to two central pack houses located near each of the farms in Limpopo, South Africa. The samples were transported using bins (468 kg capacity) and lugs (20 kg capacity). After harvesting, the samples were either immediately transported to the pack house and precooled within two hours, or left in the field and transported to the pack house to be pre-cooled after six hours, to simulate delays during transportation. On arrival at the pack houses, the fruit was sampled from the bottom 0.15 m of each lug or bin, precooled using forced air and washed. After precooling, the samples were stored either under ambient conditions or refrigerated storage (15±2 °C). The tomato colour, firmness, weight loss, marketability and pH were monitored over a 24-day storage period. The rate of change of the fruit hue angle was significantly (p ≤ 0.05) higher for samples handled using bins as compared to those handled using lugs. Handling conditions had no significant (p > 0.05) effect on the rate of loss of fruit flesh firmness. The bottom layer of fruit stored in bins showed 30% mechanical damage as compared to 2% in lugs. Harvesting in the morning and pre-cooling within two hours improved fruit marketability and weight-loss by up to 200 kg/ton and 75 kg/ton, respectively, as compared to harvesting in the afternoon and pre-cooling after six hours. As the best practices for industry, the study recommends minimizing the time to pre-cooling, harvesting in the morning and using lugs to handle the fresh tomatoes.

Two infrared systems set at an intensity of 4777 W/m2 with peak emission wavelengths of 2.5 and 3.5 µm were used to produce biltong by drying differently pre-treated meat. In addition to meat texture and colour, the microbial quality of the biltong produced was assessed by quantifying viable heterotrophic microorganisms using a most probable number (MPN) method and by verifying the presence of presumptive Escherichia coli in samples produced using infrared and conventional convective drying. The two infrared drying systems reduced the heterotrophic microbial burden from 5.11 log10 MPN/g to 2.89 log10 MPN/g (2.5 µm) and 3.42 log10 MPN/g (3.5 µm), respectively. The infrared systems achieved an up to one log higher MPN/g reduction than the convective system. In biltong samples produced by short wavelength (2.5 µm) infrared drying, E. coli was not detectable. This study demonstrates that the use of short wavelength infrared drying is a potential alternative to conventional convective drying by improving the microbiological quality of biltong products while at the same time delivering products of satisfactory quality.

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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 o C) 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.

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