Effects of the supply chain routes, pre-storage treatments and storage conditions on the microbial quality of 'Nemo-Netta' tomatoes

The effect of disinfecting tomatoes with different solutions (anolyte water, chlorinated water and hot water) or coating tomatoes (with Gum Arabic), on the microbiological quality of tomatoes during storage after transportation in non-refrigerated trucks along three different supply chain routes was evaluated. Pink-matured tomatoes were treated, stored at either ambient (25°C) or cold (11°C), and sampled on days 0, 16 and 30 for quality assessment. An experiment was laid out as a factorial design, split-plot, with supply routes as main plots, storage conditions as subplots and a random allocation of disinfection treatments within subplots. There was a highly significant difference (P<0.001) in the total aerobic bacteria load (log CFU cm^‑2) and marketability (%) of tomatoes in different supply routes, storage environments, and different treatment with disinfectants. Anolyte water was the most effective treatment, which reduced the initial microbial load significantly (P<0.001) from 4.828 to 3.779 and 2.835 log CFU cm^‑2, under ambient temperature and cold storage, respectively. This represented the highest log reduction of 1.049 and 1.993 log CFU cm^‑2, for ambient storage and cold storage, respectively, when compared to untreated samples from Letaba. Furthermore, three-way interaction of supply route, disinfectants, particularly anolyte water, with low-temperature storage remained the most superior treatment in controlling microbial load (by 3.779 log CFU cm^‑2 reduction) and maintaining marketability of pink-matured tomatoes.