On the use of hot water treatment to control crown rot postharvest diseases of export banana fruit (Musa sp., Group AAA, subgroup Cavendish, ‘Williams’)

International markets set stricter regulations of pesticide residues to reduce the chemical load and to make produce safer for human consumption. Hot water treatment (HWT) is one of the viable physical treatments evaluated to replace fungicides used for quality preservation of bananas. Most studies with HWT were performed with bananas grown in small-scale farms, and with minor cultivars. Our study revisited HWT using bananas grown under commercial orchards for the mainstream market. A set of two experiments were carried out, for the first one, HWT of 45°C; for 10, 15, and 20 min, 50°C for 5, 10, 15, and 20 min, and 55°C for 1, 2, 3, 4 and 5 min were applied by dipping the fruit in a 600-L heated tank. In the second experiment, freshly harvested fruit was cut in clusters, cleaned, and disinfected in a commercial packing house, then inoculated with the causal agents of crown rot and mold (Fusarium semitectum (1×10⁴) + Fusarium proliferatum (1×10⁴) + Colletotrichum musae (1×10³)) and exposed to 55°C for 1, 2, and 3 min, 50°C for 1, 3 and 5 min. In both experiments fruit was subjected to transport simulation of 21 days at 14°C and 85-90% RH, and then commercially ripened and exposed to shelf-life conditions (20°C and 80% RH). Quality and pathological variables were evaluated. The results showed that HWT of 55°C for 1, 2 and 3 min and 50°C for 1, 3 and 5 min were effective in suppressing pathogens growth, both at crown and peel. However, some re-infection with Fusarium spp. may occur after HWT during transit to markets since these fungi are dispersed by air and grow in many surfaces.