New scientific knowledge in kiwifruit storage using sanitization systems (Ionny^®) avoiding postharvest chemical treatments

Loss of produce during commercial kiwifruit storage is so high as to require the adoption of specific techniques and preventive measures. Postharvest curing techniques alone are not sufficient to guarantee valid economic results, particularly when fruits are harvested in high-humidity environmental conditions due to rain or heavy dew. The incidence of rot due to Botrytis spp. penetrating the pulp at the detachment point of the stalk can reach high percentages (10-20% of damaged fruit), and specific postharvest chemical treatment known as drenching is required. As verified in the past, an alternative to the use of chemicals, with air sanitation of the storage environment using an ionizer (Ionny^®), is possible. Tests carried out during the 2016-17 season have confirmed the validity of this technique in CA storage conditions (-0.5/-0.7°C, RH>90%, CO₂ 3-4%, O₂ 2.5-3%, C₂H₄<0.02 ppm) alongside curing, with results comparable to those obtained using the chemical treatment fenhexamid in a drencher. A batch of ‘Hayward’ kiwifruit produced in the Trentino (Italy) area was divided into three groups: 1) treatment with fenhexamid + curing + CA; 2) curing + CA in an ionized environment; and 3) no treatment + curing + CA (TEST). The trial found over 15% of fruits infected with Botrytis spp. in group 3, and 100% healthy fruits in groups 1 and 2. These results, as well as confirming the outcome of previous trials, have also highlighted that group 2 (CA storage with air sanitized by Ionny^®) produced the best results (firmness, total acidity) both at the end of storage and also after 8 d shelf-life at room temperature.