Pg. 36-39 Evaluation of a ‘one sheet fits all carton types’ SO² sheet on HLH Mauritius and McLean’s Red litchi fruit

A trial was conducted to evaluate a newly developed ‘one sheet fits all carton types’ SO₂ sheet. The sheet was used in combination with export and local market cartons from three manufactures. The trial was performed with both the HLH Mauritius and McLean’s Red cultivars and the fruit were stored under export simulation conditions (30 days at 1 ° C) followed by a shelf life phase of 12 days at 13° C. The sheet was found to reduce fungal infections and significant differences were recorded between the sheet and no-sheet treatments during the mid to late stages of the shelf life period. An interaction between the sheets and the cartons were also recorded. Generally, export cartons gave better results than less ventilated local market cartons.

Summary:

• The study evaluated a newly designed one-sheet fits all SO₂ sheet for controlling fungal infections in litchi fruit during storage and simulated export conditions.
• The sheet was tested in combination with three carton types: two export cartons and one less ventilated local market carton.
• Two litchi cultivars were used: HLH Mauritius and McLeans Red.
• Fruit was stored for 30 days at 1°C followed by shelf life at 13°C for up to 12 days.
• The new SO₂ sheet significantly reduced fungal infections compared to no sheet and the old sheet, especially in the mid to late shelf life stages.
• Export cartons generally showed better fungal control than the less ventilated local market carton.
• The design of the new sheet with small perforations allows it to fit all carton types and maintain airflow through ventilation slits.
• McLeans Red fruit was more susceptible to fungal infections than HLH Mauritius.
• SO₂ residue analyses showed the sheets did not result in residues exceeding the 10 ppm safety limit.
• The study recommends use of the new sheet in well-ventilated export cartons for best fungal control in the South African litchi industry.
• The trial design was statistically sound using randomized blocks and analysis of variance for treatment comparisons.