Evolution de la flore fongique de l'oignon (Allium cepa L.) ionisé au cours de l'entreposage / Evolution of fungal flora of irradiated dry onions (Allium cepa L.) during storage

The evolution of fungal flora of irradiated dry onion bulbs stored at room temperature or 4°C was studied during 27 weeks. Three irradiation doses (0.10, 0.15 and 0.31 KGy) were applied. The average storage moisture was 75% at room temperature and 85% at 4°C. The reduction of initial fungal flora was proportional to dose level. After 27 weeks of storage, 0,31 KGy ionized batch stored at room temperature and control showed identical levels of contamination. The combination chilling-ionization gave the best results for the dose of 0.31 KGy. The development of rotting reached a worrying level at room temperature since the 15th week (average of 10%), while at 4°C this level of rotting was observed after 21 weeks of storage. Only ionizing treatment with 0.31 KGy have delayed the progression of rotting particulary when it is associated with chilling. Lastly, no correlation was established between the development of fungal flora and progression of rotting. The fungal flora is not apparently a determinating factor in the progression of rotting.