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The efficacy of ultrasonic fumigation for disinfestation of storage facilities against postharvest pathogens

Daus, Avinoam, Horev, Batia, Dvir, Orit, Ish-Shalom, Shahar, Lichter, Amnon
Postharvest biology and technology 2011 v.62 no.3 pp. 310-313
Alternaria alternata, Botrytis cinerea, Glomerella cingulata, Penicillium expansum, chlorides, conidia, direct contact, disinfestation, food industry, fumigation, pathogens, storage time, vegetables
Inoculum of postharvest pathogens can accumulate inside storage rooms and contaminate new batches of fruit and vegetables, but this chain can be broken by disinfecting storage facilities between storage periods. Quaternary ammonium (QA) has been known for over 50 years as an efficient disinfectant against microorganisms, with wide applications in the food industry. The aim of this study was to determine the efficacy of didecyldimethylammonium chloride (Sporekill, designated here as QAˢᵏ), against development of Botrytis cinerea after direct exposure or by ultrasonic fogging. Following direct exposure to a concentration of QAˢᵏ below 5mgL⁻¹, a population of 10⁴ conidia of B. cinerea was inactivated after 2min; ultrasonic fogging with QAˢᵏ at 500mgL⁻¹ took 30min to achieve consistent inactivation. Fumigation at 20°C was considerably more effective than fumigation at 5°C, and similar results were obtained for three other postharvest pathogens, Penicillium expansum, Colletotrichum gloeosporioides and Alternaria alternata. These results show that conidia of B. cinerea are highly sensitive to direct exposure to QAˢᵏ, but that effective sanitation of a storage facility by ultrasonic fumigation requires a QAˢᵏ concentration two orders of magnitude greater.