Fernández Gerónimo, Sbres Mauricio, Lado Joanna, Pérez-Faggiani Elena
Unión de Productores y Exportadores de Fruta del Uruguay (UPEFRUY), Rincón 487, Montevideo, Uruguay.
Departamento de Química Orgánica, Laboratorio de Biotecnología de Aromas, Facultad de Química, Universidad de la República, General Flores 2124, Montevideo, Uruguay.
Int J Food Microbiol. 2022 May 2;368:109605. doi: 10.1016/j.ijfoodmicro.2022.109605. Epub 2022 Mar 1.
Citrus sour rot caused by Geotrichum citri-aurantii is one of the most important postharvest diseases in citrus fruit, causing huge economic losses. Traditionally, it has been controlled by the postharvest application of guazatine and propiconazole fungicides, but restrictions in their use make it urgent to find an alternative for sour rot management. Natamycin, a common food preservative, and the organosulfuric compounds extracted from Allium species are safe food additives that control different foodborne pathogens. In the present study, the curative activities of commercial formulations of natamycin (Fruitgard Nat 20) and an Allium extract (PTSO: propyl thiosulfinate oxide; Proallium FRD®), were evaluated for the control of G. citri-aurantii in artificially inoculated lemon fruit. Trials in laboratory and in commercial conditions were carried out to explore the feasibility of including both compounds as part of a safe postharvest sour rot disease control strategy. Under controlled laboratory conditions, sour rot was significatively reduced by 500 mg L of natamycin, 580 mL L of PTSO and 290 mL L of PTSO + 4% of a food coat, applied by immersion. Nevertheless, the maximum dose of PTSO (580 mL L) caused phytotoxicity on the fruit rind. In commercial drenching conditions, 290 mL L of PTSO + 4% of a food coat reduced sour rot incidence similar to conventional treatment. In a packing line treatment, spray application of 500 mg L of natamycin with a previous dip in sodium bicarbonate, resulted in nearly 70% reduction of disease incidence compared to conventional salt application. A second commercial experiment revealed that fruit drenching with 290 mL L of PTSO + 4% food coat followed by an in-line cascade application of 500 mg L of natamycin is completely effective for sour rot control after 20 days at 5 °C. Further exposure at room temperature for 7 d showed a 61% reduction in sour rot incidence compared to the control. Results revealed that natamycin and PTSO are promising tools for sour rot control used alone or combined as part of an integrated postharvest strategy.
由橘青霉引起的柑橘酸腐病是柑橘采后最重要的病害之一，会造成巨大的经济损失。传统上，一直通过采后施用双胍辛胺和丙环唑杀菌剂来控制该病，但对其使用的限制使得迫切需要找到一种替代方法来管理酸腐病。纳他霉素是一种常见的食品防腐剂，从葱属植物中提取的有机硫化合物是控制不同食源性病原体的安全食品添加剂。在本研究中，评估了商业制剂纳他霉素（Fruitgard Nat 20）和一种葱属提取物（PTSO：丙基硫代亚磺酸酯氧化物；Proallium FRD®）对人工接种柠檬果实中橘青霉的防治活性。进行了实验室和商业条件下的试验，以探索将这两种化合物纳入安全采后酸腐病防治策略的可行性。在受控实验室条件下，通过浸泡施用500 mg/L的纳他霉素、580 mL/L的PTSO以及290 mL/L的PTSO + 4%的食品涂层，酸腐病显著减少。然而，PTSO的最大剂量（580 mL/L）对果皮造成了植物毒性。在商业淋洗条件下，290 mL/L的PTSO + 4%的食品涂层降低酸腐病发病率的效果与传统处理相似。在包装线处理中，与传统盐处理相比，先用碳酸氢钠浸泡后再喷施500 mg/L的纳他霉素，病害发病率降低了近70%。第二项商业试验表明，在5°C下20天后，用290 mL/L的PTSO + 4%食品涂层对果实进行淋洗，随后在线串联施用500 mg/L的纳他霉素，对酸腐病的防治完全有效。在室温下再暴露7天，与对照相比，酸腐病发病率降低了61%。结果表明，纳他霉素和PTSO单独使用或作为采后综合策略的一部分联合使用，都是防治酸腐病的有前景的工具。
