Leong S L, Hocking A D, Pitt J I, Kazi B A, Emmett R W, Scott E S
CSIRO Food Science Australia, PO Box 52, North Ryde, NSW 1670, Australia.
Int J Food Microbiol. 2006 Sep 1;111 Suppl 1:S10-7. doi: 10.1016/j.ijfoodmicro.2006.02.005. Epub 2006 May 19.
The presence of the mycotoxin, ochratoxin A (OTA), has been reported in Australian grape products. Comprehensive surveys of Australian wines have determined that the frequency and level of OTA contamination are low. Aspergillus carbonarius is the primary OTA-producing species associated with grapes in Australia, and all isolates tested to date produce OTA. Aspergillus niger is isolated more frequently from vineyards, however, few strains produce OTA. A. carbonarius and A. niger exist as saprophytes in the top layer of soil beneath vines, from where they are thought to be blown onto bunches. The level of A. carbonarius in soil may be reduced by temperatures above or below the optimum temperature for survival (25 degrees C), by high soil moisture content, and by modifications to tillage and mulching practices. A. carbonarius is an opportunistic pathogen of damaged berries. In the absence of damage, spores may exist on berry surfaces without causing visible rots. Aspergillus rots are associated with black Aspergillus species, primarily A. niger, A. carbonarius and A. aculeatus. The potential for such rots is increased with berry damage, inoculum coverage and berry maturity. Susceptibility to berry splitting is related, in part, to bunch structure, and may be variety-dependent or influenced by rainfall, irrigation and canopy management. Black Aspergillus spp. are closely associated with berries near the main stem of the bunch. During winemaking, around 80% of the OTA initially present in grapes is removed, primarily with the skins and pulp during pressing. Additional reductions occur with the removal of precipitated grape and yeast solids. Bentonite in white wine and yeast hulls in red wine were the most effective non-carbonaceous fining agents for the removal of OTA.
据报道，澳大利亚葡萄产品中存在霉菌毒素赭曲霉毒素A（OTA）。对澳大利亚葡萄酒的全面调查表明，OTA污染的频率和水平较低。炭黑曲霉是澳大利亚与葡萄相关的主要OTA产生菌，迄今为止测试的所有分离株都能产生OTA。然而，黑曲霉在葡萄园中的分离频率更高，但很少有菌株能产生OTA。炭黑曲霉和黑曲霉在葡萄藤下土壤表层以腐生菌的形式存在，据认为它们是从那里被风吹到葡萄串上的。土壤中炭黑曲霉的数量可能会因高于或低于其最适生存温度（25摄氏度）的温度、高土壤湿度以及耕作和覆盖方式的改变而减少。炭黑曲霉是受损浆果的机会性病原菌。在没有损伤的情况下，孢子可能存在于浆果表面而不引起可见的腐烂。曲霉腐烂与黑色曲霉种类有关，主要是黑曲霉、炭黑曲霉和棘孢曲霉。随着浆果损伤、接种物覆盖和浆果成熟，这种腐烂的可能性会增加。浆果裂果的易感性部分与果串结构有关，可能因品种而异，或受降雨、灌溉和树冠管理的影响。黑色曲霉属与果串主茎附近的浆果密切相关。在酿酒过程中，葡萄中最初存在的OTA约80%会被去除，主要是在压榨过程中与果皮和果肉一起去除。随着沉淀的葡萄和酵母固体的去除，OTA会进一步减少。白葡萄酒中的膨润土和红葡萄酒中的酵母皮是去除OTA最有效的非碳质澄清剂。
