ABSTRACT

Koji mold, which belongs to the Aspergillus section Nigri, is used in the production of shochu. The section Nigri is composed of very morphologically similar members that in some cases produce mycotoxins, which rises concerns as to whether the presence of mycotoxin-producing fungi in shochu producing sites can compromise consumer safety. Thus, we examined the presence of mycotoxin-producing sec. Nigri fungi in six shochu factories (named A–F) in Japan. Airborne fungal levels in the factories were determined, and a traditional koji called “kona-koji” made from the mold naturally present in factory C (Aogashima village) was analyzed. Isolates of sec. Nigri fungi were identified morphologically and confirmed via cytochrome b gene analysis. In factory A (Nago city), airborne fungal levels of sec. Nigri were 4,000 and 100 cfu/m³ in the koji-making and fermentation rooms, respectively. In factories B, C, and D, the levels were 40, >10⁴ cfu/m³, and 100 cfu/m³, respectively. In factory F (Iki city), there were high levels of airborne white-koji mold (a white mutant of Asp. luchuensis). The most dominant fungal species of sec. Nigri was isolated and identified as Asp. luchuensis via genetic analysis. This is likely to have originated from the commercial fermentation culture used. Asp. niger and Asp. luchuensis were isolated from kona-koji. Mycotoxin production (ochratoxin and fumonisin B2) by Asp. luchuensis (eight strains) and Asp. niger (three strains) was virtually inexistent; only one strain of Asp. niger was positive for fumonisin B₂. This study clearly shows that mycotoxin-producing fungi are not dominant in the fungal flora present in the shochu factories examined and therefore, that the liquor can be safely fermented.

Implications: In this study, we examined the presence of mycotoxin-producing Aspergillus sec. Nigri fungi in six shochu (Japanese distilled beverage) factories. The most dominant fungal species of sec. Nigri was isolated and identified as Aspergillus luchuensis (black-koji mold). The proportion of mycotoxin-producing Aspergillus niger and Aspergillus carbonarius was very small. In addition, the Asp. niger isolated from koji mold did not have the ability to produce ochratoxins or fumonisin B. This study clearly shows that shochu can be safely fermented.

摘要

曲霉属于黑曲霉科，用于生产烧酒。Nigri部分由形态非常相似的成员组成，在某些情况下会产生霉菌毒素，这引发了人们对在烧酒生产地点存在产生霉菌毒素的真菌是否会危及消费者安全的担忧。因此，我们检查了产生霉菌毒素的 sec 的存在。日本六家烧酒工厂（名为 A-F）的黑真菌。测定了工厂中空气中的真菌水平，并分析了一种名为“ kona-koji ”的传统酒曲，该酒曲由 C 工厂（Aogashima 村）中天然存在的霉菌制成。秒的分离物。尼格里真菌通过形态学鉴定并通过细胞色素b基因分析确认。在 A 工厂（名护市），空气中的真菌水平为 sec。在制曲室和发酵室中， Nigri分别为 4,000 和 100 cfu/m ³。在工厂 B、C 和 D 中，水平分别为 40、>10 ⁴ cfu/m ³和 100 cfu/m ³。在 F 工厂（壹岐市），空气中的白曲霉菌（一种白曲霉的白色突变体）含量很高。sec的最主要的真菌种类。Nigri被分离并鉴定为Asp。通过遗传分析的绿楚。这很可能源于所使用的商业发酵培养物。ASP。尼日尔和Asp。luchuensis是从kona-koji中分离出来的。Asp.生产霉菌毒素（赭曲霉毒素和伏马菌素 B2） 。luchuensis（八株）和Asp。尼日尔（三个菌株）几乎不存在；只有一种天冬氨酸。尼日尔的伏马菌素 B ₂呈阳性。该研究清楚地表明，在所检查的烧酒工厂中存在的真菌菌群中，产生霉菌毒素的真菌并不占优势，因此可以安全地发酵酒。

启示：在这项研究中，我们检查了产生霉菌毒素的曲霉菌sec 的存在。六家烧酒（日本蒸馏饮料）工厂的黑菌。sec的最主要的真菌种类。Nigri被分离并鉴定为Aspergillus luchuensis（黑曲霉菌）。产霉菌毒素的黑曲霉和炭黑曲霉的比例很小。此外，Asp。从曲霉菌中分离出的尼日尔没有产生赭曲霉毒素或伏马菌素 B 的能力。这项研究清楚地表明，烧酒可以安全发酵。