Division of Food Biotechnology, Food Research Institute, NARO, 2-1-12 Kannon-dai, Tsukuba, Ibaraki 305-8642, Japan.
Food and Agricultural Materials Inspection Center (FAMIC), 2-1 Shin-toshin, Chuo, Saitama, Saitama 330-9731, Japan.
Toxins (Basel). 2019 Mar 2;11(3):140. doi: 10.3390/toxins11030140.
Aflatoxins (AF), produced by several species, are visible under ultraviolet light if present in high amounts. AF detection can be improved by adding activated carbon, which enhances the observation efficiency of weakly AF-producing fungi. However, commercial activated carbon products differ in their characteristics, making it necessary to investigate which characteristics affect method reproducibility. Herein, the addition of 10 activated carbon products resulted in different AF production rates in each case. The differences in the production of aflatoxin G₁ (AFG₁) were roughly correlated to the observation efficiency in the plate culture. Trace element analysis showed that the concentrations of several metal ions differed by factors of >100, and the carbons that most effectively increased AFG₁ production contained higher amounts of metal ions. Adding 5 mg L Fe or Mg ions increased AFG₁ production even without activated carbon. Furthermore, co-addition of both ions increased AFG₁ production stably with the addition of carbon. When varying the concentration of additives, only AFG₁ production increased in a concentration-dependent manner, while the production of all the other AFs decreased or remained unchanged. These findings suggest that a key factor influencing AF production is the concentration of several metal ions in activated carbon and that increasing AFG₁ production improves AF detectability.
黄曲霉毒素（AF）是由几种真菌产生的，如果其含量高，在紫外线照射下可见。通过添加活性炭可以提高 AF 的检测能力，因为活性炭可以提高对弱产 AF 真菌的观察效率。然而，商业活性炭产品在特性上存在差异，因此有必要研究哪些特性会影响方法的重现性。在此，在每种情况下，添加 10 种活性炭产品会导致不同的 AF 产生率。AFG1（黄曲霉毒素 G1）产生率的差异与平板培养中的观察效率大致相关。微量元素分析表明，几种金属离子的浓度相差 100 多倍，而最有效地增加 AFG1 产生的碳则含有更多的金属离子。即使没有活性炭，添加 5mg/L 的 Fe 或 Mg 离子也能增加 AFG1 的产生。此外，两种离子的共同添加能稳定地增加 AFG1 的产生，同时伴随着碳的添加。当改变添加剂的浓度时，只有 AFG1 的产生呈浓度依赖性增加，而所有其他 AF 的产生则减少或保持不变。这些发现表明，影响 AF 产生的关键因素是活性炭中几种金属离子的浓度，而增加 AFG1 的产生可提高 AF 的检测灵敏度。
