How to identify moldy corn? Does only moldy corn contain mycotoxins?
Mycotoxins are invisible, intangible, odorless, and tasteless, so many people think that only moldy corn can contain mycotoxins, and there is no mycotoxins in non-moulded corn. This is a misunderstanding.
Many investigation and testing reports on feed raw materials have shown that: corn, wheat bran, soybean meal and other feed materials have a high detection rate of mycotoxins. For example, Zhang Chengren and others found that: The positive detection rates of vomitoxin were: 11.1% , 72.7% , 98.8% .
Identification method of moldy corn
1. The moldy corn shows that the corn husk is particularly easy to separate.
2. Observe the germ. If there is a large black or dark gray area inside the corn germ, it is moldy corn, and if there is a small black spot at the bottom, it is high-quality corn.
3. In terms of taste, good corn gets sweeter the more you eat it, while moldy corn tastes very bitter when chewed in your mouth.
4. In terms of plumpness, moldy corn has a low specific gravity and the grains are not full. Take a handful of grains floating in the water.
5. We should also be wary of unscrupulous traders who use saliva oil to polish moldy corn and dry it, and some unscrupulous elements spray germinated corn with herbicides and dry it for sale.
6. The blackening of corn kernels is caused by long-term high humidity and high temperature.
7. The outer skin of the germ is green, which is caused by early threshing and too late to thresh.
8. There are green or black spots in the germ skin, which means it has been stuffy for a long time.
The main cause of mildew is humidity, which requires us to pay attention to humidity and harvesting weather conditions when storing corn, and use antifungal agents reasonably.
Does only moldy corn contain mycotoxins?
The answer is of course no! Mycotoxins are secondary metabolites secreted by molds, and the amount of mycotoxins is not directly proportional to the amount of mycelium. What can be seen is only the hyphae of the mold, not the mycotoxins. Mycotoxins are invisible to the naked eye and can only be seen with high-end equipment. Sometimes there are many hyphae, and the mycotoxin content may not be high; sometimes the mycelium does not exist, but the toxin concentration may be very high. The reason is that mycotoxins are particularly stable in grains. Even if the mycelium has been decomposed or removed by physical methods, the toxins will still remain in the corn. Moreover, moldy corn has been treated on the surface. Although the mold on the surface has been cleaned, the mycotoxins that penetrate deep into the tissue still exist. It is recommended to use an appropriate amount of mold remover for treatment.